Entrance to the cave in which Motta Man was discovered. GENOME. Modern man, who appeared in Africa 200,000 years ago, left it several times to populate the planet... but he also returned! This is demonstrated by a recent study which highlights the "return" 3,000 years ago to the African continent of a large wave of migration from the Middle East. A team of scientists led by Andréa Manica (University of Cambridge, Great Britain) has just announced in the journal Science to have been able to determine it thanks to the first complete sequencing of a prehistoric African genome:That of "the man of Motta", a hunter-gatherer who lived 4,500 years ago on the highlands of Ethiopia and whose fossil remains were discovered in 2012 by archaeologists John W. Arthur and Kathryn Weedman Arthur, from the University of South Florida (USA).
The genetic material that allowed the reconstitution of his entire genome was taken from the petrous bone of his inner ear (where DNA is preserved better than in other parts of the skeleton). Thanks to the sequencing of this genome, which they were able to compare with that of modern humans, the researchers demonstrated for the first time the existence of a major migration towards Africa of populations of farmers from the Near East about 3,000 years ago. "These data confirm the evidence of a Eurasian genetic component in the Horn of Africa, which archeology, linguistics and current population genetics had already suggested" , explains Céline Bon, paleogenetician at the National Museum of Natural History, in Paris. Because Motta Man, present in Africa more than 4000 years ago, does not have these same characteristics. Proof that it dates from "before" the arrival of populations from the Middle East.
Africa has had an extraordinary genetic history !"
This sequencing also made it possible to demonstrate that the population that reached Africa 3,000 years ago is genetically close to those of the first farmers who also left from the Near East and arrived in Europe 7,000 years ago. Another lesson, and not the least:"This genome will also allow us to refine our studies in relation to the interbreeding between modern man and Neanderthal man" , continues Céline Bon. Indeed, these migrations in Africa having taken place well after the interbreeding of the populations of the Near East with Neanderthals, the current African populations would in fact possess 0.2% to 0.7% of Neanderthal components, which we do not hadn't imagined until then. Elements of this genome have been found in very distant current groups such as the Khoisan of South Africa, the Yoruba of Nigeria or the Mbuti pygmies of the forests of the Democratic Republic of Congo, proving the depth of the propagation of these genes . "What this study shows above all is that between migrations, immigrations and interbreeding, Africa has had an extraordinary genetic history !”, concluded Céline Bon.