Admixture into and within sub-Saharan Africa

TLDR

Similarity between two individuals in the combination of genetic markers along their chromosomes indicates shared ancestry and can be used to identify historical connections between different population groups due to admixture. The study aims to characterise the structure of genetic diversity and gene‑flow in 48 sub‑Saharan African groups. The authors employ a genome‑wide, haplotype‑based analysis to achieve this. Coastal populations received Eurasian haplotypes in the last 7,000 years, Eastern and Southern Niger‑Congo groups share ancestry with Central West Africans from recent expansions, and most sub‑Saharan populations have ancestry from outside their region via gene‑flow in the last 4,000 years, offering insight into haplotype sharing and recent allele movement relevant to genetic epidemiology.

Abstract

Similarity between two individuals in the combination of genetic markers along their chromosomes indicates shared ancestry and can be used to identify historical connections between different population groups due to admixture. We use a genome-wide, haplotype-based, analysis to characterise the structure of genetic diversity and gene-flow in a collection of 48 sub-Saharan African groups. We show that coastal populations experienced an influx of Eurasian haplotypes over the last 7000 years, and that Eastern and Southern Niger-Congo speaking groups share ancestry with Central West Africans as a result of recent population expansions. In fact, most sub-Saharan populations share ancestry with groups from outside of their current geographic region as a result of gene-flow within the last 4000 years. Our in-depth analysis provides insight into haplotype sharing across different ethno-linguistic groups and the recent movement of alleles into new environments, both of which are relevant to studies of genetic epidemiology.