Evidence for Archaic Asian Ancestry on the Human X Chromosome
Daniel Garrigan1, Zahra Mobasher1, Tesa Severson1, Jason A. Wilder1
and Michael F. Hammer1,2 October 13, 2004
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 ~2 million years before the present. The presence of this basal lineage exclusively in Asia results in higher nucleotide diversity among non-Africans than 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, while 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.
Recently Hammer et al. (2004) analyzed global human nucleotide variation at 15 X linked loci, one of which stands out as unique in its pattern of polymorphism. In a global sample of 41 individuals, sequence variation at the ribonucleotide reductase M2 subunit pseudogene 4 (RRM2P4) is partitioned into two divergent, basal lineages. Both of these lineages are found in Asia, while only one is found in sub-Saharan Africa (figure 1B). The two lineages differ by five fixed mutations, leading to an estimate for the time to a most recent common ancestor (TMRCA) that is ~2 million years before the present.
There are quite a few estimated dates for genes that really cast a shadow over the OOA theory, one red hair mutation in Europeans had a date of 80,000 years, which would stick it into a Neanderthal time frame. Any one curious, look up the ‘out of Africa deception’ for a list of them.