Nearly 11,000 years ago, a man died in what is now Nevada. Wrapped in a rabbit-skin blanket and reed mats, he was buried in a place called Spirit Cave.

Now scientists have recovered and analyzed his DNA, along with that of 70 other ancient people whose remains were discovered throughout the Americas. The findings lend astonishing detail to a story once lost to prehistory: how and when humans spread across the Western Hemisphere.

The earliest known arrivals from Asia were already splitting into recognizably distinct groups, the research suggests. Some of these populations thrived, becoming the ancestors of indigenous peoples throughout the hemisphere.

But other groups died out entirely, leaving no trace save for what can be discerned in ancient DNA. Indeed, the new genetic research hints at many dramatic chapters in the peopling of the Americas that archaeology has yet to uncover.