The new study looked at the mitochondrial DNA - which is passed down through mothers - of the Khoi and San people in South Africa which appear to have diverged from other people between 90,000 and 150,000 years ago.



The researchers led by Doron Behar of Rambam Medical Center in Haifa, Israel and Saharon Rosset of IBM TJ Watson Research Center in Yorktown Heights, New York, and Tel Aviv University concluded that humans separated into small populations prior to the stone age, when they came back together and began to increase in numbers and spread to other areas.