11. |
- Romero, Irene Gallego, et al.
(författare)
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Herders of Indian and European Cattle Share Their Predominant Allele for Lactase Persistence
- 2012
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Ingår i: Molecular biology and evolution. - : Oxford University Press (OUP). - 0737-4038 .- 1537-1719. ; 29:1, s. 248-259
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Tidskriftsartikel (refereegranskat)abstract
- Milk consumption and lactose digestion after weaning are exclusively human traits made possible by the continued production of the enzyme lactase in adulthood. Multiple independent mutations in a 100-bp region-part of an enhancer-approximately 14-kb upstream of the LCT gene are associated with this trait in Europeans and pastoralists from Saudi Arabia and Africa. However, a single mutation of purported western Eurasian origin accounts for much of observed lactase persistence outside Africa. Given the high levels of present-day milk consumption in India, together with archaeological and genetic evidence for the independent domestication of cattle in the Indus valley roughly 7,000 years ago, we sought to determine whether lactase persistence has evolved independently in the subcontinent. Here, we present the results of the first comprehensive survey of the LCT enhancer region in south Asia. Having genotyped 2,284 DNA samples from across the Indian subcontinent, we find that the previously described west Eurasian -13910 C>T mutation accounts for nearly all the genetic variation we observed in the 400- to 700-bp LCT regulatory region that we sequenced. Geography is a significant predictor of -13910*T allele frequency, and consistent with other genomic loci, its distribution in India follows a general northwest to southeast declining pattern, although frequencies among certain neighboring populations vary substantially. We confirm that the mutation is identical by descent to the European allele and is associated with the same >1 Mb extended haplotype in both populations.
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12. |
- Yunusbayev, Bayazit, et al.
(författare)
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The Caucasus as an Asymmetric Semipermeable Barrier to Ancient Human Migrations
- 2011
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Ingår i: Molecular biology and evolution. - : Oxford University Press. - 0737-4038 .- 1537-1719. ; 29:1, s. 359-365
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Tidskriftsartikel (refereegranskat)abstract
- The Caucasus, inhabited by modern humans since the Early Upper Paleolithic and known for its linguistic diversity, is considered to be important for understanding human dispersals and genetic diversity in Eurasia. We report a synthesis of autosomal, Y chromosome, and mitochondrial DNA (mtDNA) variation in populations from all major subregions and linguistic phyla of the area. Autosomal genome variation in the Caucasus reveals significant genetic uniformity among its ethnically and linguistically diverse populations and is consistent with predominantly Near/Middle Eastern origin of the Caucasians, with minor external impacts. In contrast to autosomal and mtDNA variation, signals of regional Y chromosome founder effects distinguish the eastern from western North Caucasians. Genetic discontinuity between the North Caucasus and the East European Plain contrasts with continuity through Anatolia and the Balkans, suggesting major routes of ancient gene flows and admixture.
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