more on human diversity

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Am J Hum Genet. 2003 May;72(5):1171-86. Epub 2003 Apr 10.

 

Features of evolution and expansion of modern humans, inferred from

genomewide microsatellite markers.

 

Zhivotovsky LA, Rosenberg NA, Feldman MW.

 

Vavilov Institute of General Genetics, Russian Academy of Sciences, Moscow,

Russia.

 

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 (approximately 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.