They were not a mystery race or an alien intrusion or a lost civilization in any sensational sense.

They were hunter-gatherers who lived on a high Colombian plateau for generations, developed a genetic character distinct from other South Americans, and left a record — in bone and ultimately in DNA — that persisted until science could finally read it.

The reading has been done.

The story is partial — incomplete in the four-thousand-year gap, incomplete in the populations not yet sampled, incomplete in the mechanisms it cannot identify.

But it is real.