Tibetans inherited 'super gene' from extinct humans to survive life on the Roof of ... - The Independent

As the highest region on the planet, the Tibetan Plateau is often referred to as the Roof of the World. An average elevation in excess of 4,500 metres leaves most people struggling in the oxygen-poor air, but for the area’s Tibetan inhabitants life there is as natural as, well, breathing.

Now scientists think they discovered exactly how the Tibetans cope, tracing a specialized gene found in modern-day inhabitants of the region back to one of humanity’s extinct ancestors – a n ancient species known as the Denisovans.

The gene is called EPAS1 and it helps regulate the body’s responses to low-oxygen atmosphere. When most humans are exposed to these conditions their bodies start producing extra red blood cells to circulate more oxygen around the body. However, this creates thicker blood that’s harder to pump, exacerbating a range of problems from hypertension to the risk of strokes.

EPAS1 stops this ‘overreaction’, leading some scientists to refer to it as ‘the athlete gene’. Humans that do have it tend to perform better at certain aerobic-intensive sports but for Tibetans it’s just part an ordinary part of their genetic makeup.

In the high altitude regions of the Tibetan Plateau air contains 40 per cent less oxygen.

So where did EPAS1 come from? A new study from the University of Berkeley published in the journal Nature this Wednesday suggests it comes from the Denisovans – an early human ancestor that was only discovered four years ago when scientists sequenced the DNA from a finger bone found in a Siberian cave.

Denisovans are thought to have been knocking around on the earth for tens of thousands of years longer than modern humans. When the two species bred together some of our ancestors inherited the EPAS1 gene and were able to thrive in the Tibetan plateau – a much faster method of adapting to the high altitude environment than waiting around for evolution to kick in.

The researchers also compared the Tibetan genome with that of the neighbouring Han Chinese, and found that only 1 in 20 of the Han possessed EPAS1. “They are extremely differentiated from each other, which is something you only see with very strong or very recent selection,” Rasmus Nielsen, an author of the study, told the LA Times.

The discovery confirms that contrary to past theories that our ancestor simply out-survived and out-lived more ‘archaic’ humans such as Neanderthals and Denisovans, the interbreeding of the different species helped modern humans to survive and adapt in different environments around the world.

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