Modern humans may have originated from southern Africa, say researchers, challenging the age-old view that people came from the eastern part of the continent.
An extensive genetic study, published in 'Proceedings of the National Academy of Sciences' journal, has showed that hunter-gatherer populations in the region had greatest degree of genetic diversity, which is an indicator of longevity.
According to the study's co-author Dr Brenna Henn of Stanford University, 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.
"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," the BBC quoted her as saying.
Dr 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."
She explained that the study's modelling was consistent with the serial founder effect. This refers to a loss of genetic variation when a new population is established by a very small number of individuals from the original, larger population.
"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," she said.
Chris Stringer, a leading palaeontologist based at the Natural History Museum, London, said: "This is a landmark study with far more extensive data on...hunter gatherer groups than we've ever had before, but I am cautious about localising origins from it."