During a wave of expansion that began 4,000 to 5,000 years ago, Bantu-speaking populations – today some 310 million people – gradually left their original homeland of West-Central Africa and traveled to the eastern and southern regions of the continent. Using data from a vast genomic analysis of more than 2,000 samples taken from individuals in 57 populations throughout Sub-Saharan Africa, scientists from the Institut Pasteur and the CNRS, together with a broad international consortium, have retraced the migratory routes of these populations, previously a source of debate. Their research reveals that the admixture that occurred as a result of successive encounters with local populations enabled the Bantus to acquire genetic mutations that helped them adapt to their new environments. Finally, by analyzing the genomes of more than 5,000 African-Americans, the scientists have identified the genetic origins of African populations deported as slaves, and confirmed that the Bight of Benin and West-Central Africa were the main ports used for the slave trade to North America. This research was published on May 5 in the journal Science.
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Some 4,000 to 5,000 years ago, the emergence of farming marked a major turning point in African history. Mastering this new skill enabled Bantu speakers, previously hunter-gatherers living in the region between Cameroon and Nigeria, to gradually leave their homeland and spread to new areas. This was the start of a millennia-long journey that resulted in these populations settling throughout Sub-Saharan Africa.
Yet question marks have always remained as to the exact migratory route taken by these peoples: while a first theory known as "early split" claimed that the Bantu populations immediately divided into two groups on leaving their homeland, one heading east and one south, the "late split" theory suggests that Bantu speakers actually began by traversing the equatorial forest (today part of Gabon), before dividing into two migration waves, one continuing south and the other to East Africa.
Using genomic data from 2,000 individuals from 57 populations throughout Sub-Saharan Africa, a research team from the Institut Pasteur and the CNRS,[1] led by CNRS scientists Etienne Patin and Lluis Quintana-Murci in close collaboration with several African,[2] European[3] and American[4] institutions, have now shed new light on the question. The scientists' research revealed that populations of Bantu speakers from eastern and southern Africa are genetically more similar to populations based south of the equatorial forest than those to the north. These data therefore clearly support the "late split" theory, suggesting that the Bantu first crossed the equatorial forest before branching off into two groups following migratory routes towards eastern and southern Sub-Saharan Africa, where they came into contact with autochtonous populations inhabiting these regions.
