Tibetannet

Tibetan children [Photo/China Tibet Online]

The average altitude of the Qinghai-Tibet Plateau is over 4,000 meters. The thin air here can make outside travelers feel slight illnesses. Nevertheless, Tibetan people have been able to live in this environment generation after generation.

Recently, scientists from the Kunming Institute of Animal Studies, which belongs to the Chinese Academy of Science, have discovered the secret that allows Tibetan people to adapt to the extremely-low-oxygen environment on the plateau. It is the HMOX2 gene. Related research findings have recently been published in an international core journal titled Human Genetic Variation.

According to the research team leader Su Bing, the group has been committing themselves to the study of Tibetan people’s genomes for the last ten years. In order to move a step further in researching the functional effect that the HMOX2 gene has on Tibetan people’s high-altitude adaptation ability, the scientists have made a comparative study and analysis regarding the HMOX2 gene of the Tibetan community and that of the Han community living in low altitude areas. As a result, they discovered a functional genetic mutation. This sort of functional genetic mutation is observed obviously much more frequently amongst the Tibetan people than amongst the Han people.

"It was the same natural process described in Darwin’s theory of natural selection that led to this enriching genetic mutation amongst the Tibetan people. Because the HMOX2 gene takes part in the metabolization of hemachrome, it plays an important role in low-oxygen adaptation amongst Tibetan people. Furthermore, HMOX2 is especially important in the adjustment and control of the hemoglobin levels of Tibetan people", said Su Bing.

Long term exposure to low-oxygen conditions will lead to overgrowth of red cells in the bodies of those who are not able to adapt to a given low-oxygen environment. This may ultimately cause an extreme overgrowth which results in a "red blood cell over-proliferation disease". Yet, the functional genetic mutation of the HMOX2 gene can speed up the metabolization of the uncalled-for hemachrome in the bodies of the Tibetan people. This helps the Tibetan people living in high-altitude environments maintain a comparatively low hemoglobin level, and they thereby avoid the side effects brought by overgrowth of red blood cells, and thus the gene can protect Tibetan people.

"Adaptation to the low-oxygen living environment of Tibetan people is the outcome of the combined actions of many different elements. Our research is merely a start on a long journey", said Su Bing. "This research project can help us better understand the unique ability of the Tibetan people to adapt. It also brings us some enlightenment in efforts to prevent and cure high altitude diseases".