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Latest on your blood

By JW Dowey - 03 Jul 2014 8:5:19 GMT
Latest on your blood

Tibet has given us beautiful vistas such as the magnificent ancient Potala Palace in Lhasa, home of the Dalai Lama till 1959. Now, Tibetans have even more to contribute to the world, in the form of one small gene; Lhasa image; Credit: © Shutterstock

The Denisovans have been in our news several times. They are the obscure Asian group of "pre-humans" whose remains are found in mountain caves in Northern Asia, related but distinct from the Neanderthals. Both groups gave way to the Homo sapiens groups as they emerged, "out of Africa."

Now research at BGI . Shenzhen in China reveals a secret that this group had. When we interbreed with them, some of our offspring retained, by selection, a useful gene, EPAS1, that gave us an advantage. The only people still retaining this gene are Tibetans, living at altitudes up to 13,000 feet above sea level. At this great height, your blood usually thickens and can't supply you with oxygen, leading all of us to suffer from breathlessness- except for true Tibetans, that is. Genome research is certainly now leading us to exciting new possibilities!

When oxygen levels drop, EPAS1 triggers the production of more haemoglobin. Just like high-altitude training for athletes, where they gain a boost in oxygen absorption with an increase in haemoglobin, this gives Tibetans an advantage. This will have been crucial in Tibetan history, in any battle at high altitude for example. They couldn't lose! The EPAS1 however is carefully-crafted to increase the red blood cells less than in the normal human phenotype. Instead of thicker blood, Tibetans have more oxygen but none of the side effects, especially low birth weight babies and high infant mortality.

Emilia Huerta-Sánchez, Xin Jin, and their colleagues from Iowa. Lhasa, California, Saudi Arabia, Copenhagen, Macau, Hong Kong and many other Chinese institutions present this new discovery today in the journal Nature as- Altitude adaptation in Tibetans caused by introgression of Denisovan-like DNA.

Professor Rasmus Nielsen of the University of California/Berkeley puts it all in context for us "The only reason we can say that this bit of DNA is Denisovan is because of this lucky accident of sequencing DNA from a little bone found in a cave in Siberia. We found the Denisovan species at the DNA level, but how many other species are out there that we haven't sequenced?"

So now we can wait for evidence that the Neanderthals gave us a lot of useful stuff that we still carry around with us!