A "ghost" branch of humanity has been found

Tom Howarth, This 7,000-year-old mummy DNA has revealed a ‘ghost’ branch of humanity, BBC Science Focus, April 2, 2025.

Scientists have successfully analysed the DNA of two naturally mummified individuals from the Takarkori rock shelter, in what is now southwestern Libya. Their findings reveal something extraordinary: these ancient people belonged to a previously unknown branch of the human family tree.

The two women belonged to a so-called 'ghost population' – one that had only ever been glimpsed as faint genetic echoes in modern humans, but never found in the flesh.

“These samples come from some of the oldest mummies in the world,” Prof Johannes Krause, senior author of the new study, told BBC Science Focus. It is, he explained, remarkable that genome sequencing was possible at all, given hot conditions tend to degrade such information.

What happened?

First, they found that this lost lineage split from the ancestors of sub-Saharan Africans around 50,000 years ago – about the same time other groups were beginning to migrate out of Africa.

Remarkably, this group then remained genetically isolated from other groups of humans for tens of thousands of years, all the way through to the time when these two women died around 7,000 years ago.

“It’s incredible,” Krause said. “At the time when they were alive, these people were almost like living fossils – like something that shouldn’t be there. If you’d told me these genomes were 40,000 years old, I would have believed it.”

This long-term isolation reveals two major insights. First, while the 'Green Sahara' – which lasted from 15,000 to 5,000 years ago – was a lush habitat for humans, it didn’t serve as a migration corridor between north and sub-Saharan Africa, as many scientists had previously assumed.

Second, there was some genetic mixing with populations to the North, including Neanderthals. But it was limited – far less than in non-African populations, which carry about ten times more Neanderthal DNA than the Takarkori people.

H/t Tyler Cowen.

Here's the research report:

Salem, N., van de Loosdrecht, M.S., Sümer, A.P. et al. Ancient DNA from the Green Sahara reveals ancestral North African lineage. Nature (2025). https://doi.org/10.1038/s41586-025-08793-7

Abstract: Although it is one of the most arid regions today, the Sahara Desert was a green savannah during the African Humid Period (AHP) between 14,500 and 5,000 years before present, with water bodies promoting human occupation and the spread of pastoralism in the middle Holocene epoch1. DNA rarely preserves well in this region, limiting knowledge of the Sahara’s genetic history and demographic past. Here we report ancient genomic data from the Central Sahara, obtained from two approximately 7,000-year-old Pastoral Neolithic female individuals buried in the Takarkori rock shelter in southwestern Libya. The majority of Takarkori individuals’ ancestry stems from a previously unknown North African genetic lineage that diverged from sub-Saharan African lineages around the same time as present-day humans outside Africa and remained isolated throughout most of its existence. Both Takarkori individuals are closely related to ancestry first documented in 15,000-year-old foragers from Taforalt Cave, Morocco2, associated with the Iberomaurusian lithic industry and predating the AHP. Takarkori and Iberomaurusian-associated individuals are equally distantly related to sub-Saharan lineages, suggesting limited gene flow from sub-Saharan to Northern Africa during the AHP. In contrast to Taforalt individuals, who have half the Neanderthal admixture of non-Africans, Takarkori shows ten times less Neanderthal ancestry than Levantine farmers, yet significantly more than contemporary sub-Saharan genomes. Our findings suggest that pastoralism spread through cultural diffusion into a deeply divergent, isolated North African lineage that had probably been widespread in Northern Africa during the late Pleistocene epoch.