Testing multiregionality of modern human origins

In order to examine the possibility of multiple founding populations of ana tomically modern Home sapiens, we collected DNA sequence data from 10 X-chr omosomal regions, 5 autosomal regions, and 1 Y-chromosomal region, in addit ion to mitochondrial DNA. Except for five regions which are genealogically uninformative and two other regions for which chimpanzee orthologs are not available, the ancestral sequence and population for each of the remaining regions were successfully inferred. Of these 10 ancestral sequences, 9 occu rred in Africa and only I occurred in Asia during the Pleistocene. Computer simulation was carried out to quantify the multiregional hypothesis based solely on the premise that there was more than one founding population in t he Pleistocene. Allowing the breeding size to vary among the founding popul ations, the hypothesis may account for the observed African ancestry in 90% of the genomic regions. However, it is required that the founding populati on in Africa was much larger than that outside Africa. Likelihood estimates of the breeding sizes in the founding populations were more than 9,000 in Africa and less than 1,000 in outside of Africa, although these estimates c an be much less biased at the 1% significance level. If the number of Afric an ancestral sequences further increases as more data accumulate in other g enomic regions, the conclusion of a single founding population of modern H. sapiens is inevitable.