Another nail in the coffin of the multiple-origins theory?

While mitochondrial sequences can be used to probe the time and place of the mitochondrial 'Eve,' nuclear genes can be used to ask a slightly different question: when did humans (members of the genus Homo) or their hominid precursors (the hominids) first leave Africa and fan out over Asia and Europe? If they did so recently, it seems likely that there was a recent African origin of our species, Homo sapiens, rather than multiple origins in various parts of the Old World. A recent paper uses minisatellite data to make the argument that the departure from Africa happened very recently indeed. An alternative explanation for the data is that there was no single and irreversible departure from Africa, but that some peoples migrated back and forth between Africa and the rest of the Old World over the last few tens of thousands of years. For this and other reasons, putting a single date on the farewell to Africa remains problematical.