A study identifies potential genetic adaptations among indigenous populations in Alaska, central Mexico, and the southeastern United States. Researchers have examined natural selection in humans around the world, but little is known about genetic adaptations in the indigenous peoples of North America. Austin W. Reynolds and colleagues analyzed DNA samples from 35 Alaskan Iñupiat, 47 individuals from central Mexico, and 68 individuals from closely related communities in the southeastern United States. Genes affecting blood thickness, fat storage, and eye/hair/skin pigmentation exhibited the strongest signals of selection in the Alaskan population, suggesting that a cold-resistant phenotype may be under selection, given that extended exposure to low temperatures increases blood thickness and the need to store fat. The Alaskan population may also be adapted to high latitudes, where exposure to ultraviolet radiation is low, rendering it difficult to maintain healthy levels of vitamin D in the body and favoring low levels of melanin in the skin. Strong signals of selection in genes related to immune response were detected among populations in central Mexico and the southeastern United States, where multiple epidemics of diseases introduced from Europe occurred during the colonial period. No signals of selection were shared among all three populations studied. The findings suggest that selective pressures varied among indigenous populations depending on population history and geography, according to the authors.
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Article #18-19467: "Comparing signals of natural selection between three Indigenous North American populations," by Austin W. Reynolds et al.
MEDIA CONTACTS: Austin W. Reynolds, University of California, Davis, CA; tel: 812-987-8857; email: < awreynolds@ucdavis.edu >; Deborah A. Bolnick, University of Connecticut, Storrs, CT; tel: 512-440-0964; email: < deborah.bolnick@uconn.edu >
Proceedings of the National Academy of Sciences