New genetic research reveals that a small group of hunter-gatherers now living in Southern Africa once was so large that it comprised the majority of living humans during most of the past 150,000 years. Only during the last 22,000 years have the other African ethnicities, including the ones giving rise to Europeans and Asians, become vastly most numerous. Now the Khoisan (who sometimes call themselves Bushmen) number about 100,000 individuals, while the rest of humanity numbers 7 billion. Their lives and ways have remained unaltered for hundreds of generations, with only recent events endangering their hunter-gatherer lifestyles. The study's findings will be published in the journal Nature Communications on 4 December 2014.

By comparing nearly all the genes of these individuals -- their genomes -- with the genomes of 1,462 people from around the world, the researchers discovered that the inflow of new genes into the Khoisan peoples has been quite restricted the past 150,000 years, indicating that this large hunter-gatherer culture was physically isolated for most of its history and that its men typically did not take wives from outside the group.

"Khoisan hunter-gatherers in Southern Africa always have perceived themselves as the oldest people" said Stephan Schuster, a former Penn State University professor, now at Nanyang Technological University in Singapore and a leader of the research team, which includes scientists at Penn State and other research universities in the United States, Brazil, and Singapore. The Nature Communication paper analyzes five study participants from different tribes in Namibia. The study investigated 420,000 genetic variants across 1,462 genomes from 48 ethnic groups in populations worldwide. These analyses reveal that Southern African Khoisans are genetically distinct not only from Europeans and Asians, but also from all other Africans. The paper's first author Hie Lim Kim, formerly at Penn State and now at Nanyang Technological University, said "It is fascinating to unravel the population history of humankind over the last 150,000 years."