In contrast, the mtDNA from the younger Australian fossils closely resembles that of living humans. If so, he says, the absence of Neandertal mtDNA in living humans does not rule out the possibility that they contributed to our gene pool. Other researchers are reserving judgment until the results are replicated in an independent lab, citing the possibility of contamination. In truth, the mtDNA studies are additionally problematic because the history of a single gene does not necessarily reflect the history of a population. Different genes can tell different stories, and mtDNA, as far as human evolution researchers are concerned, represents only one gene.
Fossils thus remain very much a part of the human origins debate.
To that end, the second study published this month calling the Out of Africa replacement scenario into question focused on bones. Both groups apparently exhibit traits seen in their Middle Eastern and African predecessors. But the early modern specimens from Central Europe also display Neandertal traits, and the early modern Australians showed affinities to archaic Homo from Indonesia. The fossils clearly show that more than one ancient group survived and thrived. Eventually, multiregionalists argue, Neandertals and other archaic humans as entities disappeared through interbreeding.