Study of DNA reveals a migration to the continent about 3,500 years ago, possibly from Eurasia.
In 2012, anthropologists John and Kathryn Arthur of the University of South Florida, St. Petersburg, were led to a cave containing skeletal remains of a hunter-gatherer that died some 4,500 years before. The remains, found in a cave named Mota and located in the Ethiopian highlands, has recently been used as a hiding place for the Gamo during wartime.
In a paper published this week in Science, researchers, using the petrous bone of the inner ear from that skeleton,which can sometimes preserve more DNA than other bones, have been able to map the first prehistoric genome from Africa.
Genomes have been sequenced from Neandertals from Europe, prehistoric herders from Asia, and Paleoindians from the Americas, but because of Africa’s hot and humid climate, little ancient DNA remains for scientists to study. This was disturbing to scientists since Africa is considered the birthplace of the human species, and it is thought that migrations from the continent spanned across the world.
But something startling was found in the process. After sequencing the Mota genome, named for the cave in which the remains were found, the data suggests that a migration into the continent took place some 3,500 years ago, from farmers who probably lived in the Middle East.
The DNA from that group of farmers spread very deep into Africa, even reaching areas that have been considered as isolated, like the Khoisan of South Africa and even pygmies in the Congo.
The research team compared 250,000 base pairs from Mota’s genome against individuals in 81 populations from Europe and Asia, as well as 40 populations in Africa. They found that Mota was most closely related to the Ari, an Ethiopian group still living in the area.
Then they took a look at DNA that was found in the Ari, but was not present in the Mota, and noted the Mota lacked from 4-to-7 percent of the Ari’s DNA.