Modern humans 'originated from southern Africa'

An extensive genetic study has suggested that modern humans may have generated out of southern Africa.

According to the researchers, the hunter-gatherer populations in the region had the greatest degree of genetic diversity, which is an indicator of longevity.

Brenna Henn from Stanford University, California, said the study reached two main conclusions.

"One is that there is an enormous amount of diversity in African hunter-gatherer populations, even more diversity than there is in agriculturalist populations," the BBC quoted her as saying.

“This is a landmark study, with far more extensive data on... hunter gatherer groups than we have ever had before, but I am cautious about localising origins from it.”

"These hunter/gatherer groups are highly structured and are fairly isolated from one another and probably retain a great deal of different genetic variations - we found this very exciting," she said.

Henn added, "The other main conclusion was that we looked at patterns of genetic diversity among 27 (present-day) African populations, and we saw a decline of diversity that really starts in southern Africa and progresses as you move to northern Africa."

"Populations in southern Africa have the highest genetic diversity of any population, as far as we can tell. So this suggests that this might be the best location for (the origins) of modern humans.”

Chris Stringer, a leading palaeontologist based at the Natural History Museum, London, said, "The new paper... suggests that the genes of the Namibian and Khomani bushmen (southern Africa), Biaka pygmies (Central Africa) and the Sandawe (East Africa) appear to be the most diverse, and by implication these are the most ancient populations of Homo sapiens."

Stringer said that he no longer thought that there was a single "Garden of Eden" where we evolved.

Instead, he said, "distinct populations in ancient Africa probably contributed to the genes and behaviours that make up modern humans".

The study appears in the Proceedings of the National Academy of Sciences.