One of the most important contributions of the 2020s work is a better characterization of the internal genetic diversity of the ancient Native American founding population.

Early work had treated the founding population as relatively uniform, differing from later populations primarily in having experienced less genetic drift over time.

More recent work has found evidence of finer internal structure within the early Native American population — distinct genetic lineages that diverged early in the history of the founding population and that contributed differentially to different parts of the Americas.

This finding is directly relevant to the Population Y debate.