A recent article in Science News discusses evidence provided by genome sequencing that modern humans and Neanderthals interbred. Apparently people of European and Asian origin have about 4% of their DNA from Homo Neanderthalensis, Neanderthal Man, aka the Cave Man. People from Africa do not. African people are pure Homo Sapiens, Intelligent Man, i.e., modern human.
To be more clear about it, there were several waves of human migration from our common origin in Africa. Neanderthals migrated into Europe some tens of thousand years before anatomically modern humans. When modern humans moved into Europe and Asia, Neanderthals disappeared as an anatomically distinct group. Now we know that they were not entirely wiped out. The interbred with some of our ancestors.
This means that, contrary to racial doctrines that enjoyed some popularity among white people in the previous century, white people are the product of Africans mating with Neanderthals. White people are not only of mixed race, they are of mixed species. If, that is, Neanderthals continue to be regarded as a distinct human species, which they probably will not.
Anyway, all you white supremacists out there, if you want to know what a 100% pure human being looks like, he or she is black.