Your Weekly KromoNews: July
10, 2005
This Week in Genetics
Asthma may be related to the variability in a prostanoid receptor
Currently at
least 10 genes have been implicated in the development of asthma. The latest
one, the prostanoid DP receptor, was identified by the researchers from Emory
University. If the results of the study that they conducted, are reproducible,
the genetic screening for variability in prostanoid DP receptor may help to identify
those individuals who are at risk for asthma.
Read Full Story
Genes may determine cholesterol levels
A study of 28 pairs of identical twins found that the blood levels of
cholesterol in response to fatty food intake were largely determined by
genetics. Depending on the genetic make-up some twin pairs were able to eat
cholesterol rich foods without significant change in blood cholesterol levels,
and some responded with a noticeable rise in LDL (bad cholesterol).
Read Full Story
Genetics of addiction
While addiction is recognized as a product of genetics and environment, the
exact role of genetics remains yet to be determined. Scientists from National
Institute on Alcohol Abuse and Alcoholism discuss the genetic factors that
predispose an individual to addictions.
Read Full Story
Topic of the Week:
Genetics of Blood Type
This week we cover the genetics of Blood Type, not considering the Rhesus factor.
This is a relatively easier and well understood topic, still you may be suprised
to find complexities and subtopics that are not well explained yet.
There are four known types of
blood: A, B, AB and O. These phenotypes are produced as a result of genetic
combination of three alleles: A, B, and O. Alleles A and B are co-dominant and
allele O is recessive.
Alleles A and B code for specific markers on the surface of
the red blood cells, called antigens. Allele O by default means absence of
antigen.
A person with type A blood has antibodies to antigen B
but not to antigen A.
A person with type B blood has antibodies to
antigen A, and the person with type AB blood will not have either of the
antibodies. A person with type O has both anti-A and anti-B antibodies
but no A or B antigens.
ABO types are inherited through the genes, which are located on chromosome 9. A
child receives one of the three alleles (ABO) from each parent. The
possibilities for blood type in the child depending on the
blood types of the parents
can easily be calculated using rules of dominance, and can be found
here.
The inheritance is final and does
not change under the environmental influences.
The prevalence rates of different blood types in the population are
O: 46%, A: 40%, B: 10% and AB: 4%.
Advanced Topics:
1. There exist theories that blood
types evolved along with human evolution. They are said to progress from only
type O for early humans to type A and B as humans developed agriculture and
husbandry; and to type AB at last.
2. A small number of people have two different blood types.
Scientists think that this can occur as a result of sharing the same blood
supply with a non-identical twin, who died during the embryonic period; as a
result of blood transfusion, or mixing of fetal and maternal blood during
delivery. A recent discovery of various subtypes among each blood type tells
us that there is still much more to learn about blood type inheritance and
expression.
3. Finally, there is a concept of the "Bombay genotype", that occurs
when a child with O blood type is born to parents, one of whom
has AB blood type (and therefore does not have the O allele).
This seemingly impossible phenotype manifestation is referred to as Bombay phenotype.
Read full article.
GeneMarket
This week we focus on the kids (and gifts for kids).
Check out
"The Cartoon Guide to Genetics"
by Larry Gonick, Mark Wheelis.
It has about 224 pages, costs only about 11 USD, and available with free shipping.
Must for any high school teacher or genetics enthusiasts.
ISBN: 0062730991, available from
Amazon.
GeneMatics Update
GeneMatics 2.2.6 allows you to create setups with arbitrary population size and an arbitrary number of generations. Download your free copy here!
Upcoming Events
This week we are pleased to announce:
Celldance Festival 2005 -
First Annual Cell Biology Film Contest by American Soceity for Cell Biology.
(ASCB website)
First prize $500 (cash!) Entry deadline September 30, 2005!
Additional runners up will receive smaller cash prizes. A "Celldance Festival 2005" winners reel will be posted for free, open-access downloading at ascb.org and promoted for free use in education, media outreach and other non-commercial use.
Entries can be submitted for publication in the ASCB journal, Cell Biology Education.
Entries can be descriptive or experimental, newly-created video or classic 8/16-mm films transferred to video, animations, cartoons, or dynamic sequences from electron microscopy.
Entry deadline is September 30, 2005. Winners will be notified in advance and prizes awarded this December at the ASCB’s 2005 Annual Meeting in San Francisco.
Contact: Website
Trivia
(Puzzle Answers)
To last week's puzzle, we received correct
replies by Preeti Sareen and Issa Hussein. Congratulations to both!
The correct answer is: Jim has blood type AB.
Janet and Jennyfer are O, and Jack and Jill are heterozygous A and B (or B and A).
Also John and Justin are heterozygous A and B (or B and A).
[Unfortunately, any emails that were sent to the answers email box late last Sunday may have
been lost due to an email glitch, that was corrected early Monday morning. We apologize
for any inconvenience.]
This edition of KromoNews brought to you by: GeneMatics. Download your free copy today!
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