The earliest well-preserved American genomes are most closely related to modern Native American populations.

They are not more closely related to Australian Aboriginal peoples, or to African populations, or to ancient Europeans.

The genetic signatures of the first Americans are the genetic signatures of Native America.

This does not mean that all questions about early American morphological variation have been answered.

Why the skulls of early Americans show patterns of variation different from those of later populations is still a subject of active research.

The explanations that have been proposed — dietary changes, genetic drift within small founding populations, adaptation to different environments, developmental plasticity — are all plausible and may all be partly correct.