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[QUOTE]Originally posted by DD'eDeN: [QB] The region with the strongest associations was in and around the SLC24A5 gene, one variant of which is known to play a role in light skin color in European and some southern Asian populations and is believed to have arisen more than 30,000 years ago. This variant was common in populations in Ethiopia and Tanzania that were known to have ancestry from southeast Asia and the Middle East, suggesting it was carried into Africa from those regions and, based on its frequency, may have been positively selected. Another region, which contains the MFSD12 gene, had the second strongest association to skin pigmentation. This gene is expressed at low levels in depigmented skin in individuals with vitiligo, a condition where the skin loses pigment in some areas. "I still rememeber the 'ah ha!' moment when we saw this gene was associated with vitiligo," said Crawford. "That's when we knew we'd found something new and exciting." The team found that mutations in and around this gene that were associated with dark pigmentation were present at high frequencies in populations of Nilo-Saharan ancestry, who tend to have very dark skin, as well as across sub-Saharan populations, except the San, who tend to have lighter skin. They also identified these variants, as well as others associated with dark skin pigmentation, in South Asian Indian and Australo-Melanesian populations, who tend to have the darkest skin coloration outside of Africa. "The origin of traits such as hair texture, skin color and stature, which are shared between some indigenous populations in Melanesia and Australia and some sub-Saharan Africans, has long been a mystery." Tishkoff said. "Some have argued it's because of convergent evolution, that they independently evolved these mutations, but our study finds that, at genes associated with skin color, they have the identical variants associated with dark skin as Africans. "Our data are consistent with a proposed early migration event of modern humans out of Africa along the southern coast of Asia and into Australo-Melanesia and a secondary migration event into other regions. However, it is also possible that there was a single African source population that contained genetic variants associated with both light and dark skin and that the variants associated with dark pigmentation were maintained only in South Asians and Australo-Melanesians and lost in other Eurasians due to natural selection." Read more at https://archaeologynewsnetwork.blogspot.com/2017/10/genes-responsible-for-diversity-of.html#7GScshZBu5ffpee7.99 [/QB][/QUOTE]
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