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

The current distribution of Bantu languages is commonly considered to be a consequence of a relatively recent population expansion (3-5 kya) 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 inter-population 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.班图语（Bantu languages）的当前分布格局，通常被认为是西非中部地区一次相对较近的人口扩张（距今3000至5000年）所导致的结果。尽管学界已就班图语的起源中心——位于尼日利亚东南部与喀麦隆西部之间的贝努埃河谷（Benue River Valley）——达成广泛共识，但关于此次人口扩张的实际起始区域、推动语言与族群扩散的进程间的关联，以及区域性迁徙事件的相关意义，仍存在诸多争议。为厘清上述议题并提供新的研究视角，我们针对涵盖尼日利亚、喀麦隆、加蓬与刚果的多个人群构建了大规模数据集，并对其中的Y染色体变异（Y chromosome variation）情况展开了研究。我们的研究结果揭示出一套比此前认知更为复杂的演化图景，表明喀麦隆人群与该数据集内其余人群存在显著的遗传分化。事实上，与当前将班图语使用者视为同质化人群群体的主流观点相悖，我们观测到了意料之外的高水平人群间遗传异质性，并揭示出此前未被发现的、与班图语扩散相关的遗传谱系（E1b1a（M2）亚分支）多样性。我们还发现不同区域的人口历史存在显著差异，这与相关假说相契合：班图语早期先扩散至雨林区域，随后发生人口扩张并向非洲东部与西部迁徙。