The first humans left Africa some 200,000 years ago, dispersing to populate the rest of the world. But this was not a one-way trip: some people came back. Scientists say that they have traced a reverse migration that, in two steps, carried genes from the rest of the world back to southern Africa, long before European colonizers arrived.
The findings are part of a flurry of research enabled by better tools to survey African genomes. For the first time, population geneticists can examine the complex history of human migration in Africa effectively, a field long dominated by the analysis of bones, artefacts and languages.
“Up until now this was mostly done based on linguistics and archaeology, and now we can use genetics to test ideas,” says Carina Schlebusch, a geneticist at Uppsala University in Sweden. “It’s a really exciting time for African genetics.”
Genetic signs of reverse migrations had been spotted before. Over the past decade, evidence has accrued that people returned to Africa after the original ‘out of Africa’ event. And more recently, DNA data suggest that a small...
