On the mountainous Tibetan Plateau, small groups of nomadic herders still make a living two miles or more above sea level. Most of us would be poorly-equipped to deal with that altitude for long periods of time, but the Tibetans there have unique genetic adaptations that let their bodies function in the thin air.
Mysteriously, those genes seem to come from another species of human, the Denisovans, a little-understood group of hominins who died out tens of thousands of years ago. Until now, Denisovan remains had only been found in a single cave, at low altitude. That left the extinct species' high-altitude genes, like much else about their people, a puzzle. But the discovery of new Denisovan remains in Tibet might begin to change that.
Back in 1980, a monk praying in a cave found a mysterious human mandible, or jawbone, of which only the right half survives. Now scientists have re-examined that bone and say it came from a Denisovan. Their study appears Wednesday in the journal Nature.
And it shows that this particular Denisovan died in the area some 160,000 years ago, according to uranium-thorium dating of a carbonate deposit that grew around the jawbone after it was buried. The Denisovans, a sister lineage to Homo sapiens, were only discovered to be a new lineage of humans in 2010, and their genome was first sequenced not long afterward. However, the physical evidence for their existence is based on just a few bones, and accompanying DNA sequences, that were found at a place called Denisova Cave in Siberia.
