All humans are South African

Modern humans may have evolved in southern Africa, not eastern Africa as previous research had indicated. A study of genetic markers from six hunter-gatherer groups there found that they have the highest levels of genetic diversity in the world.

It is currently believed by many in the scientific community that modern humans originated in eastern Africa. That's where the earliest anatomically modern skulls have been found. Also, populations from outside of Africa are made up of subsets of the genetic diversity found there. This has made it look as if people came from eastern Africa and then moved outward to colonize the rest of the planet. This "out of Africa" moment is believed to have happened about 60,000 years ago.

In a paper in the journal Proceedings of the National Academy of Sciences, the researchers looked at 580,000 SNPs, or 'snips among human populations, especially hunter-gatherer peoples in Africa.' These are single-nucleotide polymorphisms, DNA sequence variations that are different between members of the same species. They're often called 'genetic fingerprints,' because each individual has a distinct set of snips.

They then looked at the "linkage disequilibrium"of the people they had tested. This is how often a combination of genetic markers shows up in a given population more or less often than would be expected by random chance. In Africa, the hunter-gatherer populations have the lowest linkage disequilibrium, meaning they're the most diverse humans on the planet.

What they found was that the highest positive correlations for the point of origin for humans is south-western Africa -- 300 to 1,000 times more likely than eastern Africa, according to their statistical analysis.

It also seems that the Khoe-San peoples have continuously occupied southern Africa for at least 40,000 years ago.

According to the paper:

Geographic dispersal of modern humans from southern Africa is consistent with the earliest archeological evidence for worked bone awls, inscribed ostrich eggshell and climatic evidence indicating a more hospitable climate in southern African than eastern Africa until 60,000 to 70,000 years ago.

The click-language Khomani and Namibian Bushmen especially are among the most diverse populations, leading to the tantalizing conclusion (which the paper doesn't address) that their language, with its distinctive clicks, might be one of the oldest human languages.