Ancient Human Genome From Africa Sequenced for the First Time

Entrance to Mota Cave
Thee entrance to the Mota cave in the Ethiopian highlands, where the remains containing the ancient genome were found. Kathryn and John Arthur

A 4,500-year-old genome from Africa has been sequenced, and the results may shift current understandings of the migratory history of humans out of the birthplace of humanity.

A study reporting the projectthe first time an ancient human genome from Africa was sequencedwas published in the journal Science on Thursday. The genetic material used was extracted from the skull of a man discovered in 2012, buried facedown in the Mota cave. The cave is situated almost 2,000 meters above sea level in southwestern Ethiopia.

The research throws new light on a mysterious migratory event which occurred around 3,000 years ago, when people in regions of Western Eurasia such as the Levant (which includes modern-day Cyprus, Israel, Jordan, Lebanon, Palestine and Syria) and Anatolia (present-day Turkey) moved back to the Horn of Africa. In sequencing the genome of the Mota man and comparing it to modern regional genomes, the researchers found that present East Africans have as much as 25 percent Eurasian ancestry, suggesting the migration was on a much bigger scale than previously thought.

"We initially thought that it was a small movement," says Andrea Manica, an evolutionary ecologist at the University of Cambridge and the study's lead author. "Now we know that...for every four people there were in East Africa 3,000 years ago, there was one person coming in from West Eurasia." Scientists are currently stumped as to what caused this mass migration, but it coincides with the arrival of Near Eastern crops such as wheat and barley in Africa, indicating that the migrants may have brought new forms of agriculture to the continent.

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Ancient human genomes have been discovered and sequenced before, but the genetic material has often been taken from places such as Siberia, where colder temperatures mean the DNA is preserved over thousands of years. What makes this discovery unique, according to Manica, is that the DNA is from remains found on the African continent. The Out-of-Africa hypothesis, which posits that modern humans originated in Africa and migrated out of the continent around 100,000 years ago, is one of the major scientific theories into human origins.

"Most of the questions that we ask about human history are normally asked with some sort of African reference," says Manica. "When we try to retrace the exact genes that we might have exchanged with Neanderthals, knowing that we now have a complete clean reference we have an African [genome] that is really just African will make life much easier."

Ancient Human Genome From Africa Sequenced for the First Time | Tech & Science