Homo sapiens evolved within African, from several apparently separate and only occasionally intermixing populations. My intuition is that something extremely s

Homo sapiens evolved within African, from several apparently separate and only occasionally intermixing populations. My intuition is that something extremely similar happened for Neanderthals in Europe and Denisovans in Asia. After speciating, Denisovans and Neanderthals migrated at least within Eurasia, and those populations intermixed. At least as early as that was happening, Homo sapiens started migrating out of Africa, and intermixed with the Homo genus populations they encountered. At some later point, distinctly Neanderthal, Denisovan, and Neanderthal/Denisovan populations apparently died off.