About 2,750 years ago, members of the ethnic group known as Han Chinese began to migrate to the Himalayas. They began to live at altitudes above 13,000 feet, where oxygen levels are 40% lower than sea level.
These are the people who became the Tibetans. They evolved an animistic religion called Bo and in the process of aclimatazion, they evolved as a group faster than any other known population on earth.
In the short time they have lived at high altitudes, they have adapted to lower oxygen, atmospheric conditions and air pressure which would severely incapacitate most other humans.
Scientists have been abble to track the DNA mutation of over 30 genes which deal specifically with how the body uses oxygen.
They did this by comparing the samples from modern Tibetans with the present lowland Han population, which still share the common genotype.
"For such a very strong change, a lot of people would have had to die simply due to the fact that they had the wrong version of a gene," said Rasmus Nielsen, a professor of integrative biology at Berkeley who led the statistical analysis. This evolutionary history can also be related to the very unique religious beliefs of Bo, which has become a fusion religion, Modern Tibetan Bhudism. The meditative techniques which can be used to obtain an incredible amount of physical control over the human body, defying rational explanations by modern scientists as well, are another aspect of the evolution of the Tibetans.
Scientists believe that the knowlege gained by the study of Tibetan genetic mutation relating to oxygen use can be very beneficial in understanding how the body deals with decreased oxygen and diseases associated with oxygen deprivation in the womb according to the University of California-Berkeley website.