February 25 2015

12:00 LSB 2320

Emilia Huerta-Sanchez
School of Natural Sciences, UC Merced

Tibetans’ adaptation to high altitude, a genetic gift from archaic humans


As modern humans migrated out of Africa, they encountered many
different environmental conditions including temperature extremes, new
pathogens, and high altitude. These diverse environments have likely
acted as agents of natural selection and led to local adaptations. One
of the most striking examples in humans is the adaptation of
Tibetans to the hypoxic environment of the high-altitude Tibetan
plateau. A hypoxia pathway gene, EPAS1, was previously identified as
having the most extreme signature of positive selection in Tibetans,
and was shown to be associated with differences in hemoglobin
concentration at high altitude. Re-sequencing the region around EPAS1
in 40 Tibetan and 40 Han individuals, we find that this gene has a
highly unusual haplotype structure that can only be convincingly
explained by introgression of DNA from Denisovans or Denisovan-related
individuals into humans. Our findings illustrate that adaptation to
new environments may have been facilitated through admixture with
other hominin species, leading to a faster rate of adaptation.















































































































































































































































































































































































































































































































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