The late stone age, around 70,000 years ago, saw mankind almost became extinct. The total population dwindled to as little as 2000 humans beings. All mankind still lived in Africa at this time and it is believed that they were split into two separate groups by a severe climatological shift that kept the two species apart, one in East Africa - one in South Africa, for nearly half our entire history as a species.
The two groups came together again around 40,000 years ago and the population began a miraculous.recovery before expanding out of Africa to engulf the entire globe. Many archaeologists believe this era heralded the beginning of fully modern human behavior, including abstract thought and complex spoken language. The big surprise was the length of time the populations were separate, believed to be the longest separation in our history.
The genetic study that arrived at these conclusions was conducted by the Genographic Project, a collaboration between National Geographic and IBM which started in 2005, and published in the American Journal of Human Genetics on April 24, 2008. The study concluded that these disparate groups were probably forced apart by the severe drought conditions and as the droughts subsided, allowed the groups to came together again, before man began his expansion out of Africa to populate the globe.
According to National Geographic, "The Genographic Project is a five-year research partnership led by National Geographic Explorer-in-Residence Dr. Spencer Wells. Dr. Wells and a team of renowned international scientists and IBM researchers, are using cutting-edge genetic and computational technologies to analyze historical patterns in DNA from participants around the world to better understand our human genetic roots. The three components of the project are: to gather field research data in collaboration with indigenous and traditional peoples around the world; to invite the general public to join the project by purchasing a Genographic Project Public Participation Kit; and to use proceeds from Genographic Public Participation Kit sales to further field research and the Genographic Legacy Fund which in turn supports indigenous conservation and revitalization projects. The Project is anonymous, non-medical, non-political, non-profit and non-commercial and all results will be placed in the public domain following scientific peer publication."
Amazingly, this information is locked within the human DNA and reveals human history through the ages, ie.the study of anthropology using genetics. Specifically, this study used the mitochondrial DNA (mtDNA) of the Khoi and San people in South Africa. The mtDNA is passed solely from mothers to offspring, never from fathers.
The original pioneering research using mtDNA was the 1980 study by Wesley Brown, then at the University of California at Berkeley, which traced modern humans to a single "mitochondrial Eve," who lived in Africa between what the researchers estimated as between 140,000 and 290,000 years ago. Brown's study found unexpectedly small differences among the mtDNA, signifying a relatively recent origin for modern humans. Brown's data suggested it would take 180,000 to 360,000 years to produce today's diversity starting from a single Eve.
