Rule -> RE: Aids epidemic nearing its end? (7/27/2012 3:15:24 PM)
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ORIGINAL: Hillwilliam Actually, Rule is quite incorrect. Oh? [:-] quote:
ORIGINAL: Hillwilliam Most, if not all, lethal genetic diseases are recessives. This means that someone can be a carrier and totally unaffected. The only way the allele expresses itself is if both parents are carriers. Then, typically, one in 4 of the offspring show the condition. In the case of sex linked diseases, half of the males will show the disease. The important thing to remember is that carriers will still pass the allele to a significant portion of their offspring ensuring that the allele will never be eliminated from the population. Quite. It indeed is unlikely that deleterious alleles will ever all be eliminated from the population. However, considering that the frequency of deleterious alleles in non-cricumcising populations of Christian European descend are six times lower than in populations that have been practising circumcision for many generations, it is clear that the frequencies of such deleterious alleles in the gene pool of a population can be drastically reduced. The only requirement to enable this reduction, is to not circumcise. quote:
ORIGINAL: Hillwilliam There are also some genetic diseases that, while frequently lethal in the homozygous form, are advantageous in the heterozogous. An example is the sicle cell trait which confers immunity to malaria in the heterozygous form. Quite. One of my old hypotheses is that if the frequency of a deleterious allele is higher than 1 in a thousand (if I remember correctly), that such an allele may confer such an advantage. Whereas if it is smaller, it confers no such advantage. Also, a deleterious allele (or the gene that codes for another protein that it associates with) might - hypothetically - experience another mutation that improves upon the wildtype normal allele. Unlikely, but possible. quote:
ORIGINAL: Hillwilliam Some folks should just leave the biology and genetics to those who actually have a semblance of education in the area.[8|] Pff. There are not a lot of people who can do better in biology examinations than me, provided that I have had some time to study the subject(s).
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