We (students, professor, and TA)
are going to work together to determine the topics we will study for
the latter part of the class. Now that each of you have submitted
an article that you feel would be worthwhile to study, we are all going
to work together to decide which articles we will cover. Please
email me your top 5 choices, numbered from 1 (favorite) to 5 (fifth
favorite), and a short, less than 100 words description of why you
chose each of these five article. Your rationale for choosing the
articles should include why you think it is important for us to study
these topics, and/or why you think the topics are interesting.
The articles are listed below.
The format of the assignment
should be as follows:
Your name
Bio 325
1) Favorite: Article title
This is my favorite article because...
2) Second Favorite:
Article title
This is my second favorite
article because...
3) Third Favorite: Article
title
This is my third favorite
article because...
4) Fourth Favorite:
Article title
This is my fourth favorite
article because...
5) Fifth Favorite: Article
title
This is my fifth favorite
article because...
Please include your assignment in the body of an
email and send it to
me by 11am on October 10, 2006. This homework will be graded on
a
scale of 0-3 points based on your rationale for choosing the
five articles. I will subtract 0.5 points for each day
late. After I receive all of your
submissions, I will post the schedule for the rest of the semester.
Articles: in no particular order:
Article Title: The Genetic Architecture of Sucrose Responsiveness in
the Honeybee (
Apis mellifera L.)
Authors: Olav Rueppell, Sathees B. C. Chandra, Tanya Pankiw, M. Kim
Fondrk, Martin Beye, Greg Hunt, and Robert E. Page
Journal Title: Genetics
Volume: 172, Issue 1, January 2006
Page Numbers: 243-251
Date of Publication: January 2006
Discussion
The
chief question posed in this study regards the way in which genetic
architecture affects behavioral syndromes through the study of the
pollen-hoarding syndrome of the honeybee Apis mellifera L. Being a
psychology major myself, I feel that social behavior is influenced by
two kinds of factors - environmental factors, and biological factors.
Through a perspective involving genetics, this article clarifies the
importance of the understanding of behavioral syndromes through the
understanding of genetic architecture, and combining the realms of
biology and psychology, emphasizes how this knowledge mixes to give us
a clearer understanding of "social evolution". By gaining better
insight into the biological and genomic system of the pollen-hoarding
synrdome of the honeybee, we may be enlightened in our future endeavors
towards understanding not only psychological and neurological pathways,
but also studies of "naturally occurring behavioral syndromes". The
study of the honeybee's pollen-hoarding syndrome is considered to be a
"hard-wired" trait, and to the authors knowledge, is "the first study
of genetic architecture of a behavioral reflex". Personally I feel that
this article not only gives us more insight into the fields of biology
(genetics), I believe that it also stimulates interest into the unknown
and dark realm of behavioral psychology, (
i.e. how we behave, and why we may be predisposed to behave in (a)
certain manner(s)).
Title: Live Bacterial Vaccines- a review and identification of
potential hazards
Author’s Names: Ann Detmer and Jacob Glenting
Journal Title: Microbial Cell Factories
Volume 5, Article 23
Date Published: June 23, 2006
Questions Posed:
• What are the advantages of using live bacterial vaccines/
disadvantages?
• What could be the effects caused by the release of the recombinant
DNA into
nature?
• What should you consider during the development of these vaccines?
• What methods are already available, how are scientists going to go
about
finding new methods?
What makes this article interesting?
This article gives the history of the use of bacterial vaccines, which
dated
back to the late 1800’s, but was not a useful tool until the 1980s. The
first
uses of this method failed due to the sequence reverting back to the
harmful
strain. This article also explains what can make a safe vehicle for the
delivery of a vaccine; it also lets the readers know the aspects other
than
science that need to be considered, such as cost efficiency and patient
comfort. The article also describes how these pathogens can be made
safe for
intake; they mutate the genes that encode for enzymes or delete harmful
factors, some strains are even created so that they may not be
replicated
inside the human body.
The article describes how they test the DNA of the patients to see if
the
vaccine has entered the chromosome of the human. In this case they use
PCR
(polymerase chain reaction) to sequence the DNA. They can then also
test how
this insertion affects the rest of the gene activity of the organism.
This article explains how the use of the study of Genetics can lead to
preventing diseases and immune deficiencies. It also explains why
methods of
sequencing are so important in the world today, not just to figure out
the
genome of an organism, but to also learn how genes can be affected by
the
environment as well as attempts to remove disease will affect the genes
and the
way information is coded.
ARTICLE TITLE: Highly efficient EIAV-mediated in utero gene transfer
and expression in the major muscle groups affected by Duchenne muscular
dystrophy
AUTHORS' NAMES: Gregory LG, Waddington SN, Holder MV, Mitrophanous KA,
Buckley
SMK, Mosley KL, Bigger BW, Ellard FM, Walmsley LE, Lawrence L, Al-Allaf
F,
Kingsman S, Coutelle C, Themis M
SOURCE: Gene Therapy, Volume 11, Issue 14, Pages 1117-1125, July 2004
Duchenne muscular dystrophy (DMD) is an X-linked genetic disorder
characterized by degeneration of the skeletal muscles. Post-natal gene
therapy
for this disease has currently proved unsuccessful due to immune
response
against the treatment and the inability to provide widespread gene
transfer.
The authors of this article attempt to determine whether such obstacles
can be
overcome by administering gene therapy prenatally as a cure or
treatment method
for DMD.
In an attempt to answer this question, researchers designed an
experiment
in which mouse fetuses were injected with a virus that would provide
gene
transfer to the various muscle groups affected by DMD. The fetuses were
then
analyzed based on the number of injections they had received and the
site of
the injections. Results indicated that, even after a single injection,
there
was widespread gene expression in the various muscles of the fetuses,
including
the heart, diaphragm, liver, and limbs. In addition, many of the
complications
associated with post-natal gene therapy, particularly rejection of the
treatment by the immune system and the inability to reach several muscle
groups, were absent in this pre-natal approach.
In recent years, Duchenne muscular dystrophy has received worldwide
attention, especially through the annual Jerry Lewis fundraising
telethon.
Most DMD patients live only to be 20 or 30 years old, and there is
presently no
cure for this fatal disease. While gene therapy is a relatively new
field in
modern medicine, it is being sought as a potential treatment for
currently
incurable diseases. The authors of this article present us with
supporting
evidence that pre-natal gene therapy may one day provide a method of
preventing
or treating DMD. If so, this would certainly be a significant
breakthrough in
the scientific community.
How
does the mode of inheritance of a genetic condition influence families?
A
study of guilt, blame, stigma, and understanding of inheritance and
reproductive risks in families with X-linked and autosomal recessive
diseases,
James, Cynthia A. ScM, PhD1; Hadley, Donald W. MS2; Holtzman, Neil A.
MD, MPH3;
Winkelstein, Jerry A. MD3, The American College of Medical Genetics
Volume
8(4), pp 234-242, April 2006.
They basically surveyed families with genetic disorders and asked them
questions
about their knowledge of inheritance and reproductive risk; their
concern for
future family-members; their feelings of guilt and blame and
stigmatization.
I think it is interesting because it focuses on the people that have
genetic
disorders and how they feel about possibly passing these genetics
disorders on
to their family.
"Reversal
of Type 1 Diabetes by Engineering a Glucose Sensor in Skeletal
Muscle." Alex Mas, Joel Montane, Xavier M. Anguela, Sergio Munoz, Anne
M.
Douar, Efren Rui, Pedro Otaegui, Fatima Bosch. Vol. 55, issue 6.
p1546-1553.
This article focuses on the use of gene therapy, a relatively new and
innovative
domain in science aimed to manipulate genes to solve health problems.
Researchers used gene therapy, specifically the AAV1 vector, to solve
implications with diabetes type one. The greatest problem in diabetes
type 1
patients is the inability of the body to maintain normoglycemia due to a
defective pancreas. Traditional treatments focus on performing the
pancreas’s
duty, by manually injecting needed insulin only in response to blood
sugar
fluctuations. A secondary complication occurs when the basal rate, in
between
meals, of blood sugar levels cannot be achieved. Researchers wanted to
find out
if insulin uptake areas, like skeletal muscles, would be a better area
to
manipulate to not only basal rate normoglycemia and prevent secondary
complications. They tested mice by injecting them with AAV1 gene
vectors to
pair with glucokinase to regulate insulin uptake from the blood stream
to
skeletal muscle. Essentially, researchers found that the vector paired
with
the glucose enzyme could in fact turn on and off insulin uptake and
ultimately
achieve normoglycemia. Their results posed the question of whether this
procedure in mice could be replicated in humans and achieve the same
results.
Experimenters would like to use larger mammals to test applicability in
humans
and any safety concerns. The alternative perspective to treat the
uptake area
instead of focusing on the outtake area is a major advance in treatment
of all
health issues. Success from this experiment will hopefully encourage
other
researchers to use gene therapy along with a holistic treatment plan
approach
to solve issues in new and creative ways. Diseases and defects affect
vast
ranges of functions due to the complexity and systematic nature of the
human
body. Could gene therapy thus be used to enhance the works of one area
of a
system to combat the problems from another area of that system? If the
answer
is yes, as this experiment has supported, then many unanswered
questions in
medicine may could start to be answered.
Müller,
U. F. "Re-creating an RNA world." Cellular & Molecular Life
Sciences 63.11 (2006): 1278-1293. Academic Search Premier. 9 September
2006.
Description of the Article
The article talks about the RNA World Hypothesis. The RNA world
hypothesis proposes that RNA was the first life-form on earth, later
developing a cell membrane around it and becoming the first prokaryotic
cell. The RNA World hypothesis is supported by the RNA's ability to
store, transmit, and duplicate genetic information, just like DNA does.
RNA can also act as a ribozyme (an enzyme made of ribonucleic acid).
Because it can reproduce on its own, performing the tasks of both DNA
and proteins (enzymes), RNA is believed to have once been capable of
independent life. But the RNA World Hypothesis has not been fully
proved true yet. After giving a short background on prebiotic chemistry
and in vitro evolution, the discussion focuses on the generation of
three important components of an RNA world: a sufficient polymerase
ribozyme, self-replicating membrane compartments and ribozymes that are
capable of performing basic metabolic processes. The article proposes
that synthesis of self replicating system from the catalytic RNA would
be a milestone in the search for the origins of life and for our
understanding of life itself. Some steps like modification of several
existing ribozymes along with the development of new ribozymes have
been taken and very soon there would a development of a self
replication system from RNA. This would prove that RNA world hypothesis
is true.
Reason to study the article in clas
This article could be used for class study and discussion due to
several reasons. Firstly, the topic is related to our curriculum and we
have briefly talked about this in the class. Secondly, the article
provides some updates on what research work is going on and what
progress has been made to prove that RNA world hypothesis is true. If
we can prove that life originated from RNA then the whole perspective
of functions and structures of proteins, DNA and RNA will be changed.
Also, many myths and misunderstandings regarding the origin of life can
be disregarded if this study is successfully conducted. Origin of life
is one the most interesting and important part of biology and there it
should be studied in detail in the class.
Genome-wide linkage analysis of heroin dependence in Han Chinese:
Results from wave one of a multi-stage study.
Stephen J. Glatt, Jessica A. Su, Shao C. Zhu, Ruimin Zhang, Bo Zhang,
Jixiang Li, Xiaobo Yuan, Jianhua Li, Michael J. Lyons, Stephen V.
Faraone, Ming T. Tsuang. American Journal of Medical Genetics Part B:
Neuropsychiatric Genetics. Volume 141B, Issue 6, p 648-652 (5 September
2006). Published Online: 19 Jul 2006.
Heroin addiction is a worldwide epidemic with its use on the rise.
Genetic
contribution seems to be higher for heroin addiction than any other
illicit
drug; previous studies suggest that genes account for between 23 and
54% of
total liability of heroin dependence. Even though gene association
studies
have been performed, the specific genes that govern this heroin
dependence
remain unknown. This article describes a study where researchers try to
find
out which, if any, specific genes control heroin dependence; this is the
question being asked.
Researchers used people from the Yunnan Province in China as their study
subjects. People with siblings or other family members were asked to
participate in this experiment and the family member was also evaluated
for
possible inclusion in the study. Blood from the subjects was drawn, and
DNA
was extracted from cell lines and genotyped. Computer programs were
used to
collect data on genetic markers and there were two areas of interest
that
seemed to link to heroin addiction.
I chose this article because it seemed very relevant to our study of
genetics in
several ways. The purpose of learning about genetics is to be able to
use what
we know and apply it to some good use. This article shows just that:
researchers trying to identify genes responsible for a dangerous drug
addiction. This also ties into our discussion of nature vs. nurture.
These
researchers say that dependence is largely based on genetic
characteristics.
However, while they have positive proof in that they found two loci
having
suggestive evidence for linkage, they don’t do much to disprove the
environmental influence since the source of these subjects came from an
area
that produces more than 20% of the world’s heroin. They do show
weaknesses in
their study as well as their plans for further studies in linking the
loci to
heroin dependence. Overall, they carried out the rules of strong
inference:
they devised a hypothesis, designed an experiment, carried out the
experiment,
and they will repeat the experiments with refined approach based on
their
results.
Article Title: Anthrax lethal factor and edema factor act on conserved
targets
in Drosophila.
Authors: Annabel Guichard, Jin Mo Park, Beatriz Cruz-Moreno, Michael
Karin, and
Ethan Bier
Journal Title: Proceedings of the National Academy of Sciences of the
United
States of America
Date: February 23, 2006
Volume: 103
Issue: 9
Pages 3244-3249
(DOI: 10.1073, PNAS: 0510748103)
Summary: The article talks about an experiment that these authors did
to see if
the toxin, Anthrax, has similar effects in a Drosophila (fruit fly) as
in
humans. If the experiment proves to be successful, researches will be
able to
use fruit flies in experiments to better understand the effect of
toxins in
humans. Anthrax secretes three exotoxins, a lethal factor, edema
factor, and a
protective antigen. Each of these exotoxins may cleave or inhibit
different
genes in the development of the fruit fly. The results show that
anthrax poses
similar development effects in fruit flies as in humans.
Reason: It is important for us to look at an article like this, because
humans
can be exposed to different toxins at any moment, and we should
understand how
these toxins work in our body. We need to understand how they inhibit
or their
activities in gene expression in the human body or any other animal.
Excess of counterclockwise scalp hair-whorl rotation
in homosexual men
By Amar J. S. Klar, Journal of Genetics, Vol. 83, No.
3, pages 251-255, December 2004
The article I chose deals with the question of a
person's sexual preference. Is it innate, learned or
due to a combination of both? This article looks at
the direction of scalp hair-whorl rotation
development from a common genetic mechanism and
whether or not this same mechanism specifying mental
makeup influences sexual preference. I think this
article would be interesting to discuss in class
because this is a highly debated topic, is sexual
orientation nature or nurture. We touched a little in
class already but this article exams another
similarity between homosexual men that isn't commonly
found in heterosexual men.
The
role of microRNA genes in papillary thyroid carcinoma, Huiling He,
Krystian
Jazdzewski, Wei Li, Sandya Liyanarachchi, Rebecca Nagy, Stefano
Volinia, George
A. Calin, Chang-gong Liu, Kaarle Franssila, Saul Suster, Richard T.
Kloos, Carlo
M. Croce, and Albert de la Chapelle, Proceedings of the National
Academy of
Sciences of the United States of America, vol. 102, 19075-19080,
December 27,
2005
The questions posed in the article are “What is the role of microRNA in
papillary thyroid carcinoma (PTC)?” and “What causes predisposition for
PTC?”
MicroRNAs, previously thought of as “junk” DNA in the genome, were only
recently recognized as a class of gene products. Scientists know that
some
people inherit predispositions for PTC and their attempts at finding
specific
gene mutations for this predisposition have been unsuccessful
(eliminating one
of the hypothesis explaining what causes predisposition of PTC).
Because of
these unsuccessful previous attempts, these researchers hypothesized
that
microRNA were involved with the predisposition for PTC and that they
worked as
regulatory genes instead of protein-producing genes. The research
suggests that
the predisposition to PTC is caused by a subtle interaction among many
genes
instead of just one. After comparing samples from malignant tumors and
healthy
cells adjacent to the tumors, researchers concluded that several miRNA
types
were overregulated while transcript and protein from other genes were
down-expressed. Specifically, the scientists found that when three
dramatically
overexpressed miRNA types were found in the presence of two other miRNA
types,
the cell would become cancerous. This article would make for an
interesting
class because it would show a genetic cause behind the correlation
between
family cancer history and a person’s chance of getting cancer.
Blood group A and B antigen expression in human kidneys correlated to
A(1)/A(2)/B, Lewis, and secretor status, Breimer ME, Molne J, Norden G,
Rydberg
L, Thiel G, Svalander CT, TRANSPLANTATION, volume: 82 issue: 4 pg:479
-485, AUG
27, 2006
This article attempts to solve the problem of ABO blood type barriers.
Transplantation of organs cannot be made among people with different
blood
types. In this study, the three types of blood are studied, revealing
three
different groups of blood, with major, minor and minimal antigen
expression
patterns. It categorizes the donors into A1, A2, B, with Lewis and
secretor
status, corresponding them into three different intensities designated
as 3+,
1+, and +. Drug treatments were used to test the organ biopsies as
well, and
the results indicate an insufficiency to use pretransplant antibody
removal and
standard immunosuppressive drugs as the only pretreatment to
transplantation.
ABO blood incompatibility occurs despite splenectomy, and whether to use
anti-CD20 antibodies instead of Splenectomy will increase the long-term
graft
survival in renal transplantation remains to be further studied.
This is an interesting article in the sense that blood transfusion
barriers have
always been present and accepted. Scientist now are reviving an
interest in the
differences in these blood types, and trying to find a way to cross the
ABO
barriers in organ transplantation.
Pollard, K. S., Salama, S. R., Lambert,
N., Lambot, M., Coppens, S., Pedersen, J. S., Katzman, S., King, B.,
Onodera, C., Siepel, A., Kern, A. D.,
Dehay, C., Igel, H., Ares, M.,
Vanderhaeghen, P. and Haussler, D. 2006. An RNA gene expressed during
cortical development evolved rapidly in humans. Nature, 443: 167-72.
Pollard
et al. studied the genomic regions in humans and identified the regions
that have a significantly accelerated rate of substitution compared to
that of the chimpanzee. They found that one of the most dramatically
accelerated regions is an RNA gene (HAR1F), which is expressed in
Cajal-Retzius neurons in the human neocortex early in human embryonic
development. HAR1F was detected along with reelin protein which showed
that both HAR1F and reelin are expressed in the same cells. One
question remaining is about the role of HAR1F and HAR1R in cortical
development and whether or not HAR1F directly or indirectly influences
the expression of reelin or its receptors. These human accelerated
regions (e.g. HAR1F) are one of the focuses in the attempt to decode
the key events of human evolution.
“Generations
of Cloned Transgenic pigs in omega-3 fatty acids.” Jing Kang.
Nature Biotechnology. Volume 24 (435-436). Published April 2006.
This article would make an interesting topic because it is a very
controversial
one. For one, the transgenic pigs were cloned via nuclear transfer.
Cloning
is a major thing many people despise mainly for religious and ethical
reasons.
However, as a class, we should put our scientific coats and think
thoroughly
whether current meat should be replaced with “hfat-1 transgenic pig.”
The
latter meats may reduce the prevalence of heart disease, cancer,
diabetes,
arthritis, and depression.
Genetic engineering is advancing, and so are the food prices. Should
the vast
population be fed with minute amounts of organic goods that require a
lot of
labor, or should genetic engineering contribute largely to the quality
and
quantity of food?
Organic food is expensive. Generation of fat-1 transgenic livestock may
be an
economical and sustainable choice. Studying these types of articles
will lead
give us a better understanding of transgenes, its benefits and its
defects.
A
Study of Identical Twins' Palmprints for Personal Verification; Adams
Wai-Kin
Konga, David Zhanga, and Guangming Luc; Pattern Recognition; volume 39;
issue
11; pages 2149-2156; November 2006. (available online June 16, 2006)
This experiment attempts to discover if identical twins' palmprints can
be used
for identification purposes. In other words, it answers the question:
are
identical twins' palmprints identical or different? The device used to
examine
the palms was referred to as an "automatic palmprint identification
algorithm,"
and it was able to distinguish the different line patterns on identical
twins'
hands. The results of the experiment show that the three main lines and
other
larger lines on two identical twins' hands are genetically the same.
However,
smaller lines differ between twins, showing that nature and nurture
both play
roles in determining the lines on a person's hand. Therefore,
palmprints are
unique to each individual and can be used to identify people, even
identical
twins. I think this article would be interesting to study because it
goes along
with what we have been learning in class about nature and nurture. It
also
supports the idea that they work together, instead of one being
completely
dominant over the other.
"Paternally
inherited HLA alleles are associated with women's choice of male
odor", Suma Jacob, Martha McClintock, Bethanne Zelano, & Carole
Ober, Nature
Genetics, Volume 30 No 2, pp 175-179, published January 22, 2002
This article describes the ability for women to detect difference of
one human
leukocyte antigen (HLA), or human MHC, among male odors even though
background
odors which are influenced by cultural practices and the rest of the
genome my
mask the olfactory cues. The ability for women to discriminate and
choose odors
is based on the HLA alleles she has inherited from her father and not
her
mother. The data shows that the paternally inherited HLA-associated
odors
influence odor preference, or in other words, who she may or may not be
attracted to. There is not one male odor that is preferred among
everyone, most
women prefer different odors. This article is interesting because it
plays on
the saying that women are attracted to men with qualities similar to
their
fathers. In retrospect this is true because the alleles for this
ability are
inherited by their father but actually the tests show that women are
attracted
to men with HLA alleles most unlike their own. So, in my opinion, it is
saying
that women are attracted to men that are the opposite of their fathers.
This
article sparked an interest in me because it showed, for the most part
why
women are attracted to certain types of men. I think other females and
maybe
some males in this class would be interested about it as well. Maybe
one day we
will be able to skip dating and go straight to their DNA to see if they
would
suit us or not.
Title: Tetracycline-Regulated Gene Expression in Replication-
Incompetent Herpes Simplex Virus Vectors
Authors: FALKO SCHMEISSER, MEGAN DONOHUE, and JERRY P. WEIR
Journal Title: HUMAN GENE THERAPY
Volume and Page numbers: 13:2113–2124
Date of publication: December 10, 2002
This
article adresses Herpes Simplex Virus vectors ability in gene delivery,
and regulating the gene expression in these vectors. This vector is
used frequently in the gene delivery to the neuron and the nervous
system. Herpes simplex virus normally infects human neurons and
naturally establishes a latent state in which the viral genome persists
in a nonintegrated form, without apparent disruption of neuronal
function. These characteristics, and the ability of the vector to be
engineered to accommodate large inserts of foreign DNA, make HSV an
especially attractive vector for studying the central nervous system
and the neuron, as well as a potential gene therapy vector. The main
purpose of this study is to make modifications to expand the range and
sensitivity of inducible gene expression in the HSV vector system, so
that it can be used to turn gene expression on and off in the
ireplication-incompetent herpes simplex virus vectors to be used in
neuron like cells.
Rapid Communication: Serotonin Transporter Promoter Polymorphism and
Differences
in Alcohol Consumption Behavior in a College Student Population,
Depetrillo,
Paolo B., Vasilopoulos, Nicholas L, Philbeck, John W., Herman, Aryeh I.,
Alcohol and Alcoholism, 38, 446-449, 2003.
Introduction:
Alcohol misuse is generally associated with the depiction of the
college life. An individual’s first drink away from home usually occurs
in
their college years, in a social setting, at a party, or at a club.
Those
first few drinks may not seem like such a big deal until they unravel
into the
fatal potential of binge drinking. The purpose of this study is to
explore
what leads college students to binge drinking or drinking to get drunk,
and if
they are caused by genetic factors that support this type of behavior.
Alcohol misuse is an increasing problem among college campuses today
when
students are found unconscious on the couch from alcohol poisoning,
individuals
are being killed on the street by drunk drivers, and people’s children
are found
left to die after a Frat Pledge Party. Researchers have found that
there are
differences in the serotonergic functions deliberated by the serotonin
transporter protein promoter polymorphism (5-HTTLPR) among college
students,
which may give rise to explaining why some students have a greater
tendency to
drink than others do. The most common type of insertion deletion
polymorphisms
lies in the promoter area in the human 5-HTT gene, and lays the
foundation to a
long allele (L) as well as a short allele (S). The higher the frequency
of
this S allele may suggest a higher ethanol tolerance and alcohol self
–regulation for adults that are 26 years old or younger. Individuals
who were
homozygous with the S allele in a group of adult alcoholics had a higher
frequency of binge drinking than those who were did not carry the S
allele, or
S homozygous.
Method:
262 college-aged participants of Caucasian, Asian, African-American,
and other
ethnic descents answered a survey questionnaire using an ordinal scale.
The
participants were also genotyped for the 5-HTTLPR gene for further
genetic
examination. The survey asked questions such as “On how many occasions
have
you had a drink of alcohol in the past 30 days?” or “Think back over
the last 2
weeks. How many times have you had five (for male students) four (for
female
students) or more drinks in a row?”, and a drink of alcohol was
operationally
defined as a 12-ounce serving in a can or a bottle, or a 4-ounce wine
glass.
The survey also answered questions such as whether the student was a
binge
drinker, who drinks dangerously excessive amounts of alcohol in one
sitting, or
a student who drinks purposefully just to get drunk.
Results:
The Caucasian population of the participants, 204 out of the 262
participants, were the only group further analyzed in the results to
avoid
ethnic comparison. This is not a study of which ethnic group can get
more
smashed on a Saturday night, it is a study of the gene that some people
possess
and how it is significant in their behavior around alcohol.
Discussion:
Researchers did match their predictions as the results do suggest a
major association with the 5-HTTLPR gene with an increase in alcoholic
behavior
and consumption in Caucasian participants. Those students who were
homozygous
for the S allele of the 5-HTTLPR had the highest frequency of drinking
more
often to get drunk, as well as binge drinking. Those students who were
heterozygous for the S allele, or were homozygous with the L (long)
allele had
a lower tendency to drink excessively. This study poses the finding that
individuals with the homozygous S allele may use alcohol to reduce
stress, as
these individuals showed greater levels of anxiety. Nonetheless, this
study
does reveal that 5-HTTLPR does have an impact on drinking behavior, and
also
increases our knowledge about the genetic risk that we should be aware
of to
protect ourselves and our loved ones.
The Cells and Logic for Mammalian Sour Taste Detection, A. L. Huang, X.
Chen, M.
A. Hoon, J. Chandrashekar, W. Guo, D. Trankner, N. J. P. Ryba & C.
S. Zuker,
Nature, Volume 442, pp 934-938, 24 August 2006.
Have you ever thought about what happens when you put something in your
mouth and taste it? What exactly does it mean to taste something sweet
or sour?
And why have we evolutionarily developed these tastes? This article not
only
explains the mechanism that lets us taste “sour,” but also uses the
findings
from that experiment to research the pH sensitivity of cerebrospinal
fluid.
We all have five basic tastes: sweet, sour, salty, bitter, and umami
(the
flavor of MSG). I never really understood or even questioned what
tasting a
certain flavor meant. Was the same “thing” that told my brain I was
tasting
sweet, the same “thing” telling my brain I was tasting sour? Apparently
not.
The scientists working on this project determined that PKD2L1 (a
polycystic-kidney-disease-like ion channel), what they proposed as the
candidate for the mammalian sour taste detector, was expressed in taste
receptor cells (TRCs) distinct from the TRCs responsible for the other
tastes.
Basically, this ion channel that correlated with “sourness” was
activated in
certain taste cells independently from the other tastes that could be
expressed.
Furthermore, when mice were genetically engineered to have these certain
populations of TRCs removed, (the ones that expressed PKD2L1), the mice
were
completely devoid of taste responses to sour stimuli! This shows that
without
these PKD2L1 expressing cells, the mice could not taste (respond) to
sour
stimuli. But the capacity to respond to the other tastes (sweet,
bitter…) was
unaffected. Not only did this show that PKD2L1 expressing cells were
the only
ones responsible for tasting sour, but it also showed that the 5
different
tastes were distinct and independent from each other. The article
provides
helpful figures and diagrams to help understand this.
From previous work in isolating the receptors for sweet, bitter, and
umami, the
scientists were able to show that each of the 5 tastes were mediated
by, “highly
selective receptor proteins expressed in distinct and independent
populations of
TRCs.” From this conclusion, they came up with the hypothesis that sour
taste
should also be mediated by these highly selective, distinct, and
independent
TRCs.
Since I didn’t know much about how something that goes into our mouth
and onto
our tongue actually gets registered in our brain as either sweet or
bitter or
sour, I thought it was interesting to find out what exactly is
happening on our
tongue. In mammals, TRCs have specialized microvilli that project out
into the
taste pores. It’s in these pores that the interaction between
“tastants” and
our taste receptor proteins occur. These TRC compartments are actually
the
only place taste receptor proteins function! From this information, the
scientists hypothesized (correctly so) that since the receptor proteins
were
located here, the receptors themselves should also be located in these
taste
pores.
Since PKD2L1 was found to be involved in detecting and responding to pH
levels,
another interesting question evolved from these conclusions: Was PKD2L1
expressed in cells elsewhere in the body for this same function? Other
than in
the taste receptor cells of the tongue to detect sourness (implying
higher
acidity and lower pH levels), PKD2L1 was also found in neurons
surrounding the
central canal of the spinal cord! (Another helpful figure is provided
to show
the localization of PKD2L1 expressing cells around this region.)
Because PKD2L1 was known for detecting pH changes, these scientists
came up
with another hypothesis predicting that, “these cells might be part of
the
homeostatic circuitry responsible for monitoring and reporting the pH
of the
CSF…that these neurons should trigger action potentials in response to
acid
stimulation.” Their hypothesis was correct, for they found that when
they
genetically engineered mice to have fluorescently labeled PKD2L1 in CSF
cells,
and then varied the pH levels, there was a marked increase in the action
potential frequency of these labeled cells (but not in the cells without
PKD2L1). A few charts and visual representations are also provided here
to
explain the action potential firing in response to pH stimulation.
So, after learning that PKD2L1 functions as a sort of indicator of pH
levels,
it was interesting to see how the ion-channel can be found in two
completely
different parts of the body for similar reasons. In the tongue, PKD2L1
is
necessary to detect sour tastes, thereby preventing mammals from eating
highly
acidic foods that may be rotten or spoiled. While in the fluid of the
spinal
cord, it’s used as a sensor to indicate the pH variations of the CSF,
(since
any slight deviations from a pH of 7.4 within the body could be
detrimental.)
As the article more eloquently states, “… [it’s] a surprising unity in
the
cellular basis of pH sensing in very different physiological systems.”
Effect of Long-Term Somatotropin Treatment on Body Composition and Life
Span in
Aging Obese Zucker Rats, Michael J. Azain, J. Roger Broderson, and Roy
J.
Martin, Experimental Biology and Medicine 231 (1): 76-83, 2006
This research tested the effect of the growth hormone STH
(Stomototropin) on fat
composition in rats. It also tested the life span of rats compared to
the
percentage of fat in their bodies. The growth hormone STH stimulates
more
uptake of food but increases the amount of lean tissue and decreases
fat. In
humans it has been found that there is a direct effect of increase body
fast on
dying. The more fat content one has the more likely he/she is to die at
an
earlier age. A decrease in hormone is proved to lead to an increase in
body fat
content. It has been found that STH works as an anti-aging substance.
The more
growth hormone one has the longer he/she will live.
For the first experiment, the researchers tried to determine if STH had
an
effect on growth and body fat content. They had both male and female
lean and
obese rats. Some were given STH and others were not. The beginning body
weights
of the lean rats were about the same. The obese rats all had about the
same
weight as well. They determined the fat composition and weighed certain
organs
to see the effect of STH. For the second experiment, they tested to see
if a
decrease in body fat did cause the rat to live longer. This was again
done on
male, female, lean and obese rats.
The overall significance of this article is to show that fat percentage
in the
body does have a substantial effect on life span. The more fat
percentage you
have the shorter your life span. It also shows that one hormone, STH,
cannot
fix the problem of obesity. Many different factors including exercise
and a
balance diet are essential to having low fat percentage. People are
always
trying to find an easy way out of their problems such as one pill to
make them
be skinny. This shows that just an increase of STH does not have the
best
effect. Although it may lower fat composition, the obese mice lived an
even
shorter life. It is important to find a balance. The STH affected the
renal
organ in mice. Increased hormones in humans may have the same negative
effect
on other organs. I found this to be very interesting. Currently with
the diet
craze and professional athletes using growth hormone, I think it is
interesting
to learn how steroids do affect the body and fat composition.
Title: “Extreme skewing of X chromosome inactivation in mothers of
homosexual
men”
Authors: Sven Bocklandt, Steve Horvath, Eric Vilain, and Dean H. Hamer
Journal: Human Genetics
Volume: 118 Pg. 691-694 Feb. 2006
The issue of nature versus nurture has been an ongoing debate for many
years.
Topics such as a child’s language development are generally considered
by many
to be influenced by both nature and nurture; however, a person’s sexual
orientation is almost never regarded as one of these topics. Most would
state
that a person’s sexual orientation is strictly due to environmental
factors.
Recent researches, however, have indicated that a person’s sexual
orientation
might be influence by genetic. To test whether sexual orientation is
related to
genetic, researchers gathered a sample of mothers of heterosexual men
and a
sample of mothers of homosexual men. Researchers tested the genetic
information
of both samples of mothers and found that mothers of homosexual men have
statistically more extreme skewing of X chromosome inactivation than
mothers of
heterosexual men.
In a female, each cell has two X chromosomes, but one X chromosome is
randomly
inactivated into a barr body. Because the process is random, the
distribution
of cells in the female body having one particular inactive X chromosome
should
be close to 50 percent. Extreme skewing of X chromosome inactivation is
the
phenomenon in which one particular X chromosome is found to be
inactivated in a
very large percentage of the cells in the body. Researchers believe
that extreme
skewing of X chromosome inactivation is due to the cells having some
sort of
bias for one X chromosome over the other; however, researchers have
very little
information on the cause of this bias. After the researchers gathered
and
analyzed the data, the results showed that there is a significant
increase in
extreme skewing of X chromosome inactivation in mothers with homosexual
sons
compared to mothers with heterosexual sons. The result becomes even more
significant in mothers of two or more homosexual sons. Though this
research
does not relate to mothers of homosexual females nor does it prove that
sexual
orientation is caused by genetic, it does provide some evidence
relating sexual
orientation and genetic.
This article would be very interesting to discuss in class because it
provides a
different perspective on homosexuality. If sexual orientation is
influenced by
genetic, then homosexuality can be considered a genetic disorder like
Down
Syndrome. As researches continue to provide more information, the debate
regarding the relationship between sexual orientation and genetic will
continue
to increase; therefore, our class should take this opportunity to
discuss this
topic and debate whether homosexuality should be considered a disease
if it is
found to be influenced by genetic.
Title:
Potent inhibition of HIV-1 gene expression and TAT-mediated apoptosis
in human T cells by novel mono- and multitarget anti-TAT/Rev/Env
ribozymes and a general purpose RNA-cleaving DNA-enzyme
Author: Hoshang Unwalla, Samitabh Chakraborti, Vikas Sood, Nidhi Gupta
and Akhil C. Banerjea
Journal: Antiviral Research
Volume 72, Issue 2 , November 2006, Pages 134-144
Questions: How
and by what mechanisms is it possible to reduce the HIV-1 TAT
protein
created in HIV infected cells and what real effects would it have when
in the real human body (not in vitro)? Could this, at some point,
become a plausible treatment for HIV?
I
think that this is a great article review because it shows great
genetic insight to the functioning of one of the deadliest viruses in
the world right now. It also offers an experimental treatment to the
HIV virus which may be complicated yet covers many of the core topics
of genetics.
Minoo Rassoulzadegan, et al., "RNA-mediated non-mendelian inheritance
of an epigenetic change in the mouse." Nature, Volume 441,
p469-474, 25 May 2006. 17 August 2006
DNA has long been thought as the sole carrier of information from one
generation to the next. However, a study by
a team led by Minoo Rassoulzadegan at Sophia Antipolis University in
Nice, France, conclude that RNA as well as DNA
can
carry information from parent to child. This is a clear
contradiction
to Mendel's law of inheritance stating that the combination
of
dominant and recessive genes dictate the offspring's
characteristics. The dominant mutant gene Kittm1Alf results
in a
spotted tail
and the normal Kitgene codes for a brown tail. A mouse
with two normal copies of the gene, and a mouse with one Kittm1Alf gene
were then bred. However, mice that inherited two normal
copies of the gene also had spotted tails.
When the team examined sperms from males
carrying one normal and one mutant copy of the Kitgene,
they found that
the sperms contained RNA,
as well as DNA. The researchers then injected this RNA into
fertilized eggs of normal mice,
which do not carry the Kittm1Alf gene, and found that the treated eggs
developed into mice with spotted tails.
Controlled expression of cardiac-directed adenylylcyclase type VI
provides
increased contractile function; Gao MH, Bayat H, Roth DM, Yao Zhou J,
Drumm J,
Burhan J, Hammond HK; Cardiovascular Research; Volume 56(2); 197-204;
November
2002.
Description: This article falls under the field of cardiology research,
specifically heart failure, which is the number one cause of death in
the
United States. It deals with the controlled expression of
adenylylcyclase type
VI (AC6) in the heart, which provides increased contractility in
response to
heart failure. AC6 is an enzyme in the beta-adrenergic receptor
signaling
pathway which catalyzes the formation of cAMP from ATP. Increased cAMP
production is known to increase heart contractility.
Controlled expression refers to the ability to activate or deactivate a
gene.
The main question posed by this paper is whether or not AC6 can or can
not be
regulated in cardic-specific expression while still increasing heart
function.
This article proposes the use of tetracycline as the regulator for
cardiac-specific expression of AC6. Regulation is of central importance
to
these studies because in the case that AC6 expression leads to negative
outcomes in a patient, one would need the ability to deactivate the
gene.
This paper would be a useful and interesting learning tool for the
class,
because it addresses the practical application of genetics for medical
research. More specifically, it discusses gene transfer techniques, the
use of
transgenic mice as model systems, regulated gene expression, and the
use of
polymerase chain reaction (PCR). All of these topics are important to
the field
of genetics and are applicable to our class, and this article is a good
display
of how several genetic techniques can be combined to address medical
ailments.
Molecular origins of rapid and continuous morphological evolution,
Fondon, John W. III, and Garner, Harold R., PNAS, vol. 101,
18058-18063, December 28, 2004
"Genetics, development and evolution of adaptive pigmentation in
vertebrates", H E Hoekstra, Heredity (2006), Vol. 97, 222–234,
Published online 5 July 2006
This article addresses the following questions: 1) Are adaptive changes
predominantly caused by mutations in regulatory
regions or coding regions? 2) is adaptation driven by the fixation of
dominant mutations? and 3) to what extent are parallel phenotypic
changes caused by similar genetic changes?
I
feel as though this would make for an interesting class because
pigmentation is such a visual topic. Plus the main issues don't seem to
be too far beyond the scope of the class, i.e. not too overly complex
issues. In addition, it allows up to study both the genotype and the
phenotype with relative ease due to the extreme visual nature of
pigmentation.
“The Contributions of Sex, Genotype and Age to Transcriptional Variance
in
Drosophila Melanogaster”, Gibson, Greg, Wei Jin, Gisele
Passador-Gurgel,Rebecca
M. Riley, Russell D. Wolfinger, Kevin P. White, Nature Genetics, 29,
389-395,
2001
In this research article, researchers examine the magnitude of gene
effects of
various components. Contributions of sex, genotype and age to
transcriptional
variance in Drosophila melanogaster are researched carefully in this
experiment. The question of whether sex, genotype, or age affect
transcription
and therefore the pheneotype is being raised in this article. And if
any of
these various components do, by what quantity, or to what degree are
effects
observed. This interpretation is compromised to some extent by issues
relating
to power and experimental design.
This article explores the many other possible factors thay may
contribute to
gene expression. The study introduces to us how your phenotype maybe
affected
by numerous and various factors. Furthermore, this article shows
importance of
experimental design. How we must be careful to what type of experiment
we set
up, so we can get the best fit data for results.
Molecular Genetics of Parkinson’s Disease, M.I. Shadrina and P.A.
Slominsky,
RUSSIAN JOURNAL OF GENETICS, Vol. 42, No.8, pp. 858-871, August 2006
The article reviews the significant advances that have been made in
studying
genetic factors underlying Parkinson’s disease. It fist talks about the
monogenic (familial) form of the disease and describes the novel genes
that
have been discovered, whose mutations and polymorphisms lead to the
parkinsonism development (particularly the parkin and dardarin genes).
The
article then talks about the more frequent, sporadic form of the
disease and
describes the potential candidate genes for this sporadic form that
have been
discovered. The article then mentions that the number of studies that
have been
carried out for most of the candidate genes is too small to conclusively
evaluate the individual contributions of the genes to the parkinsonism
development. The question that the article poses is: what is the
genetic basis
of the more frequent, sporadic form of Parkinson’s disease? (is the
sporadic
form of the disease caused by mutations and polymorphisms of the same
genes as
the monogenic form of the disease or is it caused by mutations and
polymorphisms of the candidate genes or a combination of the two?). The
article
proposes a way to answer this question (by conducting a thorough
analysis of
the genes related to the monogenic form of Parkinson’s disease in
patients with
sporadic and familial parkinsonism and by carrying out associative
studies of
the candidate genes of the sporadic disease form). The article
concludes by
pointing out that if this question is answered, it will become much
easier for
other questions to be answered. These questions include: what are
genetic
markers of the high risk for Parkinson’s disease?, what is the
molecular basis
of the pathogenesis of Parkinson’s disease?, and what are possible
methods of
preclinical diagnostics and pathogenic therapy on this basis?
I chose this article because I think that it would make for a very
interesting class. This is because Parkinson’s disease is an important
problem
in the society in which we live. In most world populations, at least
2-4% of
persons older than 65 and at least 1% of persons older than 50 years of
age
suffer from Parkinson’s disease. This may not seem like a lot, but it
actually
is when you consider that there are over 6 billion people on Earth. And
in
recent years, the amount of people with Parkinson’s disease has
increased and
the age of onset of Parkinson’s disease has decreased. So Parkinson’s
disease
is definitely a huge problem around the world. I think that it would be
beneficial for students to understand the genetics behind this disease
and what
causes this disease. I believe it is much more interesting to learn
about things
that actually affect people around the world (such as the genetics
behind
diseases) than things that have no effect on people. And I believe that
the
genetics behind Parkinson’s disease is particularly interesting and
certainly
worth learning about. Therefore, I think that the article that I chose
would
make for a very interesting class.
Worsening of obsessive–compulsive symptoms under methadone
tapering
Yasser Khazaal, a, Sonia Krenza, Messaoud Benmebareka and
Daniele Fabio Zullinoa
Progress in Neuro-Psychopharmacology and Biological
Psychiatry, Volume 30, Issue 7, 30 September 2006, Pages
1350-1352
The article is interesting because OCD is a disorder that
many people are familiar with and it is common belief that
people have a genetic disposition for rituals or control
issues. However, now with the idea that opioids can lead
to OCD tendencies in seemingly "normal" people can help
explain other disorders brought about due to drug intake.
This article contains no figures so it will not be visually
compelling, but it does have a case study and I think could
lead to broader discussions of drug use and the
temporary/permanent neural alterations that can occur as a
result.
The Use of Racial, Ethnic, and Ancestral Categories in Human Genetics
Research,
Race, The Race, Ethnicity, and Genetics Working Group, American Journal
of
Human Genetics, Volume 77, pgs. 519-532, August 29, 2005
Within this article titled “The Use of Racial, Ethnic, and Ancestral
Categories in Human Genetics Research,” many questions arise about the
use of
racial, ethnic, and ancestral categories in genetics research and how
do we
categorize people based on genetic factors. The main question that is
put
forward in this article is the question of whether the use of racial,
ethnic
and ancestral categories even belongs in human genetic research. Many
believe
that the use of these categories can justify and even perpetuate racial
and
ethnic discrimination. Some who favor the use of these categories
believe that
using race, ethnic, and ancestral history can actually dispel
stereotypes by
showing how biologically close we are to one another. . The evidence
that
there are health disparities within each categorical group suggests
that there
is a need for these categories, but many would prefer to be liberated
from
these categories because of the stereotypes and the discrimination
received
from these categories.
Another question that is raised within this research article is how one
distinguishes racial, ethnic, or ancestral groups from the other. The
problem
with finding the answer to this question is that it is very hard to
categorize
groups because of the diverse backgrounds of individuals and the complex
outlines that are needed to differentiate the human population. Also,
many of
the 6.5 billion people in the world do not know about their ancestral
background or claim to be in another category than their biological
evidence
would prove. These are only a couple of the many arguments that are
displayed
throughout this detailed article. A racial, ethnic, and ancestral
grouping is
just one argument of the many in genetic research that will only be
solved by
time.
This article would make for an interesting class because of the great
diversity that is displayed within our classroom alone. According to the
University of Texas at Austin Office of Institutional Research Office,
only
57.4 percent of the fall 2005 student body claimed to be white. Meaning
that
over 40 percent of the student body is of some other ethnic race. I
believe
that this article will be interesting to all races because of the
racial and
ethnic stereotypes that are placed among the students everyday. Racial
and
ethnic backgrounds play important roles of each individual in the
classroom and
it would be interesting for the students to relate their genetics class
to their
lives. The classroom should be a place where we become more
knowledgeable about
what is going on in the outside world and this article can stimulate
one’s
desire to research and find out more about human genetics research and
the
effect it plays on racial and ethnic discrimination. The article states
that
“as the complex origins of human traits, behaviors, and diseases slowly
are
unraveled, how genetics research is conducted could influence whether
racial
and ethnic discrimination increases or decreases over time.” I also
believe
that if the question of whether or not racial, ethnic, or ancestral
categories
be used in human genetic research be raised in the classroom; there
would be a
great discussion or even a debate over this topic.
Other interesting topics are also found in this article. Including a
short
history of the first anatomically evolved human and its origin, how
humans are
genetically less diverse than one another compared to other mammals,
and the
reason for some physical differences within each group.
A
study of identical twins’ palmprints for personal verification, Adams
Wai-Kin
Kong, David Zhang, and Guangming Lu, Pattern Recognition, Volume 39
Issue 11,
Pages 2149-2156, 11 April 2006.
This article is about a study made on biometrics and identical twins.
Many
identification problems arise with the inability to distinguish
biometrics in
identical twins. Twins are not easily distinguishable in court, twins
can use
their gift in crimes like fraudulent insurance compensation, and twins
can
easily sneak in and out of places pretending to be one another. All
these
problems need to be solved with more sophisticated technology for
biometrics.
The study examined palmprints from the same DNA to uncover genetically
related
palmprint features. The conclusion was that palmprints contain
genetically
related features as well as genetically unrelated ones that can be used
for
classifying identical twins.
I have a special interest in this kind of study because I myself am an
identical
twin. My sister and I recently participated in a similar study
currently being
conducted in the UT psychology laboratory and are eager to find the
results
from that study. Identical twins are mind-boggling in that they provide
an
excellent opportunity for researching the nurture vs. nature debate
that has
been going on forever. What makes us who we are, genetics or the
environment?
This study provides new research in distinguishing twins, which is very
interesting.
Article Title: Mother knows best: Epigenetic inheritance, maternal
effects, and
the evolution of human intelligence
Author: David F. Bjorklund
Journal Title: Developmental Review
Volume: 26, Issue 2
Page Numbers: 213-242
Date of Publication: June 2006
There are numerous theories in the nature vs. nurture debate, but
according to
this researcher, nature and nurture interact with one another to
determine
characteristics. Genes are influenced by the environment, especially
during
early development. Some genes need a certain type of environment in
order to
be expressed. Thus, in different environments there are different
characteristics, and depending on the environment, certain
characteristics will
prevail and evolve over time. These genes include those that express
phenotypes, behavior, and intelligence. One correlation discussed in
particular is how human intelligence is affected by mothering (chimps
raised by
humans show cognitive ability that is more human-like as opposed to wild
chimps).
This raises numerous questions that may not get as much attention as
deserved.
How much depends on the environment in natural selection in the
evolution of
mankind, as opposed to the ability of a person’s genes to adapt and
change in
certain environments? With this outlook on development, natural
selection
becomes a matter of the “survival of the fittest genes”. Also, how do
parents
deal with knowing their child has a certain “bad” gene that has a
possibility
of being expressed? These genes could include a possibility for
homosexuality
or even psychological disorders such as depression. Do parents set up an
environment that discourages “bad” genes from developing, and will that
tactic
actually work? Lastly, to what degree do certain characteristics owe
their
evolutionary change to the environment? It seems as though some
characteristics, such as phenotypes, are affected more by the
environment than
others, such as intelligence, and will evolve more quickly.
Different people have different opinions on how the environment affects
the
development of a person and how a person becomes who they are. In the
past,
the environment was never given much credit for this development, and
genes
were given the most attention. But now, as more research is done, new
light is
being shed on the role of the environment. I find the topic very
intriguing
since it deals with how people develop into themselves and how
characteristics
of species, and thus the species themselves, have evolved over time due
to
factors beyond their control (the environment). Although we've already
somewhat discussed this topic in class, I feel that it deserves more
attention
- it would be interesting to hear the different opinions of classmates
on this
seemingly controversial topic.
Genetic and Environmental Influences on Eating Behavior: The Swedish
Young Male Twins Study, Sanna Tholin, Finna Rasmussen, Per
Tynelius, and Jan Karlsson, The American Journal of
Clinical Nutrition, Vol. 81 No.3, p.
564-569, March 2005
The
article unravels the question of whether eating habits is
influenced mostly by genetics or environment by
studying twins of a certain population, Swedish young
male twins. The dimensions of eating behaviors studied and
questioned are cognitive restraint, emotional eating, and
uncontrolled eating.
GENETICS: The Critical Region in Trisomy 21, David L. Nelson and
Richard A.
Gibbs, Science, Vol. 306, pp. 619-621, October 2004.
This article discusses the question of whether triplication of the 33
critical-region genes is directly responsible for the craniofacial
abnormalities of Down Syndrome. The authors discuss a mouse model used
to
figure out whether or not this is true. I think that discussion of this
article
will make for an interesting class because Down Syndrome is one of the
most
common genetic diseases, and affects 1 out of every 700 children.
Therefore,
many of your students probably know people who have been affected by
this
disease, and would be interested in hearing about this.
Genetics of Osteoporosis
Huang, Qing-Yang and Annie Wai Chee Kung
Molecular Genetics and Metabolism, volume 88, pg. 295-306, August 2006
Summary
Osteoporosis is basically a bone disease that causes the bones of
individuals
to become brittle over time ans thus leading to the cumulative fracture
of the
bone itself. This disease has been noticed at a higher ratio if women in
compared to men, especially in post-menopausal women and those over 80.
Osteoporosis is caused by lower and lower Bone Mineral Density, or BMD,
in
which causes the bone to lose bone density and strength over time which
scientists believe to be affected both by the genetics make-up of the
individual as well as the environment that they are placed in.
The two researchers from the University of Hong Kong that posed a
question of
how much of the effects of osteoporosis is based on the genetic
material of
each individual. Overall, the researchers were taking a deeper look on
the
connection of certain genes and linked genes as well to the cumulative
effects
that they cause on the degenerative bone disease. The two researchers
decided
to use both mice and human genome to identify the specific genes that
cause
this disease and if there is substantial connection between these genes
to the
severity it affects the disease. The basic concept behind their
research was
to find any sort of connection between the genetic makeup of an
individual and
the expression of the disease. The research later produced the result
that the
human gene ALOX12 was a significant contributor to BMD degradation.
They also
discovered that certain loci locations on sex-linked genes and in
polymorphism
also account on why women suffer more severely from osteoporosis than
men which
provided proof to the original hypothesis.
I believe that this article is relevant to the current topics that we
are
currently covering in class in that it deals directly to how genetics
affect
the pathogenesis of osteoporosis. The article covers how certain genes
directly affect the individual and whether or not they will suffer
osteoporosis
later on in life. This is another example to the idea of whether or not
genetics affect either the personality and physical status of people
such as in
homosexuality to diseases such as cancer. It asks the question of
whether genes
or the environment has more effect on osteoporosis or maybe caused by a
factor
or both in equal say. Therefore, the researchers performed an
experiment in
which they mapped out certain suspicious genes and that they suspected
to cause
the disease in mice and humans and then compared the results. This
experiment
was actually performed very thoroughly using strong inference in that
they knew
exactly which genes to look at for both species and even carried out
gene
mapping cases between males and females as well as in twins. After all
the
experiment and mapping of genes the researchers realized that it was
indeed
certain regular and sex-linked genes that account for low BMD ratios in
certain
individuals. With clean experiments and certain results they decided
that women
were more susceptible to osteoporosis, there was a higher chance in
twins to
both get osteoporosis if one had certain genes, and that the disease is
much
more dependent on genetics makeup than the environment in that the
disease is
also dependent on foods consumed and activities of the individual. I
believe
that this article will prove to be very interesting for the class in
that it is
a modern day and pretty recent research experiment that was performed
using
concepts of strong inference directly involving the major concepts of
genetics
in studying certain genes that cause diseases in people. It is
basically a
real life example of all the points that we have covered in the class.
“Single nucleotide polymorphisms in DNA repair genes and basal cell
carcinoma of
skin”
Ranjit Kumar Thirumaran, Justo Lorenzo Bermejo, Peter Rudnai, Eugene
Gurzau,
Kvetoslava Koppova, Walter Goessler, Marie Vahter, Giovanni S. Leonardi,
Felicity Clemens, Tony Fletcher, Kari Hemminki and Rajiv Kumar
Carcinogenesis, vol.27, pp.1676-1681, February 25, 2006
Every year thousands of Americans are affected by various skin cancers,
and the
most common form of skin cancer is known as basal cell carcinoma or
BCC.
People generally correlate skin cancer with excessive exposure to UV
radiation,
but that is not the only factor that influences the individual
susceptibility to
BCC. Genetic factors also play important roles. Functional repair
enzymes are
needed to remove the photoproduct formed by UV exposure in the DNA of
skin
cells, and to repair the broken strands that consequently occur.
Individuals’
susceptibility to skin cancers, including BCC, varies directly with the
repair
capacity of their DNA. In this article, the researchers specifically
want to
determine the risk modulation of BCC by variant allele for T241M
polymorphism
in XRCC3 gene and gender specific effect by E185Q polymorphism in NBS1
gene.
I think this article would make an interesting topic for the class
because it
presences another case between the debate of nature and nurture. Many
people
believe that skin cancer is strictly caused by environmental factors,
such as
exposure of UV radiation. However, the result of this research indicates
otherwise. The results of the study do not show a statistically
significant
correlation between the amount of sun exposure and risk of BCC. On the
contrary, they show that carriers of variant T-allele for T241M
polymorphism in
XRCC3 gene have a statistically significant decreased risk of BCC.
Also, I
thought it would be interesting for the class to see that the risk of
BCC is
different in each gender due to the variant allele in a gene.
Neuromedin ß: a strong candidate gene linking eating behaviors and
susceptibility to obesity
Luigi Bouchard, Vicky Drapeau, Véronique Provencher, Simone
Lemieux, Yvon
Chagnon, Treva Rice, DC Rao, Marie-Claude Vohl, Angelo Tremblay, Claude
Bouchard and Louis Pérusse
The American Journal of Clinical Nutrition
Vol. 80, No. 6
Pp 1478- 1486
September 2, 2004
The obesity epidemic has become one of the most important public health
problems
of our generation. During the past 20 years, there has been a dramatic
increase
in obesity in the United States. The recent increases in the prevalence
of
overweight and obesity are reflected across all ages, racial and ethnic
groups,
and education levels in the U.S. Despite recent advancements in our
understanding of obesity, our capacity to prevent weight gain and to
treat
obesity is still far from adequate. Obesity is frequently associated
with
eating disorders, and evidence indicates that both factors are
influenced by
genetic factors. Although several genes have been shown to be
associated with
obesity, little is known about the genes influencing eating behaviors in
humans, despite evidence that abnormal eating behaviors and disorders
are
frequently encountered in obese subjects. I feel like the objective of
this
experiment, to identify genes associated with eating behaviors, would be
interesting and beneficial to study because it provides information that
directly affects our life and well being in multiple ways.
A relation between eating behaviors and obesity has been suggested in
multiple
studies, but there is also evidence that these behaviors are governed by
genetic factors. Persons who binge eat or who have bulimia nervosa or
anorexia
nervosa are also characterized by dysfunctional levels of cognitive
dietary
restraint, disinhibition, and susceptibility to hunger compared with
normal
subjects, and they also have an important heritability component.
Despite
the fact that eating behaviors are partly heritable traits, little is
known
about the genes influencing them.
The Quebec- Family Study is designed to investigate the genetics of
obesity.
Three eating behavioral traits, cognitive dietary restraint,
disinhibition, and
susceptibility to hunger were assessed with the use of the Three-Factor
Eating
Questionnaire. In the Québec Family Study (QFS), disinhibition
and
susceptibility to hunger were positively associated with BMI, body
fatness, and
waist circumference. To confirm or provide new quantitative trait
linkage
analyses, to identify the genes influencing the eating behaviors, and to
provide new chromosomal regions, a genome-wide scan linkage analysis was
undertaken in the Quebec Family Study. Taking into account body
composition
and macronutrient and energy intakes, a genome-wide scan was conducted
with
genetic markers spanning the 22 autosomes to identify quantitative
trait loci
for eating behaviors. Two approaches were used to test for linkage
between
eating behaviors and the genetic markers. Linkage was tested with the
Haseman-Elston regression-based sibpair linkage procedure as well as
with the
variance components based approach. Genome-wide linkage analyses
provide an
opportunity to identify chromosomal regions that harbor genes
influencing
complex traits, such as eating behaviors. Using this approach, four
quantitative trait loci were identified for disinhibition and
susceptibility to
hunger while no evidence for linkage was found for cognitive dietary
restraint.
Genetic associations were assessed by analysis of covariance comparing
mean
phenotypic values across Neuromedin Beta genotypes. The results of this
experiment suggest that Neuromedin Beta is a very strong candidate gene
of both
eating behaviors and predisposition to obesity.
Association of GABRA2 with Drug
Dependence in the Collaborative Study of the Genetics of Alcoholism
Sample
Behavior Genetics: Volume 36, Number
5/September 2006. Pgs 640-650.
Authors:
Arpana Agrawal, Howard J. Edenberg, Tatiana Foroud, Laura J. Bierut,
Gerald
Dunne, Anthony L. Hinrichs, John I. Nurnberger, Raymond Crowe, Samuel
Kuperman,
Marc A. Schuckit, Henri Begleiter, Bernice Porjesz and Danielle M. Dick
Description:
This study focuses on a series of twin studies that found certain
genetic
factors to be influential on alcohol and illicit drug dependence. It
explores
the relationship between GABRA2 and illicit drug dependence in the
Collaborative Study on the Genetics of Alcoholism with two goals in
mind. Genes
in the GABAA receptor gene cluster on the 4p3-12 are to be examined in
order to
determine whether they are associated with marijuana and other illicit
drug
dependence. In addition, the extent to which the association between
these
genes and alcohol dependence varied according to the individuals with
co-occurring drug dependence will be examined.
In 2003, approximately 20 million Americans ages 12 + were illicit drug
users.
Family studies have shown that drug disorders cluster in families and
that
relatives of individuals with drug problems are at a higher risk of
having drug
problems themselves. This is an important topic that relates to several
individuals our age. Not only is it interesting, but this article also
relates
to what we our learning in class in relation to nurture vs. nature.
"Isolation of a human gene that inhibits HIV-1 infection and is
suppressed by
the viral Vif protein"; Ann M. Sheehy, Nathan C. Gaddis, Jonathan D.
Choi and
Michael H. Malim; Nature 418, 646-650 (8 August 2002)
Many viruses develop ways to overcome host-mediated mechanisms that
prevent the
viruses from being infectious. HIV-1 is a virus that codes for a
protein called
Vif (virion infectivity factor) and this protein is necessary for it to
replicate and infect other cells. Human T lymphocytes have an innate
antiviral
phenotype (via gene, CEM15) which is inactivated by this Vif protein.
The
question then arises that if the production of Vif protein is
interrupted,
could the CEM15 antiviral phenotype help fight the infection?
This article is interesting in that it investigates the DNA's innate
ability to
fight off viral infections and how HIV is able to overcome these natural
defenses by producing a specific protein. Being a regulatory circuit,
it also
reinforces the idea of the protein inhibition of genes, i.e. gene
expression.
Also this research could spawn discussion over other viruses and
whether they
behave in a similar way.
Fluctuating asymmetry in certain morphological traits in laboratory
populations
of Drosophila ananassae
Vishalakshi C, Singh BN
GENOME 49 (7): 777-785 JUL 2006
In this article, the authors were mainly interested in finding out about
fluctuating asymmetry in Drosophila ananassae. Is it caused by genetic
or
environmental factors? Are they more frequent in certain populations?
Are
females more prone to fluctuating asymmetry than others? They also
focused on
fluctuating asymmetry in five certain traits to see in which
populations or
which sex they were more frequent. This would make for an interesting
lecture
because it discusses nature vs. nurture while also exploring the
differences
between the sexes and their susceptability to genetic influences and
environmental factors.
Three allele combinations associated with Multiple Sclerosis, Olga O
Favorova 1,2, Alexander V Favorov 3, Alexey N Boiko 4, Timofey V
Andreewski 2, Marina A Sudomoina 1,2, Alexey D Alekseenkov 2, Olga G
Kulakova 1, Eugenyi I Gusev 4, Giovanni Parmigiani 5 and Michael F Ochs
6, BioMed Central Medical Genetics 2006, Volume 7, 1-9* (Online
Article, no page numbers given), 26 July 2006.
This
article can be best described as one that does not pose a question, but
rather one that discusses the complexity genes in our body. This
article discusses the illness is MS or Multiple Sclerosis and
how it
can be in ones genes to get this illness at some point in their
life.
The difficulty in identifying whether or not the disease is genetic in
yourself is due to the fact that there are so many gene combinations
that could be causes for the disease. We do not know whether it
is one
group of genes or many different groups of genes that make up
whether
or not someone can get MS. This particular article discovers 2
new
combinations that can be the cause of someone getting MS through their
gene pool. In class we have brushed upon the
idea that alleles are alternative forms of certain genes, and this
article gives a real world example of how dominant and recessive genes
work. This article also would be interesting in class because it
gives
students who are Pre-med, or Pre-health in general a glimpse into the
kinds of scientific literature they will have to read
and learn about
in order to become the future doctors, researchers, dentists,
pharmacists, etc of the future. It also is a good article for
people
who are studying biology to become scientists, because you get a chance
to learn about genetics and how it applies to humans, as well as
getting a better understanding of how genetics works in terms of our
health. This article is also interesting because it helps to see
how
genes work in the human body in general, it would help to understand
why it is that our hair colors or our eye colors are what they are.
“Genetics: A Genomic View of Animal Behavior,” Elizabeth Pennisi,
Science, Vol.
307, pages 30-32, January 7, 2005.
This article asks many questions concerning the link between genetics
and
animal behavior. Though animal behavior is already studied by
evolutionists
and other biologists, what role does genetics play? Is a certain animal
behavior stimulated by a cue from their environment, a complex
interaction
between genes, or both? Also, how does a particular gene operate in
several
different species—does it influence generally the same behavior or
something
completely different? What other behaviors does one gene influence? How
many
genes influence one behavior? These last three questions were pivotal in
several experiments the article discussed, which include: how an
unidentified
gene (dubbed forager, which codes for a protein called cGMP-dependent
protein
kinase (PKG)) controlled how much a fruit fly wandered and how readily
they
responded to sugar, and also how the same gene proved key to feeding
behavior
in other invertebrates as well; how researches used microarrays to look
at the
differences that distinguish bees that tended the hives from bees that
left the
hive for pollen, and found 2200 out of 5500 genes examined whose brain
activity
varied between the two different bees; and how if any component in the
“micronetwork” that causes a mouse to be able to recognize other mice
it is
familiar with is removed, then the mouse loses its ability to tell a
familiar
mouse from a stranger. Many other experiments were discussed in the
article,
including the genetic basis for the presence of studs and social
outcasts among
male chichlids. Another question posed in the article was if the way
genes were
regulated was just as important as the proteins they produced, in the
instance
of the prairie vole, which is faithful to its mate, and meadow voles,
which are
not. Larry Young of Emory University found that a regulatory region was
longer
in the monogamous species, and when he put the prairie vole’s
vasopressin (the
neuropeptide governing this trait) receptor gene and its regulatory
region in
mouse embryos and meadow voles, both became more faithful than typical.
Lastly, Michael Meaney from McGill University found that a different
regulatory
region, called a promoter, is pivotal in the social relationship
between parents
and their offspring, and demonstrated that when a mother rat fails to
lick and
groom her newborn pups, chemical changes in DNA bases make those pups
grow up
timid and abnormally sensitive to stress.
As an Evolution, Ecology and Behavior major, I find this article very
interesting and useful, especially since it tries to link genetics to
several
other areas of Biology. As said in the article: “ ‘There is this clear
gulf
between people who are using modern genetic techniques to study very
specific
questions and the people who are studying natural diversity,’ adds
Steve Phelps
from the University of Florida, Gainesville. But as more behavioral
scientists
take up the tools of genomics and comparative biology, the payoff may
be a
deeper understanding of the molecular basis of behavior in animals--even
people--and how behaviors originally evolved. The field ‘is very ripe
for a
productive synthesis,’ says Phelps.” This article is a great example of
how
genetics can solve certain mysteries other areas of Biology are having,
and how
“crosstalk between disciples” can help clear up some of these
mysteries.
Title: Genetically modified crops: success, safety, assessment, and
public
concern
Authors: Om V. Singh, Shivani Ghai, Debarati Paul, and Rakesh K Jain
Journal: Applied Microbiology and Biotechnology Vol 71 August 2006
This article explains what is done to make genetically modified crops.
It
describes the different ways they can insert transgenes derived from
other
plants or organisms into the crops DNA to change some characteristic of
the
crop. This process is becoming more popular and has been widely used in
recent
history but there is still ethical/social dilema. People are concerned
about
what this does to the plants that ultimately end up eaten by humans and
what it
does to the environment. The article lists some of the great positive
results of
genetically modified crops and also the areas in which there is a risk
to people
or the environment. This is a good article because it deals alot with
the
social context and how this technology is regulated by public concern.
The
people are afraid and want to know what is in their food. This
technique could
make even greater advances than are already in place but more research
is
needed to ensure safety to the consumer.
Genetic Covariance Among Measures of Information Processing Speed,
Working Memory, and IQ
M. Luciano, Behavior Genetics, Volume 31, pgs 581-592, November 2004
This
article describes a study which aims to settle the heated debate
between nature and nurture's role in intelligence. Is
intelligence a
gift handed down from parents or is it something earned through
lifetime experiences? If intelligence is indeed genetic, then
where in
our DNA is it coded? With this exciting research, along with many
recent advancements in genetic engineering, perhaps a more intelligent
human race can be created. Furthermore, if intelligence is not
derived
from our genes, what creates the variation in intelligence? More
research can be done on shaping the young minds of children into more
intelligent adults. The study performs extensive tests on sets of
identical twins. The measures of IQ are separated into
information
processing speed, working memory, and complex cognitive processes, in
order to assess individual parallels between subjects. The
results of
the study show strong correlation between genotype and performance on
nearly all three tests.
"The use of cDNA
microarray to identify differentially expressed
labor-associated genes within the human myometrium during labor"
M. Sean Esplin
MD et al
American Journal
of Obstetrics and Gynecology
Volume 193,
Issue 2 , August 2005, Pages 404-413
This
article asks the question: What genes are expressed only in humans who
are in labor? In other words: Which are the labor-specific genes?
<>The
researchers used cDNA microarray technology to identify those genes
differentially expressed during labor, and then used multiple methods
for confirmation: RT-PCR, Northern blot, and in-situ hybridization.
<>
<>
Effect of Limited DNA Methylation Reprogramming in the Normal Sheep
Embryo on Somatic Cell Nuclear Transfer, Nathalie Beaujean, BioOne, pp.
185-193, Published March 1, 2004
The demethylation of cytosine in the sperm genome before a functional
zygote is formed is thought to be an important function of the oocyte
cytoplasm for subsequent embryonic development in the mouse. This event
does not occur in the sheep or rabbit zygote and occurs only partially
in the cow. The aim of the study was to investigate the effect of
limited methylation in the normal sheep embryo. Sheep fibroblast
somatic nuclei were only partially demethylated and underwent a
stepwise passive loss of DNA methylation during early stages. Our
results suggest that somatic nuclei that do not undergo rapid
reorganization of their DNA before the first mitosis fails to develop
within two to three cell cycles. However, because only embryos with
certain chromatin appear to survive the morula stages, failure to
demethylate the cells of the blastocyst is likely to directly impact on
developmental potential by altering programmed patterns of gene
expression. Thus, remodeling of DNA appears critical for development of
both fertilized and nuclear transfer embryos.
I think this would be a great article for our class because we spoke
about methylation being an indication for the expression of certain
proteins. In this case demethylation is occuring for growth and
developmental reasons.
Genetic Influences on Female Infidelity and Number of Sexual Partners
in Humans: A linkage and Association Study of the Role of the
Vasopressin Receptor Gene (AVPR1A)
Lynn F. Cherkas, Elizabeth C. Oelsner, Y.T. Mak, Anna Valdes, and Tim
D. Spector
Twin Research
Volume 7 Number 6
pp. 649-658
December 2004
This article examines a research study where 1600 randomly-selected
female twin pairs from the United Kingdom confidentially reported their
experience with unfaithfulness, their attitudes towards their
infidelity, and their total number of sexual partners. The purpose of
the study was to determine if infidelity and sexual promiscuity are
heritable or affected by environmental influences, and if they are
associated with the vasopressin receptor gene, a locus implicated in
other mammal’s sexual behavior. The results showed that variation in
infidelity and in the number of sexual partners can be explained by
genetic variation with little or no role for environmental factors, and
that they do have a heritable component. For example, identical twins
are approximately one and one-half times more likely to be unfaithful,
if their twin is unfaithful. However, attitudes towards infidelity were
explained mostly by environmental influences. Also, the analysis did
not support the hypothesis that the vasopressin receptor gene could
explain variation in human sexual behavior. In addition, the article
talks about how this supports evolutionary theory that promiscuous
sexual behavior is advantageous for women and is part of a selective
evolutionary process.
I believe this article will be interesting for class discussions
because it addresses the correlation between psychological behavior and
genetic influences. Most of us consider sexual promiscuity to be an
environmental factor; however, this study forces us to reexamine our
preconceptions.
Can random mutation mimic design? A guided inquiry laboratory for
undergraduate
students, Steven T Kalinowski, Mark L Taper, and Anneke M Metz,
Genetics 2006;
Volume 173, Issue 4, August 2006, published ahead of print on September
1, 2006
The main goal of this paper is to explore the question and simulate a
possible
answer of whether random mutation can create complex biological
structures that
appear designed by using paper airplanes as the model organism. Some
structures
in living organisms seem so complex and therefore have been said to be
evidence
of intelligent design. The purpose of the guided lab is to investigate
evolution by using a paper airplane and also to invoke scientific
thinking.
I think this would be a good article for the class because it is brings
into
play many difficult ideas and questions about human evolution and the
ability
of random mutation yet creates a more simple method for answering them.
The
paper airplanes serve as a great model organism because the “fitness”
of each
plane, shown by the distance it flies, is a task of its ability to
mutate
independently. Those that are built best (by random changes made in its
structure) fly farthest, and those that fly farthest model those that
are able
to reproduce sucessfuly by selection. The guided lab is useful in
teaching
students for themselves how natural selection works is a good
introduction to
understanding how complex adaptations can evolve.
Appetite Control, Katie Wynn, Sarah Stanley, Barbara McGowan, and Steve
Bloom,
Journal of Endocrinology, Vol. 184, 291-318, 2005.
In the last decade our body weight and food intake has increased
immensely
as well as our understanding of the physiological systems. Our bodies
transfer
different signals via neuropeptides which regulate energy homeostasis.
For
example, insulin and hormones have a great effect on influencing our
body
circuits. This review discusses central neuronal networks and different
signals which contribute energy homeostasis, and how a loss of the
homeostatic
process may result in obesity. However, it has been argued that
evolutionary
pressure has resulted in a drive to eat with out limit when food is
readily
available.
Our bodies must continually balance food intake with energy expenditure.
Many hormones initiate and terminate a meal. I think that this article
is
extremely interesting because Americans are overweight and it is
partially due
to the way they treat themselves on the inside and the outside. A proper
nutrition starts on the inside of the body with knowledge of ones own
hormones
and how energy homeostasis takes place. When an individual understands
how his
or her own body works then they might think different about what they
put into
their bodies.
I am also very interested in diet and appetite control because as a
woman
at The University of Texas I have witnessed first hand how other women
have an
appetite that is out of control, or on the other hand no appetite at
all. I
think if we could reach out to them with something that may make them
reconsider the lettuce they eat three times a day, or the triple
cheeseburger
that they eat at three in the morning, women may have a better
understanding of
appeite.
Genetic mapping of a 17q chromosomal region linked to obesity
phenotypes in the
IRAS family study, BS Sutton, CD Langefeld, JK Campbell, SM Haffner, JM
Norris,
AL Scherzinger, LE Wagenknecht, DW Bowden, International Journal of
Obesity, 30,
1434-1441, 7 March 2006
Obesity is a complex disorder that affects a significant percentage of
the US
population. “Although the environmental changes in the industrial world
(i.e.
food intake, sedentary lifestyles, etc) are often blamed for the overall
increase in this epidemic, an individual’s genetic susceptibility is
also a
major contributory factor” (BS Sutton et al, 1434). In this article, a
research conducted explores DNA samples of a group and the regions on
their
genomes that contribute to an unknown “obesity gene.” “A major aim of
the IRAS
Family Study is to identify chromosomal regions and specific candidate
genes
associated with obesity-related traits in two ethnically diverse
cohorts:
Hispanic and African Amerian” (1434). Information taken from the
subjects that
underwent the study include six primary obesity phenotypes, including
BMI, waist
circumference, waist-hip ratio, VAT, SAT, and visceral –subcutaneous
ratio.
Blood samples taken from the subjects were then analyzed. Through
genomic
mapping, chromosome 17q was linked to three of the obesity phenotypes
thus
relating a specific chromosome to the “obesity gene.”
I think this article would be interesting for class because so much can
be
speculated about the different causes of obesity. This article provides
an
alternative and proven answer to the cause of obesity through genetics.
Since
the results show that obesity is linked to a specific chromosome,
thought
provoking explanations can be speculated on different approaches of
treating
obesity.
Article Title:
Gene therapy that inhibits NF-.B results in apoptosis of
human hepatocarcinoma by recombinant adenovirus
Authors' names:
Tie-Jun Li, Li-Ping Jia, Xiao-Ling Gao, Ai-Long Huang
Journal Title:
World Journal of Gastroenterology ISSN 1007-9327
Volume: 12
Page Numbers:
5287-5292
Date of
Publication: September, 7, 2006
The question being asked here is whether or not the recombinant
adenovirus
induces
the TNF-a-mediated apoptosis in vivo. The reason why I believe it will
be interesting for the class is because it applies genetics into
researching whether or not genetic material is capable of helping us
create a potential treatment for liver cancer. This article is well
organized and detailed enough to help us understand what they have
done.
Genetics of cattails in radioactively contaminated areas around
Chornobyl., Tsyusko, O., Smith, M., Oleksyk, T., Goryanaya, J., &
Glenn, T., Molecular Ecology, Vol. 15 (9), pp. 2611 - 2625, August 2006.
Article Title: Restriction
of vaccinia virus replication by a ced-3
and ced-4-dependent pathway
in Caenorhabditis elegans
Authors NamesWan-Hsin
Liu,Yi-Ling Lin, Jia-Pey Wang, Willisa Liou, Roger F. Hou, Yi-Chun
Wu, and Ching-Len Liao
Journal Title: Proc Natl Acad Sci U S A
Volume:
103
Page
Numbers: 4174–4179
Date of
Publication: Online 2006 March 6
I find these
article extremely interesting because these C.elegans are almost
completely
resistant to viral attack. The C. elegans can however be susceptible to
bacterial infections, yet viruses seem to do nothing to them. There is
a huge
evolutionary gap between the C.elegans and the mammals of course, but
it is
interesting since 19,000 of the C.elegans proteins have matches in
humans,
which is greater than 40% of their protein make-up. In this
study, the
question arises wether or not C.elegans can be further extended as an
artificial host for animal virus infections.
How could the
machinery of the the C.elegans be responsible for not allowed viral
infections?
They scientist turned to something called VV, which is vaccine
virus. The
VV can find it’s way into the machinery of SOME C.elegans, but not all.
The scientist had to ask the question of why this is. Wild type
N2 strain
of C.elegans cannot be infected with the VV virus. PEG is something
that can
help a virus interact with a host cell and allow the virus to enter
inside the
cell walls. They used multiple types of staining methods and
incubation
times with the PEG and the VV viruses to see if the genome of the VV
virus
would penetrate the host cell. They tagged the VV virus with X-Gal for
signs of
it inside of the host cell. What was odd is that the genome of the VV
virus did
invade the host cells cytoplasm(which is where it normally replicates),
yet
something was still prohibiting the virus from forming progeny. So now
they
have ruled out the possibility that there is something in the
extracellular
matrix that might not be allowed the virus to replicate.
There must be
something in the genes of the C.elegans
that is prohibiting the virus from replication. C. elegans have
PCD just like human cells have. The
program cell death genes in C.elegans
are ced-3,ced-4, ced-9, and egl-1. The scientist then weakened or
turned
the genes off in the C. elegans
and all of a sudden, a sudden rise in the population of the
C.elegans
was seen. Something at the
genetic level was inhibiting the forming of the viruses in the cells
even
though they were sitting right there in the cytoplasm. We show
here that the ced-3, ced-4, ced-9, and egl-1 genes, composing the core
PCD
machinery, control VV replication inside C.
elegans. In addition, the effects of ced-3 or ced-4 mutations on the
cell-killing
activity and VV replication levels in worms appear to be closely
associated..
<>This is a very brief summary of what is discussed, and
I think this would be a fascinating subject to continue studying more
in depth
in class. This takes a look at the genetic level, a organism which can
resist
viral attacks! I think it goes unsaid the possibilities of the secrets
of the
genome of C. elegan that is to
be had. This flows with this classes material, because it looks at
individual
genes on the genome.
Title: HLA-B Maternal-Fetal Genotype Matching Increases Risk of
Schizophrenia
Authors: Christina G. S. Palmer, Hsin-Ju Hsieh, Elaine F. Reed, Jouko
Lonnqvist,
Leena Peltonen, J. Arthur Woodward, and Janet S. Sinsheimer
Journal: The American Journal of Human Genetics
Volume: 79
Pages: 710-5
Electronic publication: 8/15/06
QUESTIONS ASKED:
- What are the primary risk factors and causes of schizophrenia?
- Are the causes more due to the genetics of a person or by the
environmental
influences?
- Do the birth complications associated with schizophrenia originate
from
genetics influences also?
- Is HLA matching a risk factor in the development of schizophrenia?
HIGHLIGHTS OF ARTICLE:
- Schizophrenia heritability appears to be more due to genetics (81%)
than
environmental causes (11%).
- The environmental affects that causes schizophrenia would most likely
occur
very early in life (prenatal).
- Pregnancy complications are considered to be highly involved as being
risk
factors of schizophrenia. These complications may even originate from
genetics
also.
- Rh (Rhesus) incompatibility is a complication that has a strong link
to
schizophrenia.
- Maternal sensitization has occurred in healthy pregnancies and may
actually be
beneficial for implantation and maintenance of pregnancy. Some cases in
which
there is HLA (human leukocyte antigen) similarity between the mother
and fetus
have resulted in increases of the risks for fetal loss and other birth
complications and defects.
- Female offspring appear to be more vulnerable to the effects of HLA-B
locus
MFG (maternal-fetal genotype) matching but this may be due to
pre-eclampsia, a
condition associated with HLA-B matching. Female fetuses have a higher
survival
rate than male fetuses in pre-eclampsia which is why the effects of this
condition on schizophrenia may be observed more on females.
OPINION:
I find this article to be very intriguing because I have always been
interested
by schizophrenia and its origination. If this disorder is really caused
by
one's genetics as how the article had implied, then steps may be taken
toward
finding a solution to prevent the risk factors from ever occurring to
the
fetus. Even if a solution may not be reached yet, just being able to
forewarn a
family of the possible risks of schizophrenia for their child will help
to
prepare them mentally for that possibility. I must admit that I did not
completely understand all of the experiment's statistics and resulting
data and
that why I do hope that we will discuss this article in class so that
you can
further explain the details of the article's findings.
Title: Genetically modified crops: success, safety assessment, and
public concern
Authors: Om V. Singh, Shivani Ghai, Debarati Paul, Rakesh K Jain
Journal Title: Appl Microbiol Biotechnol
Volume: 71
Pages:598-607
Published: 26 April 2006
This article raises several questions regarding the advantages and
dangers of using genetic engineering in the agricultural industry. One
such advantage discussed in the article is the reduction in crop
production cost, and the increase in crop yield. These advantages are
due to use of genetic engineering to lead to a drop in pesticide use
and an increase in the general heartiness of crops. One interesting
point that the authors made was that a decrease in pesticide use, due
to genetic modification, would not only reduce cost to farmers, but
also reduce the amount of toxic chemicals placed into the
environment. Another question which was raised was the
possibility of genetic modification leading to easy mass production of
plant based biopharmaceuticals such as edible plant vaccines. The
article goes on to discuss several other types of biopharmaceuticals
such as monoclonal antibodies(MAbs), enzymes, blood proteins, and new
types of subunit vaccines which could be mass produced safely, and at a
low cost using genetic modification on crops. A final advantage which
the authors raise questions about and analyze is the possibility of
using genetically modified plants for environmental monitoring and
remediation. A point raised by the authors of this article
regarding the dangers of using genetic modification in crops is what
detrimental effects would occur on nontarget species and the
environment. One such danger of using genetic engineering in the
agricultural industry that this article discusses is the introduction
of allergenic or harmful proteins into foods. In the article an
experiment is discussed in which humans who are ileostomists were found
to have modified DNA present in their digestive system from early
consumed genetically modified crops. In this regard the authors raise
the question if animal testing would be used to see if genetically
modified crops have any toxic effects. The authors also point out that
DNA from degraded plants could possibly find their way into foreign
plants, giving these nontarget plants an unintended phenotype. Another
danger of genetic engineering which the authors discuss is the possible
loss of biodiversity. This could happen by the modified plant
outgrowing the local flora. A third danger discussed by the authors is
the possibility of pests developing resistance to genetically modified
plants. This could occur due to the intense selection pressure on pests
and pathogens populations. A final question raised by this article is
that if governments around the world are doing enough to control
genetic engineering in the food industry. The reason that I believe
that this article would make for an interesting class is that with the
growing organic industry it is necessary to discover whether or not any
significant differences, regarding health and safety, exist between so
called organic nonmodified produce purchased at an establishment such
as whole foods market or genetically modified produce from a grocer
such as HEB. Also, if so called genetic engineering is found to be safe
and profitable in crops what is the next step? Genetically modifying
cows so that they produce more of the desired cuts of meat? Modifying
chickens so that the majority of their meat is grown in the chest? All
of these situations are still yet to be proven physically possible, but
in the future at what point is the line drawn when it comes to genetic
engineering.
Increased glutathione S-transferase activity rescues dopaminergic
neuron loss in
a Drosophila model of Parkinson's disease. Alexander J. Whitworth,
Dorothy A.
Theodore, Jessica C. Greene, Helen Benes, Paul D. Wes, and Leo J.
Pallanck.
Proceedings of the National Academy of Sciences of the United States of
America. v. 102, no. 22 p. 8024-8029. May 31 2005.
This article seeks to discover the mechanism by which the loss of parkin
function causes neurodegeneration. There have been identifications of
genes
that cause inherited forms of Parkinson's disease. With this
information they
ask what neurodegenerative mechanisms may be relevant to these forms of
Parkinson's disease. They propose that parkin is required to prevent
degeneration of a subset of DA neurons in the breain, that this
degeneration is
enhanced by a loss-of-function allele of GstS1 gene and that the
overexpression
of this gene prevented DA neuron degeneration in parkin mutants. With
these
observations they also suggest that compounds known to induce
glutathione
S-transferase expression may provide therapeutic benefits for
Parkinson's
disease.
This article would make for an interesting class because this article
proposes
possible mechanisms by which some forms of Parkinson's disease act and
function. Most people have had heard of Parkinson's disease and have
had some
contact with it. This disease is also currently incurable. In this
article it
is explained how Parkinson's affects our body as well as possible ways
that
this occurs. It is also interesting because with these mechanisms it is
possible, and shown in the experiment, that the effects of Parkinson's
disease
can be slowed. The work also challenges what was considered an absolute
requirement for a certain type of Parkinson's. I would think that this
sort of
article would be interesting because it shows the effects of
Parkinson's,
possible ways it occurs, and possible treatments for the disease.
Consistency of genetic inheritance mode and heritability patterns of
triglyceride vs. high density lipoprotein cholesterol ratio in two
Taiwanese family samples, Kuo-Liong Chien, Hsiu-Ching Hsu, Ta-Chen Su,
Chi-Yu Yang, and Yuan-Teh Lee, BMC Genetics, volume 4, published online
April 23, 2003, link:
http://www.pubmedcentral.gov.content.lib.utexas.edu:2048/articlerender.fcgi?artid=155683
The
question being asked is whether there's consistency in the mode of
heritance and genetic components of TG/HDL-C between 2 different
populations in Taiwan. It was also questioned whether shared
environmental factors would affect in controlling TG/HDL-C. I
just
thought the article was interesting when there was a difference in how
genetic heritability play a more significant role in TG/HDL-C within a
younger community-based family than compared to older hospital-based
family. In hospital based family, shared common household effects
and
high spouse correlation were found significant. This implied that
common household factors might play important roles in TG/HDL-C values
in older age. The study found that age-differential gene effect
might
be responsible for TG/HDL-C varience in different populations.
The
trait can be influenced by various environmental lifestyle risk
factors. I think that we should study other factors that affect
existing defects. Its a never ending process but with each new
information obtain, we can decrease the risks.
New
Insights into Migraine Pathophysiology, Sanchez-del-Rio M, Reuther U,
and Moskowitz MA, Current Opinion in Neurology, volume 19, pts 294-298,
June 2006
This
article proposes new findings in migraine research that mainly focuses
on mutations with “familial hemiplegic migraine and the role depression
in its pathopsysiology and cortical spreading treatment.” The recent
findings of numerous point mutations have led the authors of this
article to believe that migraine may be caused by paroxysmal
interruptions in the ion-translocating method. These mutations make the
brain more likely to “prolonged cortical spreading depression”, which
is the result of “excessive synaptic glutamate release, decreased
removal of glutamate and potassium from the synaptic cleft, or
persistent sodium influx”. Stopping the “cortical spreading depression”
has been a point of concern as far as migraine prevention. Migraines
treated with “beta-blockesrs, valproate, topiramate, methysergide or
amitriptyline” lowered the “cortical spreading depressions in rats.”
Studies with migraine patients also show that the appearance of
cortical spreading depression as a “mechanism”. Many waves of “cortical
spreading depression” in a row can also have negative effects on a
patient’s brain and can cause “silent ischaemic lesions” in specific
regions of the brain “such as the cerebellum”.
So
basically, there are several characteristics of migraine that show
paroxysmal interruptions “in neuronal and vascular function”. This,
therefore, show the disturbances in the regulation of ionic gradients.
This article is interesting to me because I suffer from migraines and
they also are very prominent in my family. It is something that I deal
with on a weekly basis and a condition that I am currently taking
medication for.
Gene Silencing in Cancer in Association with Promoter Hypermethylation
Authors:
James G Herman, M.D., and Stephen B. Baylin, M.D.
Source:
New England Journal of Medicine, Vol. 349, No. 21, pp. 2042-2054,
November 20, 2003
Genetics answers questions on the origins of life; how all living
organisms adapt and reproduce by means of constant evolution. As
fundamental to the creation of life from DNA to RNA to protein, is
inevitable carcinogenesis; the evolution of cancer.
This article explores the mechanisms of cancer outside of the widely
accepted etiology of base-pair mutations in primary DNA sequences.
In the context of genetic evolution, as DNA has the intrinsic
ability to replicate itself, it also has the ability to pass on genes
of cancer susceptibility. The question is to what extent does
gene silencing play a role in cancer development.
Epigenetic changes, occurring independent of primary nucleotide
sequences, to promoter sequences by DNA methyltransferase silences a
gene by methylation. As we know, the human genome is nearly 97%
methylized and not transcribed. In this respect, abnormal
methylation results in cancer development in any of two
ways. Key genes essential for tumor suppression are
methylized, or normally methylized DNA in noncoding chromatin become
unmethylized. Oncogene transcription as a result from
abnormal unmethylization is a known cause of cancer.
Conversely, the article focuses on hypermethylation of
promoter sequences of tumor suppressing genes and this as
a mechanism of an inherited, epigenetically
produced pathology. Further understanding of the role
of promoter sequence methylation has expanded treatment options for
patients diagnosed with cancers of these origins. These key
elements to one of the most pervasive pathologies are explained to
great length in this journal article as are the implications of
basic genetic components in relation to cellular homeostasis.
Designing Babies: A Eugenics Race with China?
By Eric G. Swedin
Futurist, Vol. 40, Issue 3, pp. 18-21, May/June 2006
This article is about accelerating the evolution process through
engineering of the human genome. The article raises the
questions: Is
it wrong that China is removing children with birth defects in the
population through early detection and abortion? Is it good to
disturb
the natural evolution process? Do we really want everyone to be
engineered to perfection? Will eugenics cause more harm than
good?
I think this article would be good to read in class because it involves
the future of genetics. This article is about altering genes to
create
the "perfect" person. As genetics students, we should know how
what we
learn in class applies to the real world. We need to understand
how
important DNA and genes are, and how they can be altered. Genetic
engineering could happen in our lifetime.
Association study of seven polymorphisms in four serotonin receptor
genes on
suicide victims
Author’s names:
Videtic A, Pungercic G, Pajnic IZ, Zupanc T, Balazic J, Tomori M, Komel
R.
Journal Title:
American journal of medical genetics. Part B, Neuropsychiatric genetics
Volume: 67 issue:1
Pgs: 669-672
Year: 2006
The question posed by this article was whether particular seritonergic
receptor subtypes were associated with suicidal behavior. In this
experiment,
scientists studied if there was an association between the
polymorphisms in the
5-HT receptor genes (1A, 1B, 1F, and 2A) and suicidal behavior on a
sample of
226 suicide victims and 225 healthy control subjects. It was meant to
disprove
that polymorphisms may be a genotype marker predictive of an increased
risk for
suicidal behavior. The results of this experiment could have strongly
suggested
that it is possible to determine suicidal behavior from one’s genes. The
article would be interesting in class because it raises the question-
if we
could predict whether someone was likely to kill themselves, what would
we as a
society do with this information? It would be fascinating to question
and
analyze our society and what information regarding genes as a possible
method
of diagnosing and, more importantly, predicting disease would cause us
to do.
Through the experiment, no statistically significant differences of
geneotype
distribution between the suicide and the control groups were determined
from any
of the tested polymorphisms. The data was again sorted according to
whether the
suicide was violent or non-violent and again no differences were
detected.
However it was determined that the homozygotic genotype TT was present
only in
the group of suicide victims, both violent and nonviolent. The data
seems to
disprove the hypothesis that one’s genes for seritonergic receptor
subtypes
were associated with suicidal behavior.
“Clinicogenetic study of mutations in LRRK2 exon 41 in Parkinson's
disease patients from 18 countries”. Hiroyuki Tomiyama, Yuanzhe Li,
Manabu Funayama, Kazuko Hasegawa, Hiroyo Yoshino, Shin-Ichiro Kubo,
Kenichi Sato, Tatsuya Hattori, Chin-Song Lu, Rivka Inzelberg, Ruth
Djaldetti, Eldad Melamed, Rim Amouri, Neziha Gouider-Khouja, Faycal
Hentati, Yasuko Hatano, Mei Wang, Yoko Imamichi, Koichi Mizoguchi,
Hiroaki Miyajima, Fumiya Obata, Tatsushi Toda, Matthew J. Farrer,
Yoshikuni Mizuno, Nobutaka Hattori. Movement Disorders, Volume 21, No.
8, pg. 1102-1108, 18 April 2006.
This study concentrated on the three identified mutations of the LRRK2
exon 41 in different groups of people with Parkinson’s disease around
the world (18 countries , 5 continents) and how the mutations are
expressed in those groups (phenotype and genotype relationships). For
example, in Caucasian subjects, a certain mutation (G2019S) exhibited a
single-founder effect but did not in Japanese subjects; the I2020T
mutation had a single-founder effect on the Japanese subjects.
Furthermore, most of those with PD also had dementia and psychosis, and
a link could possibly be investigated.
I feel that this study would be interesting in class because there is
much recent interest in the inheritance of neurodegenerative diseases
such as Parkinson’s. On a personal level, many students know of family
members (grandparents, etc.) with PD or Alzheimer’s. With a genetic
link, it could become an inherited possibility later in the lives of
the students and their parents. Understanding the causes also increases
research for possible treatments and prevention. It is also a personal
choice of the individual as to which course of action, if
any, they want to take, especially since genetics are merely
chances and not necessarily a fate or guarantee. I also feel that
the scope of the study was unique. In the melting pot culture of the
University of Texas and America in general, genetic differences are of
interest in different demographics of people. Beyond race, since this
study was done in drastically different areas, it could lead into
inquiries of environmental factors and their effects on Parkinson’s
disease such as diet. Also, the far-reaching distributions of mutations
could lead to questions about the origin of this mutation (independent
or common).
"Differential Gene Expression in the Lymphocytes of Malnourished
Children" by Cristina Gonzáleza, Haydeé Gonzáleza,
Leonor Rodrígueza, Leticia Cortésb, Oralia
Nájerac, Fidel Hernández-Hernándezb, Luis Floresd
and Edmundo Bonillaa.
Cell Biology International Volume 30 Issue 7 (pages 610-614). July
2006.
Summary of Article:
The article as published by the various authors above seeks to further
expand on previous research done on varying gene expression between
relatively healthy children and children suffering from marasmus type
(40%<) protein-energy malnutrition. Citing various sources they note
that PEM (protein-energy malnutrition) globally is responsible for more
than 55% of deaths among children ranging from ages 1 to 4 years.
Ultimately, the researchers sought to find whether or not prolonged
malnourishment had a statistically significant effect on the gene
expression of children and if (in the scenario that such changes did
occur) how these changes affected the individual and if they acted as
potential survival mechanisms. With the authorization of the
Ethics Committee of the Hospital Gustavo Baz, Netzahualcoyotl, Estado
de México, the researchers took blood samples from 2 groups of
children - 1 composed of well nourished children infected with a
relatively common bacteria and another group of children that suffered
from both malnourishment and the same infection. The lymphocytes of the
blood samples were processed via electrophoresis and the resultant DNA
analyzed. The results among the malnoursihed showed a particularly
great down-regulation in mexatin and zinc-finger gene expression
leading to decreased production of tumor necrosis factor (a substance
that promotes spontaneous cell death) as well as to decreased
production of a certain family of glucocorticoids that normally
surpress T Cells. The decreased production of these two regulatory
substances leads to relatively greater immune system efficiency and
lower immunosupression than one would expect for individuals suffering
from severe malnutrition, implying that the altered gene expression
serves as a survival mechanism to protect the individual from infection
while the individual is in a vulnerable state.
Why I chose this article: Gene expression at first glance seems to
serve a relatively straightforward and unbending purpose; decoding the
"pre-programmed" genetic information into living organic tissue that
later reproduces itself with the next generation. However, the fluidity
and practical purposes under which gene expression can serve also are
just as important to the survival of the individual and species as a
whole. Even under extreme duress, life finds a way to adapt within a
single generation through varied gene expression; this implies that it
may be possible (with sufficient knowledge) to manipulate the gene
expression of an individual to increase survivability temporarily (for
example in a famine an individual may exhibit survival mechanism
against ineffection) until the crisis passes - a possibility that
certainly merits further investigation.
Genetic Prediction of Future Type 2 Diabetes, Lyssenko V, Almgren P,
Anevski D, Orho-Melander M, Sjogren M, et al, PLOS Medicine, Volume 2,
November 1, 2005.
The questions posed in this article are as follows:
Do the genes PPARG and CAPN10 code for type 2 diabetes?
Can
these genes serve as a means for screening the population for T2D?
I believe that this would make a good article for us to study in class
because it is another nature vs. nurture situation. Obesity has
been around for many years, but now it has reached a peak in the United
States. I believe that this is an issue of growing concern for
Americans, and as such would make for a good topic of study.
This article displays results from possibly the largest to date study
of its kind, and reveals that certain people are genetically disposed
to developing adult onset diabetes. People expressing certain
phenotypes and having specific genotypes that are believed to be
predisposed to T2d are tested. The results are analyzed in depth
and the targeted alleles are explained. This article leaves much
left to be studied; such as why exactly these particular genes
influence development of T2D, but nonetheless studying this article
would help people understand that adult onset diabetes is a hereditary,
as well as an environmental, disease.
“Association of GABRA2 with Drug Dependence in the Collaborative Study
of the
Genetics of Alcoholism Sample” , Arpana Agrawal, Howard J. Edenberg,
Tatiana
Foroud, Laura J. Bierut, Gerald Dunne, Anthony L. Hinrichs, John I.
Nurnberger,
Raymond Crowe, Samuel Kuperman, Marc A. Schuckit, Henri Begleiter,
Bernice
Porjesz and Danielle M. Dick, _Behavior Genetics_, Vol. 36, No. 5,
pg.640-650,
September 2006.
This study examines the connection between alcohol dependency and
illicit
drug dependency possibly sharing genetic factors. The connection
between the
two have been observed but the biological inherent genes have not been
yet
associated. The method used by this study involves the use of multiplex
families affected by alcoholism, and the investigation also involved
second and
third degree relatives. Genetic predisposition for alcoholism is
weighted at
50-60% and the possibility of other dependencies such as cannabis
(marijuana),
opioids (heroin, opium, etc..), cocaine, stimulants, and sedatives are
at a
high likelihood of being in genetic association with alcoholism.
They proceed to examine this correlation more in depth by setting two
goals.
The first goal was to find out if specifically, marijuana is in any way
linked
to GABA receptor gene clusters located on chromosome 4 . And the second
goal
they set out to achieve was finding out how much influence each gene on
the
GABA gene cluster had with respect to the connection. The following
genes :
GABRA2, GABRA4, GABRB1, and GABRG1, were all used in this study and were
quantitatively compared.
Blood samples were collected from the participants and taken for DNA
analysis. With the use of SNP pronounced as “snips” and genotyping in
certain
regions that are already associated with alcoholism, they were able to
get
comparable results. SNPs, short for Single nucleotide polymorphisms are
DNA
sequence variations that occur when a single nucleotide in the genome
sequence
is changed or altered and can occur in both coding regions or exons. In
this
study both regions were taken into consideration. Since the majority or
99% of
DNA is very much the same for humans, the 1% that isn’t is very
important in the
understanding of how this variation affects diseases and may include
drug
dependence and alcoholism. SNPs are stable so using multiplex families
would
not in any way distort the data since they do not change very often.
Tests such
as the Pedigree Disequilibrium Test (PDT) was used to allow for the
consideration of larger families so that the data would be statistically
correct. To obtain the phenotypes a interview format was used and the
percentage of individuals with different combination of alcohol and
drug usage
were sorted. Of the many SNP used, 4 with GABRA2 were strongly related
to with
Alcoholism and also surprisingly were associated with drug dependence
such as
marijuana and others. The other genes, GABRA4, GABRB1, and GABRG1 did
not
present any compelling data. The interest was focused on GABRA2 which
showed
much promise continued in a succeeding study using a much more
case-controlled
method in order to get good data. The final conclusion of the study
clearly
shows that GABRA2 is very much associated with illicit drug
dependencies and
more specifically that it is narrowed down to individuals that used
drugs in a
combinations.
This article was very informative and actually has some serious
relevance in
that alcoholism and drug dependence are addictions that may be life
threatening.
The article shows the correlation between both addictions and is a very
important step in a series of many more steps to come for finding a
valuable
treatment that will help millions who have to cope with this
debilitating
disorder. Learning more about the genetics of such dependencies can
help in
utilizing this resourceful information for possibly making better
choices so
people can lead normal and healthy lives. It focuses on behavioral
genetics
showing that genes have an influence over actions and manners of
individuals.
This article adds to the debate between nature and nurture. Alcoholism
and drug
dependencies once though to be mostly influenced by environment now
shows that a
very significant genetic predisposition also exists.
Article Title: Genetic technologies, health care policy and the patent
bargain
Authors’ Names: Caulfield TA, Knoppers BM, Gold ER, Sheremeta LE,
Bridge PJ
Journal Title: Clinical Genetics
Volume: 63
Pages: 15-18
Date of Publication: September 27, 2002
This article talks about the moral controversy involved with patenting
and privatizing the human genome. The authors point out how
companies and private organizations are well within their legal realm
when they patent genes and that such privatization encourages
innovation, but they also point out the complications that can occur in
public health policy; they accomplish this by referring to a recent
issue in Canada where a company that patented a portion of the human
genome set the price for other companies to be able to use that
specific portion too high.
I think this is an extremely interesting topic that is often overlooked
by the mainstream media, policymakers, and, of course, the
apathetic. In this world where we are taught that public is bad
and private is good, it is important to realize that there are
exceptions to every rule. People don’t think of the human genome
as something to be privatized, and it would be enlightening to discuss
the pros and cons of the patent controversy.
Major histocompatibility
complex class II variation in the giant panda (Ailuropoda
melanoleuca), QU-HONG WAN, LIANG ZHU, HUA WU and SHENG-GUO
FANG, Molecular Ecology, Volume 15, pgs. 2441 – 2450, published
March 6,
2006
I thought
that this article was very interesting because its main focus is
animals
whereas most of the genetic problems that we have been dealing with
have had to
do mainly with helping humans. It deals with a genetic approach
to problems
with endangered species, mainly the panda, and not people.
It is a well known
fact that DNA can be acquired from a blood sample of an individual.
But when
the individual is a giant panda, a less invasive way to get the DNA
would be
much better. The most noninvasive way possible would be to draw
DNA from something
that the individual has left behind, such as feces. Feces is
covered with
cells from the intestinal walls of the animal and therefore is actually
a very
accurate way to get DNA, as long as it is acquired by minimizing
genotyping errors.
I haven’t heard of many animals who usually get their DNA
acquired this
way, and I think it would be a good idea for people to start trying to
find
ways that are noninvasive, such as this way, to acquire DNA. It
would be just
as accurate, but minimal pain. Another issue this article talked
about was how
lack of MHC variation makes creatures more susceptible to disease, this
is
especially important for endangered species. Currently most
scientists are
trying to increase the population of endangered species by mostly
environmental
means. I think it would be a good idea to approach this problem
with a more
scientific approach. I don’t know how, but maybe there is some medicine
that can be developed to make endangered species have a higher MHC
variation. Although,
on a different note, some of the low MHC variation in endangered
species is due
to the bottle neck effect. Because the pandas have been mating
within
themselves, they have similar genes and therefore smaller variation in
MHC. Pandas
that are part of a larger group have more MHC variation because there
is more
of a genetic variety. Forcing pandas to mate outside of their
clan and form
larger groups, and therefore more variation, would be more difficult
than
finding a scientific solution. This experiment showed that there
was small
variance in the alleles found in the pandas. There were fewer
alleles actually
found than were predicted to be found. But, even though there
wasn’t
much variation between the alleles found, in some cases there were
large
differences within the alleles. In the smaller groups there
wasn’t much
variation within the alleles and in the larger groups there was.
I think its
interesting even though there isn’t much variation in the alleles, its
possible for there to be a lot of variation within the alleles.
Article Title: “In vitro selection of halo-thermophilic RNA reveals two
families
of resistant RNA”
Authors: Jacques Vergne, Jean A.H. Cognet, Eörs Szathmáry
and Marie-Christine
Maurel
Journal: Gene, Volume 371, Issue 2, Pages 182-193
Date of Publication: April 26, 2006
Summary of Article:
This article demonstrates the idea of RNA being an integral part of the
evolution of life during the primitive years of the new world. The RNA
World
Hypothesis, as we learned in class, proposes RNA as the first biological
molecule. A test was done to see if RNA is sensitive to temperature. In
this
experiment, RNA molecules were exposed to high temperatures in high salt
concentrations to see how resistant they were to these environments,
which were
similar to the environments of the early world. Systematic Evolution of
Ligands
by Exponential enrichment (SELEX) is an in vitro evolution method in
which the
RNA molecules were tested. Through this method, the molecules were
heated
through multiple selection cycles, cloned, sequenced, and measured to
see how
resistant they were when placed in extreme conditions. The results
showed that
the resulting RNA molecules were grouped as two different families (I
and II).
These families differed in secondary structures of the RNA and
thermostability.
In family I, the secondary structures were longer and more stable than
those of
family II (to make up in lack of stability, selected sequences better
replicated
than those of family I). Also, a majority of molecules in family II
degraded
during the heating process whereas a majority in family I remained
intact.
This shows that family I RNA is stable enough to store and preserve
sequencing
information for future generations while family II may be unstable and
degrade
at high temperatures, yet the RNA molecules here carry information that
make
replication easier. Therefore, this experiment helped demonstrate how
survival
and reproduction are essential in biological evolution, through which
RNA
remained resistant to degradation from high temperature while situated
in high
salt concentrations.
The reason why I chose this article was to learn more about the RNA
World
Hypothesis since my previous biology classes had not mentioned it. I
think
this article provides us with more information on how RNA survives and
how
different factors such as heat and concentrations can affect it. On a
more
personal note, the beginnings of life on Earth have been a constant
wonder for
me, and I am sure I am not alone with this thought. If RNA provided a
pathway
for the first organisms to appear on the planet, then I think it is
worth
learning more on how such a phenomenon can occur.
“Single-Nucleotide Polymorphisms in NAGNAG Acceptors Are Highly
Predictive for Variations of Alternative Splicing”, Michael Hiller,
Klaus Huse,
Karol Szafranski, Niels Jahn, Jochen Hampe, Stefan Schreiber, Rolf
Backofen,
and Matthias Platzer, The American Journal of Human Genetics, volume
78, pages
291-302, February 2006.
The article I read, entitled “Single-Nucleotide Polymorphisms in NAGNAG
Acceptors Are Highly Predictive for Variations of Alternative Splicing”,
obviously suggests that certain sequences of nucleotides may code for
the
acceptance of a spliceosome on that binding site in the pre-mRNA, which
would
lead to a form of alternative splicing. To begin, it should be
explained that
the NAGNAG sequence represents codons in which “N denotes A, C, G, or T
in
mRNA” (The American Journal of Human Genetics). Additionally, this
article
elucidates that Single-Nucleotide Polymorphisms, or SNPs, are the “most
abundant form of genetic variation, contributing significantly to
phenotypic
individuality and disease susceptibility” (The American Journal of Human
Genetics).
Since it is known that codons located within the coding regions of mRNA
each
code for a specific amino acid within a protein, the idea that an
alteration of
amino acid sequencing may cause problems, such as disease or early
sequencing
termination, seems obvious. The extent of this effect, however, is
widely
variable. Due to the redundancy of the genetic code, as there may be 3
codons
that code for the same amino acid, certain SNPs may not create these
problems.
This article, however, argues the point that these SNPs can also
influence
splicing, by dictating the point on a pre-mRNA in which a spliceosome
binds and
begins splicing. Through a comparison of the human genome to the genome
of a
chimpanzee, several plausible and implausible SNPs were determined. Of
these,
95% of the “tandem acceptors match the consensus HAGHAG (H denotes A,
C, or T)”
(The American Journal of Human Genetics), therefore rendering the
HAGHAG as the
most plausible combinations of SNPs. Even a change of a “normal
acceptor to a
plausible NAGNAG acceptor by a single mutation is sufficient to enable
alternative splicing” (The American Journal of Human Genetics).
The article goes on to mention that “recently, splicing mutations have
been
suspected to be the most frequent cause of hereditary diseases” (The
American
Journal of Human Genetics). Therefore, the study of these SNPs seems to
be
extremely important. As the article provides data of experimentation
performed,
it shows that of these plausible SNPs, several can create alternative
splicings
that can lead to diseases such as Sjogren syndrome, Alzheimer disease,
and Down
syndrome.
The reason this article would make for an interesting discussion in
class is
that Alzheimer disease and Down syndrome are two of the most common
ailments
affecting the human populations in the world today. I know that as I
read/watch/listen to the news, stories of advances made in Alzheimer’s
research
that may ultimately lead to a cure for this devastating disease are
common.
Until now, however, I never really felt like I had the resources to
understand
exactly what these advances were, and how they were made. Since we have
recently discussed alternative splicing and it’s potential effects in
class, I
feel that this article would be a perfect supplement to the curriculum.
This article touches on the exact implications of alternate splicing in
a
relatively accessible manner, relating its initiation to the presence
of a
particular sequence of nucleotides. In studying this article, it seems
to
possible to understand how crippling diseases such as Alzheimer’s
manifest
themselves within individuals. Understanding Alzheimer’s on the genetic
level
would provide the class with a practical knowledge that could be
applied to
better understand diseases that affect so many people each year.
Therefore, I
believe this article would provide a good basis of study in our class.
Mutations in the gene encoding fibroblast growth factor receptor-3 in
achondroplasia, Francis Rousseau, Jacky Bonaventure,
Laurence Legeai-Mallet, Anna Pelet, Jean-Michel Rozet,
Pierre Maroteaux, Martine
Le Merrer & Arnold Munnich, Nature, 371,
252-254, 15 September 2002
Raises the
question of the origin of achondroplasia, characterized
by dwarfism in humans. The gene responsible for achondroplasia has
been mapped to chromosome 4pl6.3, and it seems the mutation of a single
amino acid account for all cases of achondroplasia in the
series.
An RNA gene expressed during cortical development evolved rapidly in
humans,
Katherine S. Pollard, Sofie R. Salama, Nelle Lambert and more, Nature
443,
167-172(14 September 2006),
In this research, authors attempted to identify the possible sources of
the
development of human-specific brain. They began by comparing our genome
to that
of the chimpanzee and found the “human accelerated regions”, HAR1F and
HAR1R, in
non-coding regions of RNA. In human, these RNA genes are expressed at a
very
crucial time and place in the development of the cortex, an area where
there
has been significant divergence since our last common ancestor with
chimpanzee.
The article closely relates to our topics in that it deals with RNA and
its
significant role in affecting the development of human-specific
structures. I
found this article very intriguing because not only does it uncover the
truth
of the development of our uniquely designed brain, but it also suggests
the
potential methods for analyzing the key events of the human evolution.
It could
help our class to understand the concept of RNA expression by providing
real-life examples and connecting the dots in the big picture.
Article Name: Distinct Clinical Phenotypes Associated with a Mutation
in the
Mitochondrial Translation Elongation Factor EFTs
Authors: Jan A. M. Smeitink,* Orly Elpeleg,* Hana Antonicka, Heleen
Diepstra,
Ann Saada, Paulien Smits, Florin Sasarman, Gert Vriend, Jasmine
Jacob-Hirsch,
Avraham Shaag, Gideon Rechavi, Brigitte Welling, Jürgen Horst,
Richard J.
Rodenburg, Bert van den Heuvel, and Eric A. Shoubridge
Journal: American Journal of Human Genetics, September 15th 2006
Description: I chose this article because it was about phenotypes that
can
mutate in mitochondrial translation elongation factor (EFT). The
genetic basis
for a mitochondrial protein-synthesis defect associated with a combined
oxidative phosphorylation enzyme deficiency was investigated in two
patients.
The data proves that mutant EFTs were the cause of disease in both
patients.
The overall idea that a mutation causes a disease or disorder parallels
what we
have leaned in class. The article has a lot of technical terms that are
very
hard to understand, but the overall theme is very interesting.
Title: Association of a functional serotonin transporter gene
polymorphism with binge eating disorder
Authors:
Palmiero Monteleone, Alfonso Tortorella, Eloisa Castaldo, Mario Maj
Journal:
American Journal of Medical Genetics Part B: Neuropsychiatric Genetics
Volume: 141B
Issue 1
Pages: 7-9
<>Date of Publication: Oct 25, 2005
<>
<>
<>The reason I chose this article and why I think it will be of
particular interest to the class is simply because, after all, we are
college students and we know all about eating, particularly unhealthy.
Once I saw this article, I got to thinking...could my excessive eating
habits be something that is genetic? I mean come on, we all get hungry
but for some reason it feels like nothing can ever satisfy my hunger as
I am always indulging myself in mass quantities of food
every couple hours. This article examines whether the polymorphism
of the promoter of the 5HTT gene (5HT is brain serotonin), consisting
of two variants a long and short, are associated with binge eating. No
other case has been setup that has tried to show the correlation
between 5HTTLPR and binge eating disorder. Therefore, case studies
were setup that showed differences in 5HTTLPR genotype and allele
frequencies between patients with the disorder and normal healthy
weight subjects as well as possible relationships between 5HTTLPR and
phenotypic variables.
<>
Comprehensive splice-site analysis using comparative genomics,
Nihar Sheth, Xavier Roca, Michelle L. Hastings, Ted Roeder, Adrian
R.Krainer and
Ravi Sachidanandam, Oxford Journals: Life Sciences; Nucleic Acids
Research, Vol.
34 Number 14, pgs. 3955-3967,August 12,2006
The main question that is posed in this journal is the identification of
the naturally-occurring splice sites that help to give insights into
pre-mRNA
splicing. The concept of alternative splicing is not agreeable to an
analysis based solely on splice sites. In order to identify common and
distinguishing features in each splice-site type, the researchers have
collected and analyzed a comprehensive set of naturally-occurring
splice sites
from the genomes of five model organisms, through this they will reach
a greater
understanding of complete splice-site analysis using comparative
genomics.
I think that this article will be an interesting one to study in our
class because it builds on a topic which we have covered (introns,
exons, and
splicing) and makes for a real experimental understanding of the
concept and
how the process works. With a new understanding on topics we have never
heard
of before.
The group of researchers listed above have collected over half a
million splice
sites from five species: which include:Homosapiens, Musmusculus,
Drosophila
melanogaster,Caenorhabditis elegans and Arabidopsis thaliana—and
classified
them into these four subtypes: "U2-type GT–AG and GC–AG and U12-type
GT–AG and
AT–AC." They have also
found new examples of uncommon splice-site categories, such as U12-type
introns
without canonical borders, and U2-dependent AT–AC introns. For the
U12-type
introns, they found several features conserved across species, as well
as a
clustering of these introns on genes. Using the information content of
the
splice-site motifs, and the phylogenetic distance between them, they
identified
through there research: "(1) a higher degree of conservation in the
exonic
portion of the
U2-type splice sites in more complex organisms; (2) conservation of
exonic
nucleotides for U12-type splice sites; (3) divergent evolution of
C.elegans
3' splice sites Their study proves that the identification of broad
patterns in
naturally-occurring splice sites, through the analysis of genomic
datasets,
provides mechanistic and evolutionary insights into pre-mRNA splicing."
Historically, splice sites are ranked, based on compilations of splice
sites.
However, none of these ranking schemes accurately identify the bona
fide splice
sites. In addition, alternative splicing, involving the choice of
competing
splice sites, is not amenable to an analysis based solely on splice
sites. In
order to identify common and distinguishing features in each
splice-site type,
the researchers have collected and analyzed a comprehensive set of
naturally-occurring splice sites from the genomes of five model
organisms: Homo
sapiens, Mus musculus, D.melanogaster, Caenorhabditis elegans and
Arabidopsis
thaliana. They have revisited relevant themes in splicing, such as the
frequencies of U12-type and other rare introns, and the variations in
the 5'
and 3'ss motifs among the five organisms.
The final results go into great depth of how the introns were
classified into
various splice-site subtypes. And furthur how they were able to
retrieve splice
sites by type. They came to the conclusion that this tool allows users
to
retrieve splice site flanking sequences by specifying one or more
splice-site
subtypes, cut-off 5'ss or 3'ss scores, and species. By using this tool
one
will be able to locate potential protein-binding sites by searching for
sequences that match the patterns in the form of regular expressions.
Title of Article: An mRNA structure in bacteria that controls gene
expression by binding lysine
Authors: Narasimhan Sudarsan, J. Kenneth Wickiser, Shingo Nakamura,
Margaret S. Ebert, and Ronald R. Breaker
Journal Title: Genes and Development
Volume: 17
Page Numbers: pp 2688 - 2697
Date of Publication: Nov 2003
Description of Question Posed:
The description of the question posed here relates to the direct
sensing of metabolites by messenger RNAs is a fundamental form of
genetic control and that riboswitches represent a new class of
antimicrobial drug targets.
Reason Why Article Should Be Discussed:
The article should be discussed due to the fact that most known genetic
factors
that respond to such environmental changes are proteins, but, in this
experiment, it is shown that RNA molecules can also recognize small
organic compounds and harness allosteric changes to control the
expression of adjacent genes. These metabolite-binding RNA domains,
termed riboswitches, typically are embedded within the 5' untranslated
regions (UTRs) of mRNAs, and control the expression of proteins
involved in the biosynthesis or import of the target compound. (e.g.,
see Mironov et al. 2002; Nahvi et al. 2002; Winkler et al.
2002a,b). By binding Lysine, the mRNA structure in the bacteria
controls the gene expresson. It is termed “lysC”, and the lysC gene
basically encodes aspartokinase II, which catalyzes the first step in
the metabolic pathway that converts L-aspartic acid into L-lysine
(Belitsky 2002). This
article is vital and should be discussed because the data from the
study strongly support that a lysine-responsive riboswitch might serve
as the genetic control element for this gene, and that riboswitches
represent a new class of antimicrobial drug targets.
Genome Survey for Loci That Influence Successful Aging: Results at 10-cM
Resolution, George S. Zubenko , M.D., Ph.D., Hugh B. Hughes III, M.S.,
Wendy N.
Zubenko , Ed.D., A.P.R.N., Brion S. Maher , Ph.D, American Journal of
Geriatric
Psychiatry, online, August 11, 2006.
This article is asking about the genetic differences between the very
old and
the young. It asks—is there some genetic difference in the people that
grow
very old that allows them to do so? Or, is there something in the genes
of
young people that predetermines that they will never live into old age?
George
Zubenko, a professor at the University of Pittsburgh School of Medicine
compared
the DNA of 100 men and women who had reached the age of 90 while still
maintaining mental cognition with the DNA of 100 young adults with
similar
proportions of sex and race.
The study found several interesting differences between the genes of
the young
and the old. The older people were much more likely to have the APOE E2
allele
and much less likely to have the APOE E4 allele than the group of young
adults.
Zebenko also discovered nine new genetic regions specific to men or
women that
are believed to be associated with successful aging. Most of these
regions
overlap with regions that are linked to cardiovascular and other
disorders, and
the presence of these “successful aging genes” is believed to inhibit
those
disorders. The article also touches on the nature vs. nurture debate on
aging.
The study found that those who did not smoke or drink were much more
likely to
live into old age.
This article would be interesting for class because everyone wants to
live into
old age. This was just published, and it has the most current ideas
about what
it is that allows some people to live so much longer than others.
Theoretically, we could all have our DNA examined for the traits
described in
the article and see if we have the genetic predisposition to live into
our
nineties—which sounds pretty interesting/scary to me.
THE EVOLUTION OF GENETIC ARCHITECTURE. I. DIVERSIFICATION OF GENETIC
BACKGROUNDS
BY GENETIC DRIFT, Reinaldo A. de BritoA, 1, L. Susan PletscherA, James
M.
Cheverud, Evolution Vol. 59, Issue 11 pp. 2333–2342 (November 2005)
In searching for the relationship between the evolution of genetic
architecture
and genetic drift, researchers tested the breeding value of four
standard
inbred mouse strains mated across a set of recombinant lines generated
from the
intercross of the two different inbred mouse strains. The result showed
that
there is strongly significant interaction for all traits which means
the traits
were differentiated by genetic drift during the production. Also, it
suggested
that common patterns of selection in these differentiated populations
could
result in the fixation of different alleles.
I honestly could not fully understand the result of the experiment
since I
barely have any knowledge regarding the complicated multi-cross between
sets of
different traits. Some analysis, however, was familiar since it
involved the
basic concepts of the genetics, such as the founder effect and the
genetic
drift. I believe studying this article and topic could lead us to
in-depth
analysis of the evolution of genetic architecture and its impact on
genetic
diverisifcation.
“Re-analysis of Collaborative Study on the Genetics of Alcoholism
pedigrees
suggests the presence of loci influencing novelty-seeking near D12S391
and
D17S1299.” David Curtis. Psychiatric Genetics, Vol. 14 Issue 3,
p151-155,
Sep2004.
Are human personality traits heritable? Previous analysis of 758
sibling pairs
from families of alcoholic found evidence for linkage harm avoidance to
markers
on 8p21-23, and this study was supported by other linkage study of 384
sibling
pairs. The tri-dimensional personality questionnaire about
novelty-seeking,
harm-avoidance, and reward-dependence was used to study influence of
genetic
variants to these traits. There have been two previous linkage studies
of
these personality traits. The first one was carrying out genome scan of
758
sibling pairs from 177 alcoholic nuclear families. This experiment
showed that
linkage of harm avoidance is marked on 8p21-23 with additional markers
on 18p,
20p and 21q. The second experiment provided the evidence of markers on
8p21,
1q21-24, and 22q12-13.
The dataset of 105 pedigrees containing 1214 subjects is collected for
Collaborative Study on the Genetics of Alcoholism. The pedigrees are
selected
for having three or more members affected with alcohol dependence and
provided
with tri-dimensional personality questionnaire. Linkage analysis of the
three
personality traits was carried by lod score analysis of quantitative
traits
implented in the QMFLINK program. For each test, likelihoods are
calculated
for a range of transmission models. Also for each pedigree likelihoods
were
calculated under condition of linkage and non-linkage.
Through the results, it was clear that trait of novelty-seeking was more
heritable traits than harm-avoidance and reward-dependence. And
Reward-dependence produced result of least related linkage traits.
Linkage between traits and genetic variance is controversial. Many
positive
and negative experiments were carried out, but lack of consistency in
the
results gives difficulty in drawing conclusion.
This research will make class interesting since people usually believe
that
main component of building personality is environment. This research
investigates how one gene can builds up person’s certain
characteristics. This
study raises question of nature vs. nurture. Are characteristics and
personality genetically heritable, or are nature and nurture
interrelated to
build up person’s characteristics? Genetic class will have a lot of fun
by
investigating these questions.
Mother knows best: Epigenetic inheritance, maternal effects, and the
evolution
of human intelligence
Developmental Review
Volume 26, Issue 2, June 2006, Pages 213-242
The article written by David F. Bjorklund focuses on a new part of
genetics
that we have yet to discuss in class. It is called epigenetic
inheritance.
Epigenetic inheritance deals with changes in gene functions without a
change in
the DNA sequence. This field in genetics is unique because most of what
we
research is done by comparing one generation’s genes to its ancestors,
in which
physical differences can be traced. But what about behavior,
personality, or
intelligence? We can obviously see the physical differences but mental
differences become much harder to trace genetically. The article
briefly brings
up the idea of postnatal behavior using rats in their experiment. The
experiment
used rats that were handled and nonhandled resulting in an offspring of
different natures. The handled rats were more active and curious to
explore
environments than the nonhandled rats. This answers the question to
whether you
can link behavior genetically through generations. It was found that
the gene
linked to the activeness in the rats was found in it’s ancestors, the
C57BL/BALD strain.
Another experiment in the same article linked licking and grooming and
arched-backed nursing (LG-ABN) to behavior in their offspring. Children
from
families with high levels of LG-ABN are less stressful than offspring
with
lower levels of LG-ABN. When the children were switched to foster
parents,
their stress resembled that of their foster parents than maternal. After
inheriting the behavior from the foster parents, it was found that the
same
behavior was passed down at least 2 more generations. Conclusively,
individuals
differ in behavior because of variations in care. This idea belongs
with the
nature vs nurture idea about sexuality and how one is brought up in
society,
providing more positive evidence to support the reasoning.
Age and Apolipoprotein E*4 Allele Effects on Cerebrospinal Fluid
-Amyloid 42 in
Adults With Normal Cognition
Elaine R. Peskind, MD; Ge Li, PhD, MD; Jane Shofer, MS; Joseph F.
Quinn, MD;
Jeffrey A. Kaye, MD; Chris M. Clark, MD; Martin R. Farlow, MD; Charles
DeCarli,
MD; Murray A. Raskind, MD; Gerard D. Schellenberg, PhD; Virginia M.-Y.
Lee, PhD;
Douglas R. Galasko, MD
Archives of Neurology. July 2006;Volume 63:936-939.
The objective of this research article is to determine the effects of
normal
aging and the presence of the APOE*4 allele on A beta 42 protein
concentration
in spinal fluid of adults. Alzheimer's-related plaques composed of A
beta 42
proteins begin to form on the brain years before any symptoms of the
disease
are shown. Due to the clumping of the A beta 42 protein into plaques on
the
brain, there will be less of this protein in spinal fluid. Therefore, a
decreased level of A beta 42 in the spinal fluid can indicate the
development
of Alzheimer's. This study found that older people with the APOE*4
allele are
more likely to have lower levels of A beta 42, than those without the
allele.
People with the APOE*4 allele showed a slight decline in the A beta 42
concentrations at a much earlier age, followed by a dramatic delcine
from 50-60
years old. Researchers report that people with the APOE*4 develop
'clinical
dementia' 10-15 years sooner than those without it.
“Type 2 diabetes mellitus: from genes to disease”, Maciej T. Malecki
and Tomasz
Klupa, Pharmacological Reports, Volume 57, Pages 20-32, 24 August 2005
The chosen article addresses the current status of Type II Diabetes
Mellitus
(T2DM) research in terms of genetics. Malecki and Klupa report on the
current
findings that relate monogenic mutations on the DNA to strong cases of
the
disease. However, there are many exceptions to the findings; in fact,
90% of
cases of diabetes are found to be caused by changes at multiple loci.
This is
further seen by the fact that cases of T2DM show that it can cause two
different effects: insufficient insulin secretion in the body and/or a
decrease
in the ability of cells to take up the insulin. The genetic nature of
the
disease is supported by the fact that there is a higher prevalence of
diabetes
in monozygotic twins versus dizygotic twins and that there is a higher
frequency of diabetes in certain families. The big question that is
partly
discussed, but never concluded upon is the argument over nature versus
nurture.
Despite the findings of science, there is a variety of exceptions that
reinforce
the environment’s role in determining the phenotype of the disease.
Differences
in the prevalence of the disease based on ethnicity and geographic
regions are
cited by Malecki and Klupa. At no point can they determine the specific
affects
that nature or nurture plays in the determination of the gene.
“Environmental factors may be responsible for the initiation of
â-cell damage or
other metabolic abnormalities, while genes may regulate the rate of
progression
to overt diabetes. On the other hand, in some cases genetic factors may
be
necessary for environmental factors even to start processes leading to
the
development of the disease” [1].
The authors are unable to explain the polygenic appearance of certain
cases and
instead speak about the clearer monogenic form. In monogenic diabetes
cases,
there has shown to be a high chance that the disease will occur in the
individual. Such affected individuals are largely affected by their
“nature”
over the environment’s influence, though they explain that the
environment
still plays its role. These individuals have severe defects in their
organs
that produce insulin and thus are the worst cases of type II diabetes.
Mutations affecting transcription and translation factors have been
found. In
the case of those that affect transcription factors, nature plays a big
role in
determining the appearance of the disease; most cases are severe and
early
onset. In contrast, translation factors are highly affected by the
environment.
Even in cases with the same monogenic mutation, the environment can be
the
deciding factor in determining the appearance of the disease.
Another question that scientists continue to ask is about the pathway
for
insulin within the body’s cells. There exist insulin resistant cells
that are
also the cause of monogenic type II diabetes, but because insulin’s
path and
its action on the cellular level is complex, it is relatively unknown.
Complex Type II diabetes, a more common form of the disease, has an
unknown
interaction between genetics and environment. In cases with polygenic
inheritance of diabetes, there exist many loci that are said to be the
causes
of the disease. The genes that cause the disease vary greatly and there
has
been little success in relating the disease to any specific, universal
loci
mutation.
“The final number and the relative contributions of these genes are
uncertain…they may belong to the same or to different casual pathways.
Some
genes may contribute substantially to the development of diabetes in one
population with no or limited effect in another ethnic group.” [2].
Even when signs of the disease exist genetically, the disease doesn’t
automatically appear. The goal of determining the loci that cause the
disease
is extremely difficult because of environmental factors; there are
cases where
there doesn’t seem to be any genetic link. In contrast, many
individuals have
the genes that seem to cause the disease, but never express them due to
differences in environment.
This journal article is useful because diabetes is a disease that is
highly
prevalent in most industrialized countries around the world. A more
disturbing
fact is that the percentage of cases is increasing, especially in
younger
people. Such questions bring about a more realistic issue to the topic
of
genetics as many of us know someone affected by the disease. Diabetes
also
causes a decrease in life expectancy of those that are affected by it
and thus
it is a major health problem in our society.
Genomics of the future: Identification of quantitative trait loci in
the mouse
Lorraine Flaherty1, Bruce Herron and Derek Symula
Genome Research
Volume 15(12)
pages 1741-5
2005 Dec
The article is about studying mice genes in order to help find
diseases, find the particular genes that cause them, and also their
positions in the chromosomes. New technology in the field helps
us do this research quicker and with more precision. The article
also goes over the new methods that can be used to help us solve these
complex problems. The article is interesting because it focuses
on the future of gene research and what students might encounter in the
field in a few years.
"Long-term gene expression changes in the cortex following cortical
ischemia
revealed by transcriptional profiling" by Carola Krüger, Durmus
Cira, Clemens
Sommer, Achim Fischer, Wolf-Rüdiger Schäbitz,and Armin
Schneider
Source: "Experimental Neurology" Volume 200, Issue 1 , July 2006, Pages
135-152
The article is concerned with the molecular changes that are involved
in a
post-cortical ischemia rat model that simulates stroke. The gene
expression
patterns contribute to the neural reorganization after injury, but it
has not
been fully explored how most of these regulatory genes actually affect
injured
neurons. It is the purpose of this paper to more clearly define the
role of
many genes shown to change following a photothrombotic ischemic injury
induced
in the rat parietal cortex.
The issue of neuronal restructuring is a hot topic right now in
Neuroscience
and the effects of regulatory genes in this process are beginning to be
understood. Regulatory genes are very important in sustaining life and
often
the field of Molecular Biology seems to focus on genes as what forms an
organism and not as much on what sustains them also. This paper brings
to light
the future of medicine in the potential for pharmaceutical gene therapy
replacing older methods like surgery in some cases or allowing medical
assistance to the injured or impaired where there was no hope before.
Neuroscience is a field that a lot of students are not exposed to very
early
on but many find it interesting because of the complexity and because
of how
much we know about the brain and how much we still do not know.
New gene construction strategy in T-DNA vector to enhance expression
level of
sweet potato sporamin and insect resistance in transgenic Brassica
oleracea,
Huai-Ju Chen, Shu-Jen Wang, Chien-Cheng Chen and Kai-Wun Yeh, Plant
Science,
Volume 171, Issue 3 pg 367-374, Sept 2006
This article asks the question could a specific plant gene, sporamin, be
activated in sweet potatoes to make it more pest resistant? In
experimentation,
the authors tried to see if adding a wound-responsive promoter or a DNA
attachment would encourage higher levels of sporamin. Through their
results,
they found the subjects that contained both the attachment and the
promoter
would display greater amounts of sporamin and therefore greater pest
resistance. They also found that in subsequent generations, the
promoter and
attachment were stable and inheritable.
This article would be interesting because it talks of genetically
modified
food and the stability that is being found in the modifications that
can lead
to future benefits.
“Unraveling
adaptive evolution: how a single point mutation affects the protein
coregulation network”, Christopher
G Knight, Nicole Zitzmann, Sripadi Prabhakar, Robin Antrobus, Raymond
Dwek,
Holger Hebestreit & Paul B Rainey, Nature Genetics,
Volume
38 No 9,1015-1022, Published online: 20 August 2006
After reading this article I feel
that the article leads the reader to think about some very significant
questions that are either directly mentioned in the context of the
article or
brought about by the assumptions that the researchers make. The
most
important questions that I found myself asking from reading this
article were the
following: “Is evolution still occurring in today’s species?”,
:Can we see adaptive evolution in a controlled environment?”, ”Can
we study evolution on the DNA level?”, ”How significant is a single
base pair mutation on the entire organism?”, and “How does adaptive
evolution affect the ecosystem?”.
The article shows evidence to
studying the evolution in bacteria in a laboratory environment and from
that occurrence
I found myself asking two questions. The first question I asked
was, “Is
evolution still occurring in today’s species?”. I believe
that species have evolved over time and after this question I was
asking myself
whether or not evolution was continuing to occur in today’s species.
It
makes sense that species are constantly evolving and adapting if one
adopts the
mentality that evolution is in fact a legitimate explanation for our
origins,
but this article assumes that not only is evolution still occurring but
it is
also observable and recordable. This assumption leads me to
question
whether or not adaptive evolution can be seen in a controlled
environment.
Every biology student is taught about Darwin’s
finches with different shaped beaks, but it is still a theory to why
and how
the beaks came to be. In this controlled experiment the
researchers go to
show that they can record this bacteria adapting to its new niche.
After I got deeper into the
article it began to discuss the adaptive evolution of a certain
bacteria and
how they could see a difference between the genes of the old bacteria
and the
new, evolved bacteria. This forced me to ask, ”Can we study
evolution on the DNA level”. This article seemed very confident
that they could track the evolution from the old bacteria that stayed
in the
liquid to the new bacteria that made formed a boundary between the air
and
liquid in the DNA. They found one mutation in one base pair and
accredited
the evolution to that one mutation. The researchers believed that
it was
the forces of pleiotropy that made this one base pair affect so much on
the
entire organism and made me wonder, “How significant is a single base
pair mutation on the entire organism”. In this case the
researchers
found this one base pair to be very important to the entire organism,
but how
significant is each base pair. Some base pairs probably control
very
important things such as this one must have, but others might not
control
things so important.
The last question I found myself
asking was since these researchers found that this bacteria filled a
new niche
in the ecosystem that they made as a control environment, “How does
adaptive evolution affect the ecosystem”. This article leads me
to
believe that the mutation occurred first and that the new niche was
filled second
like the mutation caused the shift of niche. I find it peculiar
that the
mutation forces the change rather than so much I have learned before,
which assumes
that a change in the environment forces a shift in the genes over a
long period
of time. This article goes against what I had learned and stated
that the
mutation caused the shift and could be seen within the duration of
their experiment.
Overall, I feel that this article
has a lot of relevance to our class because it assumes a lot of things
that
people as a whole are not completely comfortable with. I also
feel that
this article views evolution at both a genetic level and an ecosystem
level,
which goes to show the differences between the two ways of studying
evolution,
but also tries to connect the two to make the theory of evolution more
solid.
Molecular analysis of flies selected for aggressive behavior, Herman A.
Derick and Ralph J Greenspan, Nature Genetics, pages 1023-1031,
September 2006
The authors of this article wanted to see whether flies selected for
aggression showed different expressions of genes. To find out they ran a
simple experiment where they started with a normal population of flies
from which they selected flies to make offspring. By selecting flies
that showed aggressive territorial behavior, such as fighting with and
tossing other flies, they created two populations of aggressive flies
over 20 generations. By also randomly selecting flies from the original
group they created two populations of neutral flies. After each
subsequent generation the aggressively selected flies’ offspring became
more and more aggressive. After over 20 generations, the two aggressive
populations fought more often, fought longer, and fought more intensely
than the two neutral populations, even though both types were equally
active in other activities. Surprisingly the aggressive flies mated less
than the neutral flies when they were in direct competition with one
another. The authors believed that this is due to the fact that in the
experiment mating was not linked territory. This find shows that
aggression only has evolutionary significance when taken in a
territorial context.
When the experimenters analyzed the RNA in the brains of the flies they
found there were eighty genes that were significantly expressed
differently between the aggressive and neutral populations. The
aggressive flies had higher expression of genes for muscle contraction,
CA2+ signaling, energy metabolism, and cuticle formation. These changes
in the genome the authors suggest allow the aggressive flies to fight
harder and longer than neutral flies.
After analyzing the differential expression of genes between the
aggressive and neutral flies the experimenters used some of these genes
in mutant flies to see if they produced an observable phenotypic effect
on aggression levels. They found that the gene that encodes for
cytochrome P450 produced a positive measurable effect on aggression. The
experimenters believe that this protein could be involved in pheromone
recognition of other male flies, which could lead to greater aggression.
This article is interesting because it showcases the two way interaction
of genes and the environment. After only a short period of time the
experimenters were able to radically alter the genome of the flies by
only selecting for one phenotypic trait. Likewise, the changes in gene
expression effected the flies’ interaction with the environment in
aggression and different tasks such as sexual competition.
The Use of Racial, Ethnic, and Ancestral Categories in Human Genetics
Research;
Kate Berg, Vence Bonham, Joy Boyer; American Journal of Human Genetics
77.4
(Oct 2005): p519(14)
The concept of genetic differences between races and ethnicities give
way to
conflicting ethical views. Some people believe that the whole concept of
researching genetic differences between races and ethnicities is useless
because of the major health differences that are caused by economical
differences within their society. There is also the questioning of
stereotyping
these races and ethnicities by way of amplifying and exaggerating
genetic
findings in order to give berth to genetic superiority or inferiority.
On the
other side of the argument, races and ethnicities are exposed to
different
environments all over the world. Researching their genetic makeup in
these
different environments is a huge point for this side of deliberators
when
wanting to find origins of diseases. I believe this is a very important
issue
to be deliberated. This is a very ethical and sensitive issue, and one
of which
that should be discussed within the classroom. It deals with the
diversity of
humans genetically and their respective environments. Researchers try
to figure
out if a connection between the two exists and what type of effects the
environment has upon the genetic makeup. Another question posed in the
article
asked if races were classifying people unfairly and inaccurately. The
researchers also deal with discussing how researchers can modify their
methods
in order to cool down the criticisms of this topic, such as broadening
their
classifications. A proposal that arose from these discussions was
ancestral
classifications. The author brings up another issue for Americans in
that there
are many studies which propose the cause of major health issues between
them.
They do not believe that these health problems are genetic as much as
they
believe prejudice, poverty, and health care accessibility among other
things.
When exploring the possibilities of disease rise, some researchers
posed that
they might originate from combinations of rare cases of that disease
through
different allele frequencies. This would be a great discussion in class
because
of RNA editing and alternate splicing with the introns/exons.
DNA mimicry by proteins and the control of enzymatic activity on DNA
Dryden DTF
TRENDS IN BIOTECHNOLOGY 24 (8): 378-382 AUG 2006
DNA requires specific enzymes to bind with proteins to produce a useful
reaction. However there are competitor proteins that compete for the
spot with
different proteins. However there is another interaction with the
enzymes and
the control protein that blocks the interaction with the DNA and binding
enzyme. This type of interaction can occur in two ways: either indirect
or
direct. One way to block the control protein to the binding site is to
“mimic”
the natural substrate. The mimic has to have the same shape and
electrostatics
that the enzyme would normally recognize. This type of mimicry is known
to
occur upon DNA, including transcription, repair, and restriction. A
profession
that has taken off with mimicry is the pharmaceutical industry. Mimicry
in this
industry has created many new drugs for the public to use to their
advantage.
DNA mimicry by proteins has advanced so much that nature isn’t stopping
this
phenomenon. “The protein structures used by DNA mimics cover all know
secondary
structure types-alpha helices, beta strands and peptide loops”. DNA
mimicry has
come so far along that it can be performed either naturally or in the
lab by
scientist. Mimicry can be used in the following of ways: it might be
possible
to use DNA mimics instead of actual DNA molecules in the preparation of
co-crystals, labeling experiments for detection of target DNA-binding
proteins
and their isolation using affinity methods, and finally mimics might be
able to
target not only bacterial restriction systems but also other systems
such as
replication, repair and drug resistance. The mimicry of a protein to
compete
with actual natural protein to mimic its shape, size, and
electrostatics to
beat it out of its spot is pretty amazing and scientists are only
finding new
ways to mimic these substrates. In the future it is said, that they
will have
proteins to mimic every site of binding for a DNA structure.