New research sheds light on Bantu-speaking populations’ expansion in Africa

30 November 2023 - Wits University

The study is unique in that it contains genetic data of both living and past (archaeological DNA/aDNA) populations.

The vast Bantu-speaking populations in sub-Saharan Africa probably originated in western Africa before moving to the south and east in consistent waves, suggests a study published in Nature on Wednesday, 29 November 2023.

Genetic analysis of modern and ancient individuals offers new insights into the evolutionary history of Bantu-speaking peoples, whose populations began to expand around 6,000–4,000 years ago in western Africa.

The Bantu linguistic family comprises over 500 distinct languages, spoken by approximately 350 million people across sub-Saharan Africa. The expansion patterns of Bantu-speaking populations are notable for their longitudinal progression, through diverse climates and environments, which is far less common than latitudinal movement across like terrains.

Senior author Professor Carina Schlebusch of Uppsala University, Sweden, and colleagues, collated a genomic dataset of 1,763 modern-day individuals (1,526 Bantu-speaking individuals from 147 populations, and 237 other sub-Saharan African individuals) representing all major branches of the Bantu language family and including 117 populations that have gone unrepresented in previous genetic studies.

Additionally, the DNA of 12 ancient individuals from Late Iron Age sites in present-day Zambia and South Africa (spanning 97–688 years before present) was sequenced to provide insights into the ancient history of the Bantu speaker migration patterns. The group analysed the history and movement of Bantu-speaking populations through a combination of genetic, linguistic and geographic modelling.

Dr Anja Meyer and Professor Maryna Steyn in Wits University’s Human Variation and Identification Research Unit (HVIRU) are co-authors of the study as is Professor Himla Soodyall in the Division of Human Genetics. They were involved in the archaeological/aDNA part of the project specifically.

The genetic data provide evidence that Bantu-speaking populations originated in western Africa and expanded through the Congo rainforest into eastern and southern Africa.

The authors observed a pattern of decreased genetic diversity as distance increases from the populations’ point of origin.

The analyses revealed evidence for mixing between Bantu-speaking populations and local groups, which was also found to decrease with distance from the origin point.

This correlation suggests a relatively constant rate of expansion of Bantu-speaking populations, despite the variety in climate and landscapes into which these populations were migrating.

Present-day Zambia and the Democratic Republic of Congo were identified as key points of interaction for expansion of the Bantu-speaking population.

These results provide a valuable resource for future studies into populations in Africa and may also be a resource for studying genetic variation and health in these populations.