May 15, 2005

More on the beachcomber hypothesis

John Hawks raises many alarm bells to the newer single coastal route Out of Africa hypothesis:
Okay, hmm...let me get this straight: modern humans had uber-technology to float across the Red Sea, kill mammoths, and outcompete every archaic human in every ecology they had occupied for a half million years or more, but they couldn't manage to move in 10,000 years across a semi-desert? And let's not forget the "modern" humans that get thrown under the bus in this scenario -- Skhul, Qafzeh, Liujiang -- either they don't qualify as "really" modern, or they've been misdated. Oh, and, there is the slight problem that no other locus provides any evidence of this pattern of population movement -- even the Y chromosome -- and many are not consistent with it.
John's entire post is interesting to read, and one wonders who reviewed this paper before it appeared in Science: the scenario proposed by the authors is certainly plausible, but mere plausibility is not science, nor does a study of the mitochondrial makeup of isolated Malaysian aboriginals establish that humans left Africa in a single migration that followed the coast at a pace of 4km/year.

Let's hope that there will be less of this in the future:
The Genographic Project is a major expansion of earlier work by Spencer Wells, a population geneticist and explorer-in-residence at the National Geographic Society, who used DNA from about 10,000 people to trace mankind's history to a tribe of hunter-gatherers in Africa 60,000 years ago.
and more attention to "details" such as this:
These indicate a more recent ancestry of the NRY at 59000 years (95% CI = 40000± 140000) than previously estimated at 134250-44980 years based on 13 mutational events and constant population size (Karafet et al. 1999).

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