Admixture into and within sub-Saharan Africa.

George Bj Busby,Chris Ca Spencer,Quang Si Le,Tobias Apinjoh,Ogobara Doumba,Dominic P Kwiatkowski,Muminatou Jallow,Valentina D Mangano,Lucas N Amenga-Etego,Kirk A Rockett,Gavin Band,Carolyne M Ndila,Anthony Enimil,Vysaul Nyirongo,Malaria Genomic Epidemiology Network ,Edith Bougama,Alphaxard Manjurano

doi:10.7554/elife.15266

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.

Highlights

Advances in DNA analysis technology and the drive to understand the genetic basis of human phenotypes has led to a rapid growth in the amount of genomic data that is available for analysis
For example we write “Eurasian ancestry in East African Niger-Congo speakers”, where the more precise definition would be “ancestry originating from groups currently living in Eurasia in groups currently living in East Africa that speak Niger-Congo languages” (Pickrell et al, 2014)
As in other regions of the world (Novembre et al, 2008; Behar et al, 2010), the leading principal components show that genetic relationships are broadly defined by geographical and ethno-linguistic similarity (Figure 1B,C)

Summary

Introduction

Advances in DNA analysis technology and the drive to understand the genetic basis of human phenotypes has led to a rapid growth in the amount of genomic data that is available for analysis. Several consortia are beginning to focus on understanding the genetic basis of infectious and non-communicable disease in Africa. Genomics and evolutionary biology eLife digest Our genomes contain a record of historical events. This is because when groups of people are separated for generations, the DNA sequence in the two groups’ genomes will change in different ways. Looking at the differences in the genomes of people from the same population can help researchers to understand and reconstruct the historical interactions that brought their ancestors together. The mixing of two populations that were previously separate is known as admixture

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Results

Conclusion