Here is a paper (actually, an abstract) from the American Journal of Human Genetics that I had overlooked, and that may also have been missed by other people. I haven’t had the chance, yet, to read the paper, but I have, nonetheless taken the liberty to append a few comments based on the abstract. I realize that it is a bit risky, but . . .
Zhivotovsky, Lev A., Noah A. Rosenberg, and Marcus W. Feldman. 2003. Features of Evolution and Expansion of Modern Humans, Inferred from Genomewide Microsatellite Markers. American Journal of Human Genetics 72:1171-1186.
Electronically published April 10, 2003.
We study data on variation in 52 worldwide populations at 377 autosomal short tandem repeat loci, to infer a demographic history of human populations. Variation at di-, tri-, and tetranucleotide repeat loci is distributed differently, although each class of markers exhibits a decrease of within-population genetic variation in the following order: sub-Saharan Africa, Eurasia, East Asia, Oceania, and America. There is a similar decrease in the frequency of private alleles. With multidimensional scaling, populations belonging to the same major geographic region cluster together, and some regions permit a finer resolution of populations. When a stepwise mutation model is used, a population tree based on TD estimates of divergence time suggests that the branches leading to the present sub-Saharan African populations of hunter-gatherers were the first to diverge from a common ancestral population (ca.71-142 thousand years ago). The branches corresponding to sub-Saharan African farming populations and those that left Africa diverge next, with subsequent splits of branches for Eurasia, Oceania, East Asia, and America. African hunter-gatherer populations and populations of Oceania and America exhibit no statistically significant signature of growth. The features of population subdivision and growth are discussed in the context of the ancient expansion of modern humans.
© 2003 by The American Society of Human Genetics. All rights reserved.
I suspect that the “dating” of the events being discussed here (ca.71-142 thousand years ago) is likely to be an example, a reflection of some sort of a “chronological mantra” that a number of molecular bio/palaeoanthropologists have been imprinted with and that has introduced in many of the present debates regarding the Late Pleistocene evolution of humans, a strange and rather annoying “circularity”. It spans approximately 71,000 years of evolutionary time. This includes part of a Glacial (OIS-6), the Last Interglacial (OIS-5e), and the full range of the climatic events that precede the Lower Pleniglacial (OIS-5d-5a). Surely, it is certainly not a paragon of precision -- as is true for many other papers, and adds very little to our ability to understand (from a prehistoric/chronometric point-of-view) more than the fuzzy genetic signatures/components of historical/evolutionary human biogeography.
I am really looking forward to the day when the writing of well integrated, truly interdisciplinary papers, dealing with such a broad range of issues will become a fad.
Jacques Cinq-Mars
