In aggregate, the genetic variations found in this group lie beyond the spectrum of previously characterized human diversity. This is true even though the contemporary hunter-gatherers of southern Africa primarily descend from southern African forebears.
What sets it apart?
Estimates regarding the timeline of the divergence of this ancient south African population from modern populations suggest the separation occurred more than 200,000 years ago, approximately coinciding with the emergence of modern humans. However, this group was not an unusual, sequestered community; projections of its population size based on genetic variation imply it was quite large.
Instead, the researchers propose that climatic and geographical factors kept this group distinct from other African populations, indicating that southern Africa may have acted as a climatic haven, providing a secure locale from which modern humans could radiate to other parts of the continent under favorable environmental conditions. This aligns with findings that some of the ancient populations in eastern and western Africa exhibited some southern African genetic variations roughly 5,000 years ago.
Concerning genetic characteristics, the population displayed traits similar to others around them at the time: brown eyes, high skin pigmentation, and a lack of lactose tolerance. None of the elder members exhibited genetic immunity to malaria or sleeping sickness that are observed in current populations. In terms of mutations affecting proteins, the most prevalent alterations are located in genes related to immune responses, a trend noted in numerous human populations. Uniquely, genes influencing kidney functions also demonstrate considerable variation.
Thus, there is nothing particularly unique or modern visible in this population, especially when compared to any other African groups known to exist during the same era. Yet, they are distinctive in indicating a sizable, stable, and isolated community apart from other African populations of their time. In the future, we are likely to receive more data that would integrate this population into a comprehensive narrative of human evolution. For now, however, its existence remains somewhat puzzling, considering how often other populations mixed in historical contexts.
