Maternal traces of deep common ancestry and asymmetric gene flow between Pygmy hunter–gatherers and Bantu-speaking farmers

Abstract

Two groups of populations with completely different lifestyles-the Pygmy hunter-gatherers and the Bantu-speaking farmers-coexist in Central Africa. We investigated the origins of these two groups and the interactions between them, by analyzing mtDNA variation in 1,404 individuals from 20 farming populations and 9 Pygmy populations from Central Africa, with the aim of shedding light on one of the most fascinating cultural transitions in human evolution (the transition from hunting and gathering to agriculture). Our data indicate that this region was colonized gradually, with an initial L1c-rich ancestral population ultimately giving rise to current-day farmers, who display various L1c clades, and to Pygmies, in whom L1c1a is the only surviving clade. Detailed phylogenetic analysis of complete mtDNA sequences for L1c1a showed this clade to be autochthonous to Central Africa, with its most recent branches shared between farmers and Pygmies. Coalescence analyses revealed that these two groups arose through a complex evolutionary process characterized by (i) initial divergence of the ancestors of contemporary Pygmies from an ancestral Central African population no more than Ϸ70,000 years ago, (ii) a period of isolation between the two groups, accounting for their phenotypic differences, (iii) long-standing asymmetric maternal gene flow from Pygmies to the ancestors of the farming populations, beginning no more than Ϸ40,000 years ago and persisting until a few thousand years ago, and (iv) enrichment of the maternal gene pool of the ancestors of the farming populations by the arrival and/or subsequent demographic expansion of L0a, L2, and L3 carriers.Africa ͉ evolution ͉ human ͉ mtDNA ͉ populations

The impact of agricultural emergence on the genetic history of African rainforest hunter-gatherers and agriculturalists

“…1b,c; Supplementary Figs 2-4). These observations are consistent with the proposed branching model of these populations-based on a limited number of autosomal and uniparentally inherited markers-involving an early divergence of the ancestors of RHG and AGR B50,000-65,000 YBP, followed by a split of RHG ancestors into the Western and Eastern groups B20,000-30,000 YBP 21,[23][24][25]32 .…”

Population Genetic Analysis of the DARC Locus (Duffy) Reveals Adaptation from Standing Variation Associated with Malaria Resistance in Humans

“…The first line of evidence for this scenario is that Baka and Mbuti populations have identical FY Ã O haplotypes in similar proportions as the Bantu populations. This is relevant because Baka and Mbuti are hunter-gatherer populations that diverged a long time ago from Bantu African populations (50-65 kya) as well as from each other (20-30 kya) [47,[65][66][67][68]. Secondly, we observe low levels of admixture between these groups (Bantu admixture in Mbuti: 0-16%, Bantu admixture in Baka: 6.5-9.4%) [69,70].…”

Linking the sub-Saharan and West Eurasian gene pools: maternal and paternal heritage of the Tuareg nomads from the African Sahel

“…We assayed to Genetic diversity of Tuareg nomads L Pereira et al search for haplotype matches in an extensive database of 7211 individuals from all over Africa (Table 2). The most ancient lineages L0a1a and L1c, characteristic of east/southeast Africa 13 and the Pygmies, 39 respectively, were each observed in only one individual. The highly frequent African haplogroup L2, and specifically its dominant clade L2a, is also dominant in Tuareg -it is probable that some branches of L2a were involved in the Bantu expansion towards the African south 13,40 and many matches are observed for these haplotypes all over the continent.…”