First big efforts to sequence ancient African DNA reveal how early humans swept across the continent

By Elizabeth Pennisi

The study of ancient human DNA has not been an equal opportunity endeavor. Early Europeans and Asians have had portions of their genomes sequenced by the hundreds over the past decade, rewriting Eurasian history in the process. But because genetic material decays rapidly in warm, moist climates, scientists had sequenced the DNA of just one ancient African. Until now.

This week, at the annual meeting of the Society for Molecular Biology & Evolution here, scientists announced that they had partially sequenced 15 ancient African genomes, with representatives from all over sub-Saharan Africa. And another group—whose work is still unpublished—has sequenced seven more ancient humans from South Africa. “[Finding] ancient genomes from Africa is pretty amazing,” says Anna-Sapfo Malaspinas, a population geneticist at the University of Bern, who was not involved in either project.

Africa has long been called the “cradle of humanity,” from which our earliest human ancestors spread across the rest of the world some 50,000 years ago. Africa is also where people—ancient and modern—are most genetically diverse. But how such groups, from the Hadza of East Africa to the Khoe-San of Southern Africa, came to be is a mystery. That’s in part because some 2000 years ago, early adopters of agriculture known as the Bantu spread across the continent, erasing the genetic footprint of other Africans. The one ancient African genome that has been sequenced—an Ethiopian who lived some 4500 years ago—has shed little light on this mystery.   

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