HUMAN SKELETON
The DNA profile of a 2330-year-old skeleton in south Africa has revealed it belongs to a lineage closely related to the original 'Mitochondrial eve'.REUTERS

The DNA from the skeleton of a man who lived 2,330 years ago in southern Africa has established his close connections to the 'mitochondrial eve' or the common tree from which all the different genetic branches evolved, according to Sydney's Garvan Institute of Medical Research.

His lineage, now extinct, of marine hunter gatherers carried a different maternal lineage to early migrants, containing a DNA variant never seen before.

The scientists are excited to have found an individual from a lineage that broke off early in modern human evolution and remained geographically isolated.

This is expected to contribute significantly to refining the human reference genome.

The DNA profile revealed that the tribe is one of the 'earliest diverged' in a region where modern humans are believed to have originated roughly 200,000 years ago.

"One of the biggest issues at present is that no-one is assembling genomes from scratch – in other words, when someone is sequenced, their genome is not pieced together as is," said Professor Vanessa Hayes, expert in African genomes, now heading the genomics lab at Garvan Institute of Medical Research.

"Instead, sections of the sequenced genome are mapped to a reference genome. Largely biased by European contribution, the current reference is poorly representative of indigenous peoples globally."

The team generated a complete mitochondrial genome, using DNA extracted from a tooth and a rib of the skeleton.

Mitochondrial DNA, also known as maternal DNA, is what has provided the first evidence that all humans come from Africa.

According to the anthropologist who worked with the team and reconstructed the identity, the bony growth in the ear canal, known as 'surfer's ear', suggested that the man spent considerable time diving for food in the cold coastal waters. Shells carbon-dated to the same period and found near his grave, confirmed his seafood diet. Osteoarthritis and tooth wear placed him in his fifties.