The stories those people told, the names they gave each other and to the landscapes they inhabited, the specific beliefs that led them to bury children with ochre and beautiful tools — all of this is inaccessible in any direct form.

Ancient DNA is one of the tools that is beginning to recover some of what the absence of written records has obscured.

By comparing ancient genomes from different time periods and locations, researchers can reconstruct — imperfectly, with significant uncertainty, but meaningfully — the broad patterns of how populations moved, diverged, mixed, and were replaced over the period of deep American prehistory.

Population splits can be roughly dated.