Genetic Chaos

Thursday, October 26, 2006

Population structure and history in East Asia

Archaeological, anatomical, linguistic, and genetic data have suggested that there is an old and significant boundary between the populations of north and south China. We use three human genetic marker systems and one human-carried virus to examine the north/south distinction. We find no support for a major north/south division in these markers; rather, the marker patterns suggest simple isolation by distance.

PDF file

Evidence for Archaic Asian Ancestry on the Human X Chromosome

The human RRM2P4 pseudogene has a pattern of nucleotide polymorphism that is unlike any locus published to date. A gene tree constructed from a 2.4-kb fragment of the RRM2P4 locus sequenced in a sample of 41 worldwide humans clearly roots in East Asia and has a most-recent common ancestor approximately 2 Myr before present. The presence of this basal lineage exclusively in Asia results in higher nucleotide diversity among non-Africans than among Africans. A global survey of a single-nucleotide polymorphism that is diagnostic for the basal, Asian lineage in 570 individuals shows that it occurs at frequencies up to 53% in south China, whereas only one of 177 surveyed Africans carries this archaic lineage. We suggest that this ancient lineage is a remnant of introgressive hybridization between expanding anatomically modern humans emerging from Africa and archaic populations in Eurasia.

PDF file