One of the main claims of the Out of Africa Hypothesis was that they could not interbreed with Neanderthals. Yes the last major mutation to be adopted accost all regions came from Africa, but the hypothesis that man can from Africa alone and dominated the globe is wholly false. It's amazing that people still parade the Out of Africa Hypothesis as a valid when one of it's own tests for falsification dismantled it.
A mt-DNA analysis on aboriginals in Australia has shown that the mt-DNA of aboriginals in Australia is similar to that of the modern humans that left Africa and replaced the Homo Erectus populations. This is significant because it was previously hypothesized that there was gene flow between archaic Homo Sapiens in the area and Homo Erectus, this would suggest that Multiregional theory is correct, however the mt-DNA has proven that there was in fact very little interbreeding, further validating that Out of Africa/Replacement theory is in fact correct.