A Chunk of Denisovan DNA

Tibetans are uniquely suited to living at high altitudes where there's 40% less oxygen than at sea level. They're genetically similar to Han Chinese, except for one thing - a super-long string of DNA called EPAS1. It's that string that carries the traits that help them thrive, and now we know where they got it - from Denisovan Humans, a species we didn't even know EXISTED until we sequenced their genes from a finger bone four years ago!

Best guess, the ancestors of the Tibetans mated with the Denisovans, much like we mated with Neanderthals. (Some folks have 5% Neanderthal DNA in their genetic makeup.)

This stuff is so cool.