Genetics and Demographic History of the B antu

Abstract

Peoples speaking languages of the Bantu family are widespread in sub‐Saharan Africa, from the equatorial rainforest to the Cape of Good Hope. Their present‐day distribution is the result of a remarkable expansion, which started about 4000–5000 years ago in the borderland between Cameroon and Nigeria. The genetic distances among Bantu‐speaking populations are significantly lower than those between the Bantu and other ethnolinguistic groups from Africa, suggesting an actual movement of people, rather than cultural diffusion. However, this genetic homogeneity places a challenge to the reconstruction of their actual routes of dispersal, with existing hypotheses being mainly based on data from linguistics and archaeology. While the indigenous populations they encountered did not provide a major contribution to the Bantu gene pool at large, admixture studies reveal different patterns of social interaction, which range from Bantu dominance in the rainforest to a more levelled exchange in southern Africa. Key Concepts Most speakers of modern‐day Bantu languages share a distinctive genetic component. The spread of the Bantu languages corresponds to a migratory movement, rather than to cultural diffusion. The Bantu migrations correlate with the appearance of technological innovations and new subsistence strategies in western Central Africa. The range of sampled populations and the resolution of the genetic analyses need to be increased to further explore the genetic relationships among different Bantu groups and infer the dispersal models that best explain them. The best documented cases of admixture between Bantu and non‐Bantu populations are provided by studies that were undertaken in the Central African rainforest and the southern African Kalahari basin.

Matriclans shape populations: Insights from the Angolan Namib Desert into the maternal genetic history of southern Africa

“…For the time of the oldest divergence event (T3; Supporting Information Table S9), we used a flat prior ranging from 14 to 224 kya that contains and extends beyond the range of estimates reported for the split between Khoisan and other groups (Gronau, Hubisz, Gulko, Danko, & Siepel, ; Schlebusch et al, ; Veeramah et al, ). Irrespective of the model, the prior ranges of the two subsequent divergent events (T1 and T2) were allowed to reach 14 kya (the minimum value of T3), which predates the beginning of the Bantu expansion 4–5 kya by a large margin (Rocha and Fehn, ) (Supporting Information Table S9). Since the prior ranges of T1 and T2 overlap, the prior of T1 is not flat.…”

“…This absence of an mtDNA identity is paralleled by recent data on autosomal DNA variation, showing that many Khoe‐Kwadi‐speaking groups are genetically closer to populations occupying the same broad geographical area than they are to each other (Montinaro et al, ; Pickrell et al, ; Uren et al, ). Taken together, these patterns suggest that the spread of Khoe‐Kwadi and its putative pastoral innovations were part of a complex process that cannot be simply modeled by a wave of advance similar to the spread of agriculture in Europe (Pinhasi, Fort, & Ammerman, ), nor by a rapid replacement model, analogous to the Bantu expansions (reviewed in Rocha & Fehn, ; see also Diamond & Bellwood, ). It seems more likely that many southern African groups adopted the Khoe‐Kwadi language (and occasionally pastoralism) with only a small genetic contribution of incoming Khoe‐Kwadi migrants.…”

The role of matrilineality in shaping patterns of Y chromosome and mtDNA sequence variation in southwestern Angola

“…This observation, together with recent genome-wide estimates of 9-22% of eastern African ancestry in other Kx'a and Tuu-speaking groups [36], suggests that eastern African admixture was not restricted to present-day Khoe-Kwadi speakers. Alternatively, it is likely that the dispersal of pastoralism and Khoe-Kwadi languages involved a series of punctuated contacts that led to a wide variety of cultural, genetic and linguistic outcomes, including possible shifts to Khoe-Kwadi by originally Bantu-speaking peoples [37].…”

The role of matrilineality in shaping patterns of Y chromosome and mtDNA sequence variation in southwestern Angola

“…This observation, together with recent genome-wide estimates of 9-22% of eastern African ancestry in other Kx'a and Tuu-speaking groups 35 , suggests that eastern African admixture was not restricted to present-day Khoe-Kwadi speakers. Alternatively, it is likely that the dispersal of pastoralism and Khoe-Kwadi languages involved a series of punctuated contacts that led to a wide variety of cultural, genetic and linguistic outcomes, including possible shifts to Khoe-Kwadi by originally Bantu-speaking peoples 36 .…”