Spelunking for Genes

Debra Bradley Ruder in Harvard Medicine:

Russian archaeologists have been excavating Denisova Cave for three decades, but it wasn’t until recently that they unearthed a pea-sized pinky bone from a young girl who, they think, lived some 30,000 to 50,000 years ago. Remarkably, it contained enough genetic material to salvage and study.

That bone, along with an oversized adult molar, helped Reich and his colleagues at HMS and the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, identify a previously unknown hominin who was neither Neanderthal nor modern human. This “archaic” group, dubbed the Denisovans, after the cave, apparently inhabited a large swath of Asia and—like Neanderthals—mated with modern humans. Although both Neanderthals and Denisovans eventually died out, traces of their genes live on in some populations today.

These discoveries are adding pieces to the puzzle of how humans evolved and where and when prehistoric people roamed the Earth. The work also reinforces the notion that population mixing has been the rule, not the exception, throughout human history. For geneticists like Reich, however, the greatest promise of this research might be in learning whether the genes inherited from these ancient people help protect today’s humans from disease.

More here.