Autosomal resequence data reveal Late Stone Age signals of population expansion in sub-Saharan African foraging and farming populations.
BACKGROUND
A major unanswered question in the evolution of Homo sapiens is when anatomically modern human populations began to expand: was demographic growth associated with the invention of particular technologies or behavioral innovations by hunter-gatherers in the Late Pleistocene, or with the acquisition of farming in the Neolithic?


RESULTS
We investigate the timing of human population expansion by performing a multilocus analysis of > or = 20 unlinked autosomal noncoding regions, each consisting of approximately 6 kilobases, resequenced in approximately 184 individuals from 7 human populations. We test the hypothesis that the autosomal polymorphism data fit a simple two-phase growth model, and when the hypothesis is not rejected, we fit parameters of this model to our data using approximate Bayesian computation.


CONCLUSIONS
The data from the three surveyed non-African populations (French Basque, Chinese Han, and Melanesians) are inconsistent with the simple growth model, presumably because they reflect more complex demographic histories. In contrast, data from all four sub-Saharan African populations fit the two-phase growth model, and a range of onset times and growth rates is inferred for each population. Interestingly, both hunter-gatherers (San and Biaka) and food-producers (Mandenka and Yorubans) best fit models with population growth beginning in the Late Pleistocene. Moreover, our hunter-gatherer populations show a tendency towards slightly older and stronger growth (approximately 41 thousand years ago, approximately 13-fold) than our food-producing populations (approximately 31 thousand years ago, approximately 7-fold). These dates are concurrent with the appearance of the Late Stone Age in Africa, supporting the hypothesis that population growth played a significant role in the evolution of Late Pleistocene human cultures.
Cox
Murray P
MP
ARL Division of Biotechnology, University of Arizona, Tucson, Arizona, United States of America.
Morales
David A
DA
Woerner
August E
AE
Sozanski
Jesse
J
Wall
Jeffrey D
JD
Hammer
Michael F
MF
D017954:Africa South of the Sahara; D000383:Agriculture; D001106:Archaeology; D006801:Humans; D011110:Polymorphism, Genetic; D011158:Population Growth