This picture of a structured founding population is consistent with the deep ancestral structure explanation of Population Y.

The Beringian Standstill and What It Created

One of the most important developments in the scientific understanding of early American settlement over the past twenty years is the accumulation of evidence for what has been called the “Beringian standstill” — a period during which the ancestral Native American population was isolated in the Beringia region, neither moving back into Asia nor yet moving into the Americas, for a period of time that may have lasted several thousand years.

The evidence for this standstill comes from multiple sources.