Abstract With the largest genomic dataset to date of Bantu-speaking populations, including newly generated data of modern-day and ancient DNA from previously unsampled regions in Africa, we shed fresh light on the expansion of peoples speaking Bantu languages that started ∼4000 years ago in western Africa. We have genotyped 1,740 participants, including 1,487 Bantu speakers from 143 populations across 14 African countries, and generated whole-genome sequences from 12 Late Iron Age individuals. Our results show that Bantu speakers received significant gene-flow from local groups in regions they expanded into. We show for the first time that genetic diversity amongst Bantu-speaking populations declines with distance from western Africa, with current-day Zambia and the DRC as possible crossroads of interaction. Using spatially explicit methods and correlating genetic, linguistic and geographical data, we provide cross-disciplinary support for a serial founder migration model. Finally, we discuss the utility of our dataset as an exhaustive modern-day African comparative dataset for ancient DNA studies. These new findings and data will be important to a wide range of disciplines from science and humanities as well as to the medical sector studying human genetic variation and health in African and African-descendant populations. One-sentence summary A comprehensive genetic analysis of the expansion of people speaking Bantu languages reveals a complex history of serial founder events, variable levels of contact with local groups, and spread-over-spread events.

The genetic legacy of the expansion of Bantu-speaking peoples in Africa