August 22, 2006

Reconstructing human origins in the genomic era

From the paper:
If the AMH genome contains any degree of dual ancestry (that is, archaic and modern) the single origin model must be rejected. Although most of the AMH genome might descend from a single African population, if further studies confirm a non-negligible contribution of archaic genetic material to the AMH genome, it would imply that the evolutionary lineage leading to AMH did not evolve reproductive isolation from other archaic hominin subpopulations and, therefore, cannot be considered a distinct biological species. Full resolution of this question awaits systematic resequencing surveys of many independent regions of the genome that are far from functional regions (that is, to avoid the possible confounding effects of natural selection). Future analyses of such data could help to resolve whether admixture, if it occurred, was before (low-migration model) or after (isolation and admixture model) the emergence of the AMH phenotype. For this purpose, additional summaries of the DNA resequencing data should be evaluated for their power to distinguish among the predictions of these models.
Nature Reviews Genetics 7, 669-680 (September 2006) | doi:10.1038/nrg1941

Reconstructing human origins in the genomic era

Daniel Garrigan and Michael F. Hammer


Analyses of recently acquired genomic sequence data are leading to important insights into the early evolution of anatomically modern humans, as well as into the more recent demographic processes that accompanied the global radiation of Homo sapiens. Some of the new results contradict early, but still influential, conclusions that were based on analyses of gene trees from mitochondrial DNA and Y-chromosome sequences. In this review, we discuss the different genetic and statistical methods that are available for studying human population history, and identify the most plausible models of human evolution that can accommodate the contrasting patterns observed at different loci throughout the genome.


No comments: