The Tibetan people have inherited variants of five different genes that help them live at high altitudes, with one gene originating in the extinct human subspecies, the Denisovans. Dr. Hao Hu and Dr. Chad Huff of the University of Texas, Houston, and colleagues report these findings in a new study published online on April 27, 2017 in PLOS Genetics. The open-access article is titled “Evolutionary History of Tibetans Inferred from Whole-Genome Sequencing.” The people of Tibet have survived on an extremely high and arid plateau for thousands of years, due to their amazing natural ability to withstand low levels of oxygen, extreme cold, exposure to UV light, and very limited food sources. Researchers sequenced the whole genomes of 27 Tibetans and searched for advantageous genes. The analysis identified two genes already known to be involved in adaptation to high altitude, EPAS1 and EGLN1, as well as two genes related to low oxygen levels, PTGIS and KCTD12. They also picked out a variant of VDR, which plays a role in vitamin D metabolism and may help compensate for vitamin D deficiency, which commonly affects Tibetan nomads. The Tibetan variant of the EPAS1 gene originally came from the archaic Denisovan people, but the researchers found no other genes related to high altitude with Denisovan roots. Further analysis showed that Han Chinese and Tibetan subpopulations split as early as 44 to 58 thousand years ago, but that gene flow between the groups continued until approximately 9 thousand years ago.
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