The most influential genetic models suggest that the founding population of the Americas — the population ancestral to virtually all Native Americans — became genetically isolated from its Asian relatives somewhere between 23,000 and 17,000 years ago.

During this period, the population was isolated in Beringia or in the immediately adjacent parts of Alaska, without genetic exchange with the populations to the west (in Siberia and Asia) or to the south (in the interior of North America, which was still largely covered by ice).

This period of isolation is sometimes called the “Beringian standstill” — a period when the founding population was small, geographically confined, and accumulating the distinctive genetic signature that differentiates Native Americans from their closest Asian relatives.

Following the standstill, as the ice sheets began to retreat and routes into the interior of North America became accessible, the population spread southward rapidly.