Scientists are beginning to sequence the genomes of humans who lived in Africa thousands of years ago – shedding light on our origins.
The research was announced this week at the annual meeting of the Society for Molecular Biology & Evolution. A group of scientists said they examined the genomes of 15 ancient people who lived up to 6,000 years ago in eastern and southern Africa.
Africa is, of course, thought to be the place from which humans started spreading around the world about 50,000 years ago. As Science points out, it’s also the region where people are most genetically diverse. However, the arrival of early adopters of agriculture 2,000 years ago, known as the Bantu, wiped out most of the genetic footprint of early Africans in the region.
Only one ancient African genome has been sequenced so far, an Ethiopian dating back 4,500 years. Now, Pontus Skoglund from the Harvard University has gathered DNA from 15 Africans dating between 500 and 6,000 years old.
Nature notes that ancient African DNA has been overlooked due to the country’s climate, with the heat speeding up the deterioration of DNA. However, advances in removing contamination, and the discovery that a tiny inner ear bone was “chock full of ancient DNA”, has opened up Africa’s past to researchers.
Early results from the research show that ancient humans moved around the continent more than expected. For example, it appears that Southern Africans may have split off from Western Africans several thousand years ago.
A second study, let by Carina Schlebusch from Uppsala University in Sweden, also examined the DNA of ancient Africans. They found that modern farmers had Bantu DNA in their genomes, among other findings.
This follows on from the finding earlier this week that humans and Neanderthals may have interbred more than 270,000 years ago. This paints a dramatic new picture of how our two species interacted.
"We are realizing more and more that the evolutionary history of modern and archaic humans was a lot more reticulated than we would have thought 10 years ago," study co-author Fernando Racimo of the New York Genome Center told New Scientist about that research. "This and previous findings are lending support to models with frequent interbreeding events."