The Bantu expansion revisited: a new analysis of Y chromosome variation in Central Western Africa

Abstract

The current distribution of Bantu languages is commonly considered to be a consequence of a relatively recent population expansion (3-5kya) in Central Western Africa. While there is a substantial consensus regarding the centre of origin of Bantu languages (the Benue River Valley, between South East Nigeria and Western Cameroon), the identification of the area from where the population expansion actually started, the relation between the processes leading to the spread of languages and peoples and the relevance of local migratory events remain controversial. In order to shed new light on these aspects, we studied Y chromosome variation in a broad dataset of populations encompassing Nigeria, Cameroon, Gabon and Congo. Our results evidence an evolutionary scenario which is more complex than had been previously thought, pointing to a marked differentiation of Cameroonian populations from the rest of the dataset. In fact, in contrast with the current view of Bantu speakers as a homogeneous group of populations, we observed an unexpectedly high level of interpopulation genetic heterogeneity and highlighted previously undetected diversity for lineages associated with the diffusion of Bantu languages (E1b1a (M2) sub-branches). We also detected substantial differences in local demographic histories, which concord with the hypotheses regarding an early diffusion of Bantu languages into the forest area and a subsequent demographic expansion and migration towards eastern and western Africa.

Evidence from Y-chromosome analysis for a late exclusively eastern expansion of the Bantu-speaking people

“…As a consequence, this study makes an important contribution to filling the gap. Pakendorf et al 7 identify and provide evidence of greater complexity in the process of the EBSP as suggested by Alves et al 33 and Montano et al 34 …”

“…Recently, Alves et al 33 analysing a battery of 14 DIPSTRs (ie, deletion/ insertion polymorphisms tightly linked to STRs) in 19 Bantuspeaking groups from Mozambique and Angola concluded that it is becoming increasingly difficult to accept models, suggesting an early split between eastern and western Bantu-speaking populations, whereas Montano et al 34 analysing NRY UEPs and STRs in groups from Nigeria, Cameroon, Gabon and Congo concluded that the evolutionary scenario is more complex than previously thought. Our analysis of NRY from groups over a wide geographic area is consistent with both these conclusions.…”

Palenque de San Basilio in Colombia: genetic data support an oral history of a paternal ancestry in Congo

“…Similar to the approach taken by Di Giacomo et al [50], we compared the distribution of NRY variation within E-sY81 (E1b1a; the signature haplogroup of EBSP [19,35,51,52]), a clade that was present in all population samples including Palenque, and observed only in men of RAD. F ST between the Palenque and the other groups, based on the frequencies of the E-sY81 component haplogroups, revealed only two groups with a nonsignificant F ST (Chewa and Yombe) with the Yombe-Palenque F ST , 0.001 (electronic supplementary material, table S6).…”

Unraveling the Population History of Indian Siddis

“…Several studies have suggested that multiple migratory routes of Bantu populations seemingly converged, overlapped, and split during distinct periods of time leading to the spread of Bantu genomes and languages to a great majority in subequatorial Africa (Ansari Pour et al 2013; de Filippo et al 2011, 2012; Montano et al 2011; Plaza et al 2004). Given the extensive and intricate nature of population expansions that spanned across Africa the precise geographic deduction of the ancestral origin of Siddi genomes had so far remained elusive (Narang et al 2011).…”