Cultural Evolution of Central African hunter-gatherers reflects a deep history of interconnectivity

Central African hunter-gatherers (CAHGs) are widely seen as isolated populations displaced into the forest by the expansion of Bantu-speaking farmers. By contrast, recent studies revealed various genetic signs of long-term adaptation of CAHGs to forest environments and independence from Bantu demography. It remains unclear whether cultural diversity among CAHGs is better explained by long-term cultural evolution preceding agriculture, or by recent borrowing from neighbouring farmers. We compiled cultural data on musical instruments, foraging tools, and specialised vocabulary as well as genome-wide SNP data from 10 CAHG populations. Our analyses revealed evidence of genetic and cultural large-scale interconnectivity among CAHGs, both before and after the Bantu expansion. By decomposing genomic segments into sets with distinct ancestry depths, we demonstrate that the distribution of hunter-gatherer musical instruments correlates with the oldest genomic segments in our sample. Music-related words are also widely shared between Western and Eastern groups and most likely precede the recent borrowing of Bantu languages. Subsistence tools result from long-term adaptation to locally differentiated ecologies and are less frequently exchanged over long distances. Our results provide evidence that CAHG culture is the outcome of a deep history of long-range interconnectivity and occupation of forest environments in the Congo Basin. We conclude that CAHGs should no longer be seen as encapsulated groups recently marginalised into the forest, but as populations with a central role in our understanding of modern human origins.