While we're at it, what is your take on the fact that humans bottlenecked after Toba, and other animals did not? Neandertal is known to have much more genetic variation than HSS.
I think there must be more to the story.
Beags, yes I am a multi-regionalist but with a twist. I do believe the genetic dispersal OOA has merit; however, only to the extent that in a very short period of time the African lineage overran the rest of the world post-Toba and that any hybrid combinations would have been "washed out" by genetic drift over scores of generations. We haven't found too many of the dispersal survivors, only some late (24,000bp) Neanderthals and late-surviving Java
H. erectus, but already Trinkaus is certain that he has found hybrids. Notice I didn't mention
H. floriensis since the jury is still out on the hobbits.
Toba reduced the population of breeding adults in Africa. It probably did the same for
H. neanderthalis in Eurasia and
H. erectus elsewhere. That event more than likely gave surviving Africans an advantage since they had a sophisticated culture and language going for them in relation to the other groups when they dispersed after 70,000bp. Better communication over long distances was an advantage, and higher rates of breeding probably did the rest. Like anything, this was a case of being in the right place at the right time ... a fortunate occurrence for
H. sapiens and not so fortunate for any others.
You know that a very small percentage of increase in birth rates or longevity will result in populations being displaced over a few thousand years. Regardless, I still think there were Neanderthals in the woodpile and some genetic contribution that has yet to surface in a definitive way in the nuclear genome.