This migration had occurred during the late Pleistocene — the Ice Age — and the founding population had carried genetic signatures that distinguished them from other Asian populations, signatures that accumulated during a period of geographic isolation in the Beringian region.

But within this broad framework, enormous questions remained.

When exactly did the founding population move south of the ice?

Were there one or multiple founding migration events?

How quickly did people spread across the Americas?

When did the genetically distinct populations of North and South America diverge from each other?

The Spirit Cave Man’s genome, combined with the other fourteen genomes analyzed in the same study, shed light on several of these questions.

One of the most striking findings was the apparent speed of the initial spread across the Americas.