A serial founder effect model for human settlement out of Africa
Omkar Deshpande, Serafim Batzoglou, Marcus W. Feldman, L. Luca Cavalli-Sforza
The increasing abundance of human genetic data has shown that the geographical patterns of worldwide genetic diversity are best explained by human expansion out of Africa. This expansion is modelled well by prolonged migration from a single origin in Africa with multiple subsequent serial founding events. We discuss a new simulation model for the serial founder effect out of Africa and compare it with results from previous studies. Unlike previous models, we distinguish colonization events from the continued exchange of people between occupied territories as a result of mating. We conduct a search through parameter space to estimate the range of parameter values that best explain key statistics from published data on worldwide variation in microsatellites. The range of parameters we use is chosen to be compatible with an out-of-Africa migration at 50–60Kyr ago and archaeo–ethno–demographic information. In addition to a colonization rate of 0.09–0.18, for an acceptable fit to the published microsatellite data, incorporation into existing models of exchange between neighbouring populations is essential, but at a very low rate. A linear decay of genetic diversity with geographical distance from the origin of expansion could apply to any species, especially if it moved recently into new geographical niches.
I noticed this when nosing through Dienekes blog (once a week on average). This pretty much supports my ‘weak eden’ stance, although I’d certainly say huh? over the OOA date as being way to recent (Australoids were entering Oz and South America about 50k ago, and the Liujiang skull is at least 68k old). I’m not sure what kind of difference an older exit date would make to their study though. If I ever find the entirety of this paper I’ll post it.