Objects and ideas can travel without people moving.

The spread of an agricultural technique, a pottery style, or an administrative practice can happen through a chain of copying and borrowing, without any individual person traveling the full distance between the originating culture and the adopting one.

But DNA can only be present in a new location if people with that DNA moved there and had children there.

The 20 percent Fertile Crescent ancestry in NUE001 is evidence that some people — not necessarily many, not necessarily a large migration, but real human beings — moved from the eastern Fertile Crescent into Egypt at some point in the period before the Old Kingdom.

They settled, integrated into the Egyptian population, and left a genetic trace that survived in the teeth of a man buried in Nuwayrat four and a half millennia ago.