DNA analysis of Homo sapiens remains from 40,000 years ago found that they had up to 9% Neanderthal DNA, and analysis of modern people showed that they have anything from 1 to 4% Neanderthal DNA. Of course, that can only be the result of interbreeding between Homo sapiens and Neanderthals. However, this does not apply to modern humans who originate from Africa—they have no Neanderthal DNA. This appears to confirm that interaction between Homo sapiens and Neanderthals took place outside Africa and involved only Homo sapiens that had left Africa.
