Durban - Studying the DNA of the 2 000-year-old remains of a boy found near Ballito Bay in KwaZulu-Natal has shed new light on the transition from archaic to modern humans, with findings helping to "rewrite human history".
The boy, of hunter-gatherer descent, lived in a time before migrants from further north in Africa reached South Africa's shores.
Researchers could thus use his DNA to estimate the split between modern humans and earlier human groups as happening between 350 000 and 260 000 years ago.
"This means that modern humans emerged earlier than previously thought," said Uppsala University population geneticist Mattias Jakobsson.
Jakobsson headed the project with University of Johannesburg Stone Age archaeology professor, Marlize Lombard.
Geneticists from the Swedish University and the University of the Witwatersrand collaborated in the research.
The team's findings, the result of a fascinating interplay between genetics and archaeology, were presented in the early online release of the Science research journal on Thursday.
Their estimate of the split coincided with the Florisbad skull, which was discovered in the Free State in 1932, and dated to around 259 000 years old.
"It now seems that at least two or three Homo species occupied the southern African landscape during this time, which also represents the early phases of the Middle Stone Age," said Lombard.
They team reconstructed the full genome of the Ballito Bay child and those of six other individuals from KwaZulu-Natal.
Three Stone Age hunter-gatherers, who lived between 2 300 and 1 800 years ago, were found to be genetically related to Khoi-San groups living in southern Africa today.
Four Iron Age farmers, who lived between 500 and 300 years ago, were genetically similar to present-day Bantu-speakers.
Three of the Iron Age individuals carried at least one form of genetic protection from malaria. Two had at least one sleeping-sickness-resistance variant in a specific gene.
The DNA of the Stone Age individuals did not carry these protective factors.
Looking at fossil, ancient DNA and archaeological records as a whole suggested that the transition from archaic to modern humans may not have occurred in only one place in Africa, according to the study.
Homo sapiens may have evolved from older forms in several places in Africa with gene flow between groups from different places, said Uppsala university biology researcher Carina Schlebusch.