Genetic evidence of a recent Tibetan ancestry to Sherpas in the Himalayan region.

Sherpas living around the Himalayas are renowned as high-altitude mountain climbers but when and where the Sherpa people originated from remains contentious. In this study, we collected DNA samples from 582 Sherpas living in Nepal and Tibet Autonomous Region of China to study the genetic diversity of both their maternal (mitochondrial DNA) and paternal (Y chromosome) lineages. Analysis showed that Sherpas share most of their paternal and maternal lineages with indigenous Tibetans, representing a recently derived sub-lineage. The estimated ages of two Sherpa-specific mtDNA sub-haplogroups (C4a3b1 and A15c1) indicate a shallow genetic divergence between Sherpas and Tibetans less than 1,500 years ago. These findings reject the previous theory that Sherpa and Han Chinese served as dual ancestral populations of Tibetans, and conversely suggest that Tibetans are the ancestral populations of the Sherpas, whose adaptive traits for high altitude were recently inherited from their ancestors in Tibet.