I doubt it, it's so little understood yet that your information could still be considered up to date. We look at the frequency of the allele in the population and note that there is an anomaly in Europe, the only explanations are increased mutation rates or a positive selection pressure (or lack of a negative one).

We can say for certain that something in Europe has led to increased fitness (and therefore fertility one could argue, depending on definition), the cause is still somewhat of a mystery.

We can say for certain that something in Europe has led to increased fitness (and therefore fertility one could argue, depending on definition), the cause is still somewhat of a mystery.

Oooh some interesting reading there, but thats not quite what I meant. I was referring particularly to the high incidence of carriers of the gene that codes for cystic fibrosis. There must be some heterozygote advantage to enable it to spread so we are looking for what the advantage conferred might be.

Cystic Fibrosis
Balanced polymorphism may explain why cystic fibrosis is so common- the anatomical defect that underlies CF protects against diarrheal illnesses, such as cholera.

Cholera epidemics have left their mark on human populations, causing widespread death in just days. In the summer of 1831, an epidemic killed 10 percent of the population of St. Louis, and in 1991, an epidemic swept Peru. Cholera bacteria causes diarrhea, which rapidly dehydrates the body and can lead to shock and kidney and heart failure. The bacterium produces a toxin that opens chloride channels in the small intestine. As salt (NaCl) leaves the cells, water follows, in a natural chemical tendency to dilute the salt. Water rushing out of intestinal cells leaves the body as diarrhea.

In 1989, when geneticists identified the CF gene and described its protein product as a regulator of a chloride channel in certain secretory cells, a possible explanation for the prevalence of the inherited disorder emerged. Cholera opens chloride channels, letting chloride and water leave cells. The CFTR protein does just the opposite, closing chloride channels and trapping salt and water in cells, which dries out mucus and other secretions. A person with CF cannot contract cholera, because the toxin cannot open the chloride channels in the small intestine.

Carriers of CF enjoy the mixed blessing of a balanced polymorphism. They do not have enough abnormal chloride channels to cause the labored breathing and clogged pancreas of cystic fibrosis, but they do have enough of a defect to prevent the cholera from taking hold. During the devastating cholera epidemics that have peppered history, individuals carrying mutant CF alleles had a selective advantage, and they disproportionately transmitted those alleles to future generations. However, because CF arose in Western Europe and cholera in Africa, perhaps an initial increase in CF herterozygosity was a response to a different diarrheal infection.

However, I'm now intrigued about the kid with the instance of double anti-myostatin genes. Do you have a reference I can go and take a peak at, I'm envisaging some kind of Arnie Kid.

Actually, is this the kid who was all over the news as the worlds strongest child?

prolescum wrote on Dec 27^th, 2009 at 6:16am:


What, like the PMing system

prolescum wrote on Dec 27^th, 2009 at 7:26am:


Really????

Censorship much?

oh_noes wrote on Dec 26^th, 2009 at 5:59pm:

Not just mammals. Geneticists also did a test on the birds as well; They've knocked out the FOXP2 gene, which caused serious dysfunctions of the one's singing... (reference here: http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.0050321)

Quote:
There is a layman information about FOXP2 available here: http://en.wikipedia.org/wiki/FOXP2 (and non-layman information about it here: http://ghr.nlm.nih.gov/gene=foxp2 ), which interacts with protein called CDBP1 ( http://en.wikipedia.org/wiki/CTBP1  or http://server5.xennexinc.com/v3//index.php?path=/GeneCard/card/CTBP1/5686e72e01c091f3175713cf05b7aded )

I vaguely remember learning about an early scientific theorist who believed that evolution was caused by immediate need. So if I were a fish and decided that I'd die from lack of nourishment in the lake, I could grow legs and go eat grass. I can't remember names, I'm sure someone here knows.