tag:blogger.com,1999:blog-7785493.post418855431600223620..comments2024-01-04T04:11:55.717+02:00Comments on Dienekes’ Anthropology Blog: High genetic differentiation between populations often driven by classic selective sweepsDienekeshttp://www.blogger.com/profile/02082684850093948970noreply@blogger.comBlogger1125tag:blogger.com,1999:blog-7785493.post-28325653707669181752014-05-30T01:46:04.087+03:002014-05-30T01:46:04.087+03:00Yeah, the quote below, from the full PDF, points t...Yeah, the quote below, from the full PDF, points to the deep problem with this kind of analysis. Larger populations logically don’t make selection more efficient. The efficiency should go the other way, especially with some of the traits mentioned (like blue eyes) where there’s possible founder effects, etc. Identifying “high differentiation” is more about effect than it is about cause. And so it doesn’t tell us how the current situation got that way. And certainly can’t tell us if the selection was functional or an accidental one that bloomed because of a founder effect or local circumstances. The African result also points to a problem in the data.<br /><br />“SNP ascertainment in African populations has been less thorough than in<br />European populations, and so analyses based on known SNPs have been biased against<br />discovering highly differentiated sites in Africans. The identification of HighD sites from full<br />sequence data, however, is unaffected by recombination or ascertainment, and the lower<br />number of HighD sites in Africa (25 vs 110 each in EUR and ASN) supports the hypothesis of<br />less positive selection of this type, despite the larger effective population size which should<br />make selection more efficient.”LivoniaGhttps://www.blogger.com/profile/05589404219598229067noreply@blogger.com