A red blood cell production controlling gene evolved quickly to enable Tibetans to tolerate high altitudes, suggest researchers.
The team compared the DNA of 50 Tibetans with that of 40 Han Chinese and found that there were 34 mutations in Tibetans in the 2,750 years since the populations split, the Guardian reported.
The study also found that more fifty per cent of these changes are related to oxygen metabolism.
The researchers looked at specific genes responsible for high-altitude adaptation in Tibetans.
Professor Rasmus Nielsen of the University of California Berkeley, who took part in the study, said that they found a list of 20 genes showing evidence for selection in Tibet - but one stood out: EPAS1.
The gene, which codes for a protein involved in responding to falling oxygen levels, and is linked with improved athletic performance in endurance athletes, could be the key to Tibetan adaptation to life at high altitude.
The mutation that is believed to affect red blood cell production was present in only 9 per cent of the Han population, but was present in 87 per cent of the Tibetans.
The study has been published in the journal Science.