Project description:<p>These data were used as part of a study to characterize genomic diversity in Africa, population substructure, and evolutionary history.</p>
Project description:The history of click-speaking Khoe-San, and African populations in general, remains poorly understood. We genotyped ~2.3 million SNPs in 220 southern Africans and found that the Khoe-San diverged from other populations at least 100,000 years ago, but structure within the Khoe-San dated back to about 35,000 years ago. Genetic variation in various sub-Saharan populations did not localize the origin of modern humans to a single geographic region within Africa, instead, it indicated a history of admixture and stratification. We found evidence of adaptation targeting muscle function and immune response, potential adaptive introgression of UV-light protection, and selection predating modern human diversification involving skeletal and neurological development. These new findings illustrate the importance of African genomic diversity in understanding human evolutionary history .220 samples were analysed with the Illumina HumanOmni2.5-Quad BeadChip and are described herein.
Project description:The transatlantic slave trade (TAST) was the largest forced migration in world history. However, the origins of the enslaved Africans and their admixture dynamics remain unclear. To investigate the demographic history of African-descendant Marron populations, we generated genome-wide SNP data (4.3 million markers) from 107 individuals from three African-descendant populations in South America, as well as 124 individuals from six west African populations to complement underrepresented African data sets. Our study sheds additional light on the demographic consequences of the TAST and illustrates how genetic data can complement historical sources.
Project description:The Sahel/Savannah belt harbours diverse populations with different demographic histories and different subsistence patterns. However, populations from this large African region are notably under-represented in genomic research. To investigate the population structure and adaptation history of populations from the Sahel/Savannah space, we generated dense genome-wide genotype data of 327 individuals—comprising 14 ethnolinguistic groups, including ten previously unsampled populations. DNA samples were genotyped on the Illumina H3Africa Consortium Array (BeadChip type: H3Africa_2017_20021485_A2; designed for SNP-genotyping of 2,267,346 SNPs) at the SNP&SEQ Technology Platform, NGI/SciLifeLab Genomics (Sweden). Reference: Demographic and Selection Histories of Populations Across the Sahel/Savannah Belt. Fortes-Lima C, Tříska P, Čížková M, Podgorná E, Diallo MY, Schlebusch CM, Černý V. Molecular Biology and Evolution 2022 39(10):msac209. doi: 10.1093/molbev/msac209. PMID: 36173804 .
Project description:The distribution of deleterious genetic variation across human populations is a key issue in evolutionary biology and medical genetics. However, the impact of different modes of subsistence on recent changes in population size, patterns of gene flow, and deleterious mutational load remains unclear. Here, we report high-coverage exomes from various populations of rainforest hunter-gatherers and farmers from central Africa. We find that the recent demographic histories of hunter-gatherers and farmers differed considerably, with population collapses for hunter-gatherers and expansions for farmers, accompanied by increased gene flow. We show that purifying selection against newly arising deleterious alleles is of similar efficiency across African populations, in contrast with Europeans where we detect weaker purifying selection. Furthermore, the per-individual mutation load of rainforest hunter-gatherers is similar to that of farmers, under both additive and recessive models. Our results indicate that differences in the cultural practices and demographic regimes of African populations have not resulted in large differences in mutational burden, and highlight the beneficial role of gene flow in reshaping the distribution of deleterious genetic variation across human populations.