Finding that much of Africa has Eurasian ancestry was mistaken
An error has forced researchers to go back on their claim that humans across the whole of Africa carry DNA inherited from Eurasian immigrants.
This week the authors issued a note explaining the mistake in their October 2015 Science paper on the genome of a 4,500-year-old man from Ethiopia—the first complete ancient human genome from Africa. The man was named after Mota Cave, where his remains were found (For more about the initial findings, please read the following article: “First Ancient African Genome Reveals Vast Eurasian Migration”).
Although the first humans left Africa some 100,000 years ago, a study published in 2013 found that some came back again around 3,000 years ago; this reverse migration has left its trace in African genomes.
In the Science paper, researchers confirmed this finding. The paper also suggested that populations across the continent still harbour significant ancestry from the Middle Eastern farmers who were behind the back-migration. Populations in East Africa, including Ethiopian highlanders who live near Mota Cave, carried the highest levels of Eurasian ancestry. But the team also found vestiges of the ‘backflow’ migration in West Africans and in a pygmy group in Central Africa, the Mbuti.
Andrea Manica, a population geneticist at the University of Cambridge, UK, who co-led the study, says the team made a mistake in its conclusion that the backflow reached western and central Africa. “The movement 3,000 years ago, or thereabouts, was limited to eastern Africa,” he says.