About 350 million people across Africa speak one or more than one of the 500 Bantu languages. In a new study published in Nature, scientists at the University of Tartu used spatial genetic modelling to test key hypotheses about the expansion of Bantu-speaking populations across the African continent, including routes, timing, and contacts between populations.
The research shed light on Bantu-speaking populations' demographic history, genetic diversity, and the intricate dynamics that shaped the linguistic, biological, and cultural landscape of the continent.
It has shown that genetic diversity among Bantu-speaking populations gradually declines with distance from western Africa, with current-day Zambia and the Democratic Republic of Congo identified as crucial crossroads of interaction between different routes of expansion. "Our spatial modelling and interdisciplinary approaches support a serial founder migration model, emphasising the demographic significance of the expansion of these populations," says Cesar Fortes-Lima, a population geneticist at Uppsala University (Sweden) and leading author of this study.
It is thanks to the unique efforts within the project to capture the extensive genetic, linguistic and cultural variation in these populations across the entire sub-Saharan Africa, coupled with advanced population genetic modelling and analyses, that we were able to unite evidence from multiple fields of science to answer long-standing questions about this complex process.
Associate Professor Anders Eriksson, an evolutionary biologist at the University of Tartu who led the spatially explicit modelling in the study, emphasises, "It is thanks to the unique efforts within the project to capture the extensive genetic, linguistic and cultural variation in these populations across the entire sub-Saharan Africa, coupled with advanced population genetic modelling and analyses, that we were able to unite evidence from multiple fields of science to answer long-standing questions about this complex process."
The expansion of people speaking Bantu languages is considered one of the most dramatic demographic events in Late Holocene Africa, which began 6,000 to 4,000 years ago in western Africa. This ground-breaking study generated and analysed a comprehensive dataset, including genomic data of modern-day populations from 1,763 participants across 14 African countries and 12 ancient individuals from previously unsampled regions in Africa, providing new insights into this large human expansion.
The novel findings of this study challenge previous models of the expansion of Bantu-speaking populations through single disciplinary studies and emphasise the need for a comprehensive interdisciplinary approach in future studies to understand further how their demographic history influenced their linguistic evolution. The implications of this research are, therefore, far-reaching, touching on historical linguistics, anthropology, population genetics, and biomedical research focused on human genetic diversity in African and African-descendant populations.
The full research study can be accessed in Nature.