Sunday, September 18, 2011
Scientists have collected more evidence to suggest that ancient and modern humans interbred in Africa
Reanalysis of the 13,000-year-old skull from a cave in West Africa reveals a skull more primitive-looking than its age suggests. The result suggests that the ancestors of early humans did not die out quickly in Africa, but instead lived alongside their descendants and bred with them until comparatively recently. The skull, found in the Iwo Eleru cave in Nigeria in 1965, does not look like a modern human. It is longer and flatter with a strong brow ridge; features closer to a much older skull from Tanzania, thought to be around 140,000 years old. Prof Katerina Harvati from the University of Tuebingen in Germany used new digitizing techniques to capture the surface of the skull in detail. The new technique improved upon the original measurements done with calipers by letting researchers see subtler details about the skull's surface. "[The skull] has got a much more primitive appearance, even though it is only 13,000 years old," said Chris Stringer, from London's Natural History Museum, who was part of the team of researchers. "This suggests that human evolution in Africa was more complex... the transition to modern humans was not a straight transition and then a cut off." Prof Stringer thinks that ancient humans did not die away once they had given rise to modern humans. They may have continued to live alongside their descendants in Africa, perhaps exchanging genes with them, until more recently than had been thought. Separate research published recently suggests that genetic mixing between hominin species happened in Africa up to 35,000 years ago. I wonder if this mixing with more primitive species helps to explain why Africans are less intelligent than Europeans and Asians?