Gene Expression

A little bit of the Others in Us

Dienekes has reposted some of the abstracts from the meeting of the American Association of Physical Anthropologists. This one caught my eye, Genetic analyses reveal a history of serial founder effects, admixture between long separated founding populations in Oceania, and interbreeding with archaic humans:

Genetic anthropologists continue to debate whether human neutral genetic variation primarily reflects a continuum of demes connected by local gene flow or colonization and serial founder effects. A second unresolved issue concerns the genetic contribution of archaic species to the modern human gene pool. Some studies suggest that this contribution was substantial and that it played an important role in human adaptation. These issues remain unresolved because of inadequacies and biases in datasets, problems in statistical methodology, and the failure to recognize that different evolutionary processes may produce similar outcomes. This study redresses these limitations by analyzing gene identity within and between populations in a dataset comprised of 614 STRs assayed in 1,983 people from 99 widespread populations. Our strategy is to fit hierarchical models to these data and examine residual deviations from the models. Each model involves nesting smaller units such as populations into larger units such as continental regions. It is possible to restate many of these models as either expansions or reductions of each other and thereby identify aspects of population structure that have had a major impact on the overall pattern of diversity. The strong fit of a model estimated using the Neighbor Joining algorithm indicates that human genetic diversity primarily reflects a history of successive founder effects associated with our exodus from Africa, not a continuum of demes connected by gene flow. Residual deviations from the model suggest: 1) the genomes of Oceanic peoples are the product of two independent waves of migration to the region and admixture, and 2) genetic exchange occurred between archaic and modern humans after their initial divergence.

Would be nice if they found a gene which was likely differentiated between archaic and modern alleles, but it doesn’t look like that. But the number of populations seems rather large.

Comments

  1. #1 Ponto
    March 17, 2010

    Maybe I should not speak out of school, but a person on a Human biodiversity Forum, ABF, is running trials using Structure, and some blocks of SNPs derived from forum members. One of his tests using these SNPs, about 750, showed what he called “Paleolithic” Eurasian. I got 1.0% for that, I also got 0.7% for Oceanian. I know those two figures are low and could be dismissed as noise, but my results are higher than the others. On his phylogenetic tree, those two groups are near each other. I am Southern European, quite Mediterranean, and Oceania is quite distant from where I was born and where my ancestry derives.

  2. #2 pconroy
    March 18, 2010

    Ponto,

    Can you link to the relative forum post, as I’d like to join in the fun too!

    TIA

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