Tibetans have genes for high mountains

Copenhagen biologist helps find gene for high altitude survival. The Tibetans have evolved the gene in record time

by Mike Young

Tibetans have an ability to survive, and thrive, at high altitudes, while lowlanders are afflicted by altitude sickness. Traditionally this has been seen as solely the result of the environmental influence of their spending time in the high mountains.

But University of Copenhagen research just published in the periodical Science proves that the Tibetan altitude advantage has been adapted in their genes too.

Tibetans have developed the ability to manage with the 40 per cent lower concentrations of oxygen at their home altitudes of over 4,000 metres, the researchers say.

An international team which includes members from the Department of Biology, University of Copenhagen compared the genes of 50 Tibetans and 40 lowland Han Chinese people.

Fastest gene change

There were more than 30 genes with DNA mutations which were more prevalent among the ethnic Tibetans than among the Han-Chinese. More than half of these genes are known for their connection to oxygen consumption. One of the genes, EPAS1, also known as the super-athlete gene, was particularly interesting for the scientists, as it had mutated within the last 3,000 years.

For Rasmus Nielsen, Professor in evolutionary biology at the Department of Biology, University of Copenhagen the results are remarkable.

»It is the fastest genetic change ever described in Man. The mutation must have had a large effect on human survival at altitude to be the cause of such a change,« he says.

Pre-adapted

To the University Post, Rasmus Nielsen explains that adaptation to the high mountain air can take two forms:

The physiological adaptation that takes place for both Tibetans and lowlanders in the course of the days and weeks after climbing to a higher altitude. Tibetans, just like lowlanders, get altitude sickness when suddenly moving to higher altitudes before a proper adaptation takes places.

Secondly, the new research points to a second type of adaptation, previously not proven - through inheritance and the genes.

»When we go high, we compensate by producing a lot of hemoglobin to transport oxygen to the body's tissues. But there is a cost to that. The blood goes thick. It turns out that the Tibetans don't have to produce that much hemoglobin,« he says.

You could say that they are 'pre-adapted' to adapting to altitudes, he explains.

The EPAS1, 'super-athlete' gene is also known to be present in successful athletes in endurance sports.

miy@adm.ku.dk

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