Genomes have revealed secrets of “Verde Sahara” inhabitants 7,000 years ago

Today, the view of the Rocky Takarkori Shelter in southwest Libya is of infinite sandy dunes and sterile rocks, but 7,000 years ago, this region of the Sahara Desert was a much more exuberant and hospitable place.

Now scientists seeking to understand the origins of the inhabitants of the “Green Sahara” say they have been able to recover the first complete genomes – detailed genetic information – of the remains of two women buried in Takarkori.

In the distant past, the area was a green savannah with trees, permanent lakes and rivers that housed large animals such as hippos and elephants. It was also home to primitive human communities, including 15 women and children who archaeologists found buried in the rock shelter who lived on fishing and created sheep and goats.

“We started with these two (skeletons) because they are very well preserved – the skin, ligaments, fabrics,” said Savino Di Lernia, co -author of New study published on Wednesday in the journal Nature.

The findings marked the first time archaeologists have managed to sequence complete genomes of human remains found in such a warm and arid environment, said Di Lernia, an associate professor of African archeology and ethnoarcheology at the Sapienza University of Rome.

Genomic analysis brought surprises to the study team, revealing that the inhabitants of Sahara Verde were a previously unknown and long isolated population that probably occupied the region for tens of thousands of years.

Mummies reveal secrets of the Sahara past

The excavation of the Rocky Takarkori Shelter, accessible only by 4 × 4 vehicle, began in 2003, with the two female mummies between the first discoveries. “We found the first mummy on the second day of excavation,” said Di Lernia. “We scraped the sand and found the jaw.”

The small community that made its home in the rock shelter possibly migrated there with Africa’s first great human exodus more than 50,000 years ago. The co -author of the study Harald Ringbauer said it was uncommon to find such an isolated genetic ancestry, especially compared to Europe, where there was much more miscegenation. Ringbauer is a researcher and group leader of archaeogenetics at the Max Planck Institute of Evolutionary Anthropology in Leipzig, Germany, who pioneered techniques to obtain genetic material of ancient bones and fossils.

This genetic isolation, according to the study’s authors, suggested that the region was probably not a migration corridor that linked sub -Saharan Africa north of Africa, despite Sahara hospital conditions at the time.

Previous analyzes of rock paintings and animal remains found in archaeological sites throughout the Sahara suggested that their inhabitants were shepherds who raised sheep, goats or cattle, leading some researchers to raise the hypothesis that pastors spread from the nearby orient where agriculture originated.

However, such migration was unlikely, given the genetic isolation of the Takarkori group, the authors of the new report suggested. Instead, the study team has hypothesized that the pasture was adopted through a process of cultural exchange, such as interaction with other groups that already created domesticated animals.

“Now we know that they were isolated in genetic, but not cultural terms. There are many networks we know from various parts of the continent, because we have ceramics from sub -Saharan Africa. We have ceramics from the Nile Valley and the like,” said Di Lernia.

“They had this type of lineage, which is quite ancestral, (who) points to some kind of pleistocene legacy, which needs to be explored,” he said, referring to the period that ended about 11,000 years ago before the current Holocene time.

Louise Humphrey, research leader at the Human Evolution Research Center at the London Natural History Museum, said they agreed with the study’s discoveries: the Takarkori people remained largely genetically isolated for thousands of years, and the grazing in this region was established through cultural diffusion rather than replacing one population with another.

“The DNA extracted from two pastor women who were buried in the rock shelter about 7,000 years ago reveals that most of their ancestry can be tracked to an ancient North African genetic lineage previously unknown,” said Humphrey. She was not involved in the survey, but worked at the Taforalt cave in eastern Morocco, where hunters-gatters 15,000 years ago were buried.

“Future research by integrating archaeological and genomic evidence will probably produce more insights on human migrations and cultural changes in this region,” Humphrey said.

Christopher Stojanowski, Bioarqueologist and Professor at Arizona State University, said one of the most interesting discoveries of the study was the “inference of a moderately large population size and no evidence of endogamy.”

“The fact that there is little evidence of endogamy suggests a degree of movement and connection that is also a bit in disagreement with the idea of ​​a long -time -long green Sahara population,” added Stojanowski, who did not participate in the study.

Ancient DNA recovery is rare

Experts have studied skeletons and unaware artifacts in the place over the years, but attempts to recover DNA from the remains have proven to be elusive. In 2019, scientists were able to recover mitochondrial DNA, which traces the maternal lineage, but getting this DNA did not paint the full picture, Ringbauer said.

“A few years ago, the samples arrived at Leipzig, because we continually perfect new methods over the last few years to extract more than a very small amount of DNA … and the samples had very little DNA,” said Ringbauer, who uses computational tools to analyze genetic data.

Ancient DNA is often fragmented and contaminated. It preserves better in cold environments, not in extreme temperature fluctuations of the largest hot desert in the world. However, Ringbauer and his colleagues from the Max Planck Institute of Evolutionary Anthropology have managed to extract enough DNA from the two mummies to sequency their genomes, a more complete set of genetic material that allowed geneticists to gather information about the ancestry of an individual, not just an individual.

“The full genome carries the DNA of many of its ancestors,” said Ringbauer. “As you go through the genome, you begin to see the different trees of your ancestors. A genome carries the stories of many.”

This content was originally published in genomes reveal secrets of “Sahara Verde” inhabitants 7,000 years ago on CNN Brazil.

Source: CNN Brasil