They had developed the knowledge of the plateau’s seasonal patterns, the habits of its animals, the locations of reliable water sources and the best spots for hunting and gathering across the mountain year.

That knowledge would have been transmitted from parents to children over generations, accumulated into the specialized ecological intelligence that hunter-gatherer communities in high-altitude environments around the world characteristically develop.

They were, by any reasonable measure, a successful population — one that had lived on this demanding plateau for generations, had developed the physiological adaptations and cultural knowledge that high-altitude life requires, and had established recognizable patterns of settlement and subsistence.

And then, at some point in the following two to four thousand years, the genetic signature that identifies them as a distinct lineage stopped appearing in the archaeological record of the plateau.