Bantu-speaker migration and admixture in southern Africa

Abstract

The presence of Early and Middle Stone Age human remains and associated archaeological artefacts from various sites scattered across southern Africa, suggests this geographic region to be one of the first abodes of anatomically modern humans. Although the presence of hunter-gatherer cultures in this region dates back to deep times, the peopling of southern Africa have largely been reshaped by three major sets of migrations over the last 2000 years. These migrations have led to a confluence of four distinct ancestries (San hunter-gatherer, East African pastoralist, Bantu-speaker farmer and Eurasian) in populations from this region. In this review, we have summarized the recent insights into the refinement of timelines and routes of the migration of Bantu-speaking populations to southern Africa and their admixture with resident southern African Khoe-San populations. We highlight two recent studies hinting at the emergence of fine-scale population structure within some South-Eastern Bantu-speaker groups. We also accentuate whole genome sequencing studies (current and ancient) that have both enhanced our understanding of the peopling of southern Africa and demonstrated a huge potential for novel variant discovery in populations from this region. Finally, we identify some of the major gaps and inconsistencies in our understanding and emphasize the importance of more systematic studies of southern African populations from diverse ethnolinguistic groups and geographic locations.

Modern human expansion from (southern?) Africa: Origin, non-African ancestry, and linearity

“…Regarding indicators of the expansion from Africa, most of the types of peak points are in southern Africa (four out of five), which generally supports southern Africa being the origin (Figure 6, with two of these peak points themselves being a centroid or an average). Indeed, a centroid of the peak points suggests that southern Africa is the most probable origin of the expansion (Figure 6), in the context of the peak points generally clustering in the southern African region (like in Choudhury et al 2021, Angola, Malawi, and Zambia were regarded as part of southern Africa in the present research).…”

Divergence and contact in Southern Bantu language and population history

“…However, with the currently available data, it is not possible to distinguish the number of migration events that brought Bantu-speaking communities into southern Africa. Larger and more detailed data sets may answer this question in the future (Choudhury et al, 2021). Shona-speaking populations in particular are not well represented in the currently available genetic studies, not even in Semo et al ( 2020), which does contain some Mozambican Shona samples.…”

“…This admixture took place within the last 1,300 years (Sengupta et al, 2021;Semo et al, 2020). There are indications that more northern populations, speaking languages of the Venda, Tsonga, and Copi groups, show earlier admixture than populations living further south, speaking languages of the Sotho and Nguni groups (Sengupta et al, 2021;Semo et al, 2020). However, these early admixture dates may also be due to a limitation in dating techniques, as these populations also show very low degrees of admixture (Choudhury et al, 2021).…”

“…Genetic studies provide further valuable insights into the history of interactions between Southern Bantu-speaking groups and their Khoisan-speaking neighbors. Southern Bantu-speaking populations show varying degrees of Khoisan admixture (Choudhury et al, 2021), which are low in populations speaking languages that belong to the Tsonga, Copi, Venda, and Shona clusters, but much higher in populations speaking languages of the Sotho and Nguni clusters (see Table 8). This admixture took place within the last 1,300 years (Sengupta et al, 2021;Semo et al, 2020).…”

“…Southern Bantu-speaking populations show varying degrees of Khoisan admixture (Choudhury et al, 2021), which are low in populations speaking languages that belong to the Tsonga, Copi, Venda, and Shona clusters, but much higher in populations speaking languages of the Sotho and Nguni clusters (see Table 8). This admixture took place within the last 1,300 years (Sengupta et al, 2021;Semo et al, 2020). There are indications that more northern populations, speaking languages of the Venda, Tsonga, and Copi groups, show earlier admixture than populations living further south, speaking languages of the Sotho and Nguni groups (Sengupta et al, 2021;Semo et al, 2020).…”