Researchers from the University of Oxford have revealed that the genetic ancestries of many of sub-Saharan Africa's populations are the result of historical DNA mixing events within the last 4000 years.
     Lead author George Busby, Statistical Geneticist at the Wellcome Trust Centre for Human Genetics, says: "As Africa has few written records of its history, it is somewhat unknown what important movements of people generated the populations in the continent today. Looking at and comparing the differences in the genomes of people alive today can help us better understand and reconstruct the historical interactions that brought their ancestors together."
     The team used DNA analysis to characterise the structure of genetic diversity and gene flow - the transfer of genes between different populations - in a collection of 48 sub-Saharan African groups. They discovered that most sub-Saharan populations share ancestry with groups from outside their current geographic region as a result of gene flow within the last 4000 years.
     Dr Busby explains: "Our research provides further genetic evidence that the spread of Bantu languages and agricultural technology from Central West Africa, known as the Bantu expansion, was likely to be accompanied by people who moved from Cameroon to the south and east within the last 2500 years. Additionally, we revealed that coastal populations in western, eastern, and southern Africa experienced small influxes of Eurasian genes as a result of different events over the last 3000 years. These findings show that groups from similar parts of Africa experienced admixture events at similar times and involving similar sources, suggesting that genetic variation in these areas of the continent has been shaped by shared historical events. It is also clear that our ancestors have always moved about and traces of these migrations are left in the DNA of people alive today."

Edited from PhysOrg (21 June 2016)