A study on human remains found in the Iwo Eleru cave in Nigeria, West Africa, shows that Stone Age humans in the area shared characteristics with much older human relatives. Palaeontologists leading the study believe their findings provide evidence that modern humans and older subspecies of human might have coexisted and even crossbred in Africa. The findings add weight to theories that ancient species of human lived alongside the anatomically modern humans after they first appeared in Africa 200,000 years ago.Quoted in the article is Chris Stringer, one of the progenitors of the Out-of-Africa replacement model of modern human origins which was based on mitochondrial DNA studies done in the late 1980s.The article continues:
Professor Stringer said: "The majority view was that once modern humans emerged in Africa 150,000 years ago, it was kind of the end of the story and modern humans took over. "I think the reality is that the ancestral forms didn't just disappear but hung around alongside those that had evolved into modern humans. "Somewhere lurking in bits of Africa were these more archaic people and we are starting to get a picture of that."I suspect that it is going to get very hard to pin down exactly where Homo sapiens starts. It is becoming more and more clear that anatomically modern Homo sapiens and archaic Homo sapiens went for the occasional “roll in the hay.” If so, as I pointed out earlier, there simply was no “speciation event.” This goes more to supporting the multiregional evolution model, as it applies to Africa, in which there was selection for more modern genes. This model may also apply to Europe, with the mixing of modern humans and archaic humans there. I suspect that this will spur reexamination of the early modern material from there, such as Mladeč, where the material dates from the Early Würm/Late Würm interglacial period.