mtDNA Variation in Kung and Kwhe

Swiped from Mathilda's Blog, of course:

Link to Abstract

The mtDNA variation of 74 Khoisan-speaking individuals (Kung and Khwe) from Schmidtsdrift, in the Northern Cape Province of South Africa, was examined by high-resolution RFLP analysis and control region (CR) sequencing. The resulting data were combined with published RFLP haplotype and CR sequence data from sub-Saharan African populations and then were subjected to phylogenetic analysis to deduce the evolutionary relationships among them. More than 77% of the Kung and Khwe mtDNA samples were found to belong to the major mtDNA lineage, macrohaplogroup L* (defined by a HpaI site at nucleotide position 3592), which is prevalent in sub-Saharan African populations. Additional sets of RFLPs subdivided macrohaplogroup L* into two extended haplogroups—L1 and L2—both of which appeared in the Kung and Khwe. Besides revealing the significant substructure of macrohaplogroup L* in African populations, these data showed that the Biaka Pygmies have one of the most ancient RFLP sublineages observed in African mtDNA and, thus, that they could represent one of the oldest human populations. In addition, the Kung exhibited a set of related haplotypes that were positioned closest to the root of the human mtDNA phylogeny, suggesting that they, too, represent one of the most ancient African populations. Comparison of Kung and Khwe CR sequences with those from other African populations confirmed the genetic association of the Kung with other Khoisan-speaking peoples, whereas the Khwe were more closely linked to non–Khoisan-speaking (Bantu) populations. Finally, the overall sequence divergence of 214 African RFLP haplotypes defined in both this and an earlier study was 0.364%, giving an estimated age, for all African mtDNAs, of 125,500–165,500 years before the present, a date that is concordant with all previous estimates derived from mtDNA and other genetic data, for the time of origin of modern humans in Africa.

Quote Mathilda: One Halogroup, L3a, seems closely related to M1 and M, as L3a is the precursor to M.

The Asian mtDNA phylogeny is subdivided into two macrohaplogroups, one of which is M. M is delineated by a DdeI site at np 10394 and an AluI site of np 10397. The only African mtDNA found to have both of these sites is the Senegalese haplotype AF24. This haplotype branches off African subhaplogroup L3a (figs.2 and3), suggesting that haplogroup M mtDNAs might have been derived from this African mtDNA lineage; however, it is also possible that this particular haplotype is present in Africa because of back-migration from Asia.

Since M itself seems absent in Africa, and M1 traces the path of U in North and East Africa pretty closely, it’s now pretty much a done deal that M1 arrived in North Africa from West Asia. The real mystery is the lack of L3 and M in India, but the Toba eruption could easily have caused a wipe out across India that erased the first immigrants there. I’d like to observe that this L3a seems to have followed the North African population movements that curved southwards down into the West coast of Africa, so I think that its from the back migration may be possible, or at least dating to the expansion from upper Egypt about 24k ago with a origin from the Nile area. - Mathilda