In light of the recent work on the acceleration of human evolution due to increased population size, this paper in Genetics, Inferring Human Population Sizes, Divergence Times and Rates of Gene Flow From Mitochondrial, X and Y Chromosome Resequencing Data:
We estimate parameters of a general isolation-with-migration model using resequence data from mitochondrial DNA (mtDNA), the Y chromosome, and two loci on the X chromosome in samples of 25-50 individuals from each of 10 human populations. Application of a coalescent-based Markov chain Monte Carlo technique allows simultaneous inference of divergence times, rates of gene flow, as well as changes in effective population size. Results from comparisons between sub-Saharan African and Eurasian populations estimate that 1500 individuals founded the ancestral Eurasian population ~40 thousand years ago (KYA). Furthermore, these small Eurasian founding populations appear to have grown much more dramatically than either African or Oceanian populations. Analyses of sub-Saharan African populations provide little evidence for a history of population bottlenecks and suggest that they began diverging from one another upward of 50 KYA. We surmise that ancestral African populations had already been geographically structured prior to the founding of ancestral Eurasian populations. African populations are shown to experience low levels of mitochondrial DNA gene flow, but high levels of Y chromosome gene flow. In particular, Y chromosome gene flow appears to be asymmetric, i.e., from the Bantu-speaking population into other African populations. Conversely, mitochondrial gene flow is more extensive between non-African populations, but appears to be absent between European and Asian populations.
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Oceanian populations? What population are they talking about? The quote makes it sound like there was an independent colonization of Oceana from Africa.
The quote makes it sound like there was an independent colonization of Oceana from Africa.
there is the model of the quick beachcomber southern route out of africa. the aboriginals (or whoever they were) were in oz almost immediately after the out of africa event. the same probably applies to the solomon islands.
What Razib said. That was Cavalli-Sforza's surmise from the data.
Michael H. Hart, in Understanding Human History, deduces that proto Austronesians, whom he calls sigmas (for southern out of Africans), split off from the rest of out of Africans either in NE Africa or SW Asia about 60kya. They then followed a shellfish gathering route along the N Indian ocean through India to SE Asia and then Australia, during the last ice age at a time when sea levels were much lower and the coastal route was probably much shorter than it is now.
He also thinks this proto Austronesian group were the first HSS (post archaic) human inhabitants of India - though they were later largely swamped genetically on the subcontinent by Dravidian and other Caucasian agriculturalists, though with some negrito and other survivals. One branch became the Southern Chinese and after changing there for quite a while became the Taiwanese, and Philippines primary populations (with negrito and other earlier versions of pro austronesians as survivals. From there they became Malays and Polynesians, again with earlier austronesian survivals as negritos and mixtures in Malaysia, Borneo and elsewhere. The other main branch populated Papuan New Guinea, Australia and mixed with Polynesias in varying degrees in Melanesia. In historic times the S. Chinese received a substantial northern China Han (NE Asian aka Mongoloid) admixture, though not a swamping one in most places.
i do believe there were later genetic inputs. don't know how much though.
Razib -
Have you come across any web sites which report ancient human population sizes by continent going from the late Pleistocene (emergence of fully modern man and the beginnings of out of Africa) i.e. 100 or 60kya to the present, or at least to say 1 AD - since there are quite a number of easily found places that do a decent job of population sizes by world regions after that? I've tried googling for it several times but never found anything very good in one or even several places.
It's clear that quite a bit of information or at least guesstimates is out there, but I haven't found a good summary. Maps and graphics would be best, natch.
the book the real eve tries. stephen oppenheimer is the author.
Are there any Australian DNA databases?
It would be very interesting to do an acceleration analysis on it.
:-)
Thanks Razib. Order that book.