Ancient DNA Reveals Unknown Population in Green Sahara

Genetic analysis of two women buried in a cave in southern Libya reveals a previously unknown population that inhabited the Sahara 7000 years ago when it was a lush savanna. The findings, reported this week, are the first ancient genomes recovered from anywhere in the Sahara, according to University of Oxford archaeologist Peter Mitchell. The women, who died around 5000 B.C.E. [Before Common Era], were discovered at the Takarkori rock shelter in southwestern Libya, excavated between 2003 and 2006. Archaeologist Savino di Lernia of Sapienza University noted that the site "is now in the middle of the desert," but was once near a year-round lake. The bodies were naturally mummified, preserving their DNA. Analysis suggests their ancestors were distinct from sub-Saharan Africans and did not originate from the Levant. Geneticist Johannes Krause from EVA [Max Planck Institute for Evolutionary Anthropology] stated that researchers previously thought the area was a corridor for migration from sub-Saharan Africa. The woman with the best-preserved DNA had minimal Neanderthal ancestry, "10 times less than people living outside sub-Saharan Africa today." The women's mitochondrial DNA indicates their ancestors originated from an African population that contributed to early modern human migration to Europe. Paleogeneticist Nada Salem from EVA [Max Planck Institute for Evolutionary Anthropology] notes this population is "separate from sub-Saharan Africa, but also distinct from people outside Africa today." Despite pottery similarities suggesting contact with North Africa, the genes show no mixing with new populations, even with the introduction of herding around 8300 years ago. Di Lernia suggests, "The green Sahara wasn't a corridor for the movement of people, but for sure it was a corridor for ideas and technology." Mitchell cautions that more data is needed due to limited samples, as political tensions hinder further excavations. "Exciting as this is, it's difficult to be absolutely sure how much to make of it based on two data points," Mitchell says.