The 2,000-year-old bones of a boy found on a beach in South Africa have provided more grounds to challenge the prevailing theory that modern humans had a single origin in north-eastern Africa.
That fraying theory, based on fossils found at Omo Kibish and elsewhere in Ethiopia, dates the emergence of modern humans to about 180,000 years ago. However, by using DNA analysis as a ‘molecular clock’ to calculate the length of time since the boy’s ancestors diverged genetically from other groups of modern humans, scientists in South Africa and Sweden estimate that modern humans must have existed between 260,000 and 350,000 years ago.
This pushing back of the estimated date of the emergence of modern humans by at least 100,000 years is roughly in line with research published in June that dated human remains and other artefacts found at the Jebel Irhoud archaeological site in Morocco as about 300,000 years old.
The finding lends weight to the hypothesis there was not just a single cradle of modern humankind in north-eastern Africa but, rather, an entire continental nursery.
“It seems that both genetics and archaeology are converging on this point that there might be multiple places in Africa that archaic humans transitioned from Homo erectus to H. heidelbergensis to modern humans,” says Carina Schlebusch of Uppsala University in Sweden, lead author of the new research, published in the journal Science.