As I browsed Dienekes earlier today, I was unexpectedly transported back to the ethnographic survey (Johnston et al., 1913) referenced by my last post. In a newly-released study, Sikora et al. (2010) employ 2841 SNPs to analyze population structure in 12 sub-Saharan populations, including one from previously-unsampled Mozambique. Figure 3, a STRUCTURE diagram, is shown below:
Most intriguing to me were the “hunter-gatherer” component which emerges at K=3 and the dissimilarity of the Mozambique samples from their linguistic relatives. As the authors comment:
The southeastern Bantu from Mozambique are remarkably differentiated from the western Niger-Congo speaking populations, such as the Mandenka and the Yoruba, and also differentiated from geographically closer Eastern Bantu samples, such as Luhya. These results suggest that the Bantu expansion of languages, which started ~5000 years ago at the present day border region of Nigeria and Cameroon, and was probably related to the spread of agriculture and the emergence of iron technology, was not a demographic homogeneous migration with population replacement in the southernmost part of the continent, but acquired more divergence, likely because of the integration of pre-Bantu people. [...] the singularity of the southeastern population of Mozambique (poorly related to present Khoisan) could be attributed to a complete assimilation of ancient genetically differentiated populations (presently unknown) by Bantu speakers in southeastern Africa, without leaving any pre-Bantu population in the area to compare with.