Why Isn’t There A Neanderthal-Human Hybrid?

Neanderthals presided in Eurasia and modern day humans lived in Africa. They both came from a common ancestor. Neanderthals developed barrel chests, large skulls and strong hands while modern humans acquired shorter faces, a prominent chin and slender arms. Thousands of years later when modern humans left Africa they bred with Neanderthals. Only four percent of the genes of non-Africans are Neanderthal origin so you might ask, where did all the Neanderthal DNA go? Due to difference in population size between Neanderthals and modern humans and the fact that small populations have less natural selection, the DNA’s outcome was greatly affected. According to Graham Coop, a genetics professor at the University of California, “Neanderthals have this small population over hundreds of thousands of years, presumably because they’re living in very rough conditions.” This small population size would mean that the Neanderthals were more interbred than the modern humans which would lead to more mutations. It was found by David Reich that natural selection was actually working against Neanderthal DNA. All together, “a hybrid of Neanderthals and modern humans would have been less fit than pure humans” which was stated by Kelly Harris, a postdoctoral at Stanford University. Natural selection stopped such a Neanderthal-hybrid from occurring.