They were here at the beginning.

They are here now.

That is what the genome of a six-week-old infant, buried in a hearth in the interior of Alaska in the early Holocene, ultimately tells us about the first Americans.

Everything else is detail.

Important detail.

Scientific detail.

The kind of detail that the field will be refining for decades.

But detail in service of a conclusion that one infant’s genome made as clear as ancient DNA can make anything: