Vast Eurasian Migration Back to Africa Revealed by Bones of 4,500-year-old Ethiopian Man
An ancient African genome has been sequenced for the first time ever with the discovery of a 4,500-year-old skeleton in a cave in Ethiopia. DNA recovered from the bones suggest that a vast migration of Middle Eastern people into Africa occurred thousands of years ago, reshaping the story of ancient human history.
Due to the fragile nature of human remains in hot climates, getting any kind of DNA from ancient African bodies has been difficult. However, Mota changed that. The ancient skeleton of a hunter-gatherer man who lived 4,500 years ago was found in 2012 in a cave in the highlands of southwestern Ethiopia. Named ‘Mota,’ after the cave, he had been buried in cool, arid conditions, and when scientists tested his petrous bone (found just below the ear) , they were able to retrieve DNA yields as much as 500 times that of other bones, reports NewScientist.
Study co-author Dr. Andrea Manica of the University of Cambridge told the BBC World Service that, “What we were able to get is some very high quality undamaged DNA from which we could reconstruct the whole genome of the individual.
"We have the complete blueprint, every single gene, every single bit of information that made this individual that lived 4,500 years ago in Ethiopia.”
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The Ethiopian Highlands, where the Mota Cave and bones were found. ( CC BY 2.0 )
The milestone findings were published this week in the journal Science. In the abstract, scientists wrote, “We use this genome to demonstrate that the Eurasian backflow into Africa came from a population closely related to Early Neolithic farmers, who had colonized Europe 4,000 years earlier. The extent of this backflow was much greater than previously reported, reaching all the way to Central, West and Southern Africa.”
Mota’s genome revealed him to have pure African DNA, meaning his ancestors had never left Africa. Scientists believe modern humans ( homo sapiens ) first migrated out of Africa 60,000 to 125,000 years ago. The new genetic information, when compared to the makeup of modern African genomes, shows that by 1,500 years after Mota died, the genetic framework of the continent had changed, suggesting that about 3,000 years ago a huge migration occurred back into Africa—and scientists are still stumped as to why.
Map depicting early human migrations out of Africa. Scientists now are dating a mass migration back INTO Africa occurred approximately 3,000 years ago. ( Public Domain )
It remains unclear why people might have made the journey. Smithsonian magazine writes that there’s no evidence to date indicating a change in climate or another major event that might have prompted a mass migration.
A team of archaeologists and Gamo tribesmen of southwest Ethiopia found the Mota cave in the highlands, overlooking a river. It was 14 meters (46 feet) wide and 9 meters (30 feet) high. During excavations, they uncovered the skeleton of an adult male. He had been laid out face down in a burial, body extended, with his hands folded beneath his chin. Radiocarbon dating tests showed he died 4,500 years ago, before the proposed timeline of the Eurasian migration.
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An Ari woman fashions a baking plate in an village in Southern Ethiopia. (David Stanley/ CC BY 2.0 )
These results mean that not only do modern African people possess significantly more Eurasian ancestry than previously realized, but it also makes more clear the movements of ancient groups.
Mota has established a new baseline of genetics in Africa. The flow of Eurasian genetics approximately 3,000 years ago came from the same source that supplied the Neolithic expansion into Europe from the Near East, notes ScienceNewsLine. This proposes that “the direct descendants of the farmers that brought agriculture into Europe may have also contributed new forms of food production in the Horn of Africa.”
Advancing technologies and archaeological discoveries will undoubtedly solve the many mysteries of humanity’s ancient origins.
Of late, genetic studies have shed light on the genomes and ancestries of various groups around the world. This year research showed that Native Americans living in the Amazon bear an unexpected genetic connection to indigenous people in Australasia , suggesting a previously unknown wave of migration to the Americas thousands of years ago.