The oldest genomes of our species sequenced

Dec. 13 () –

An international team led by researchers at the Max Planck Institute for Evolutionary Anthropology has sequenced the oldest modern human genomes to date.

The genomes were recovered from seven individuals who They lived between 42,000 and 49,000 years ago in Ranis (Germany) and Zlaty kun (Czech Republic). These genomes belonged to individuals who were part of a small, closely related human group that separated from the population that left Africa about 50,000 years ago and later settled in the rest of the world.

Although they split early, the Neanderthal DNA in their genomes dates back to an admixture event common to all people outside of Africa, which Researchers date it to about 45,000-49,000 years ago, much later than previously believed.

After modern humans left Africa, they encountered and interbred with Neanderthals, resulting in about two to three percent of Neanderthal DNA can be found in the genomes of all people outside of Africa today. . However, little is known about the genetics of these early pioneers in Europe and the timing of the mixing of Neanderthals with non-Africans.

A key site in Europe is Zlaty kun in the Czech Republic, where a complete skull from a single individual who lived around 45,000 years ago was discovered and previously genetically analyzed. However, due to the lack of archaeological context, It was not possible to link this individual to any archaeologically defined group. A nearby site, the Ilsenhöhle in Ranis in Germany, about 230 km from Zlaty kun, is known for a specific type of archaeology, the Lincombian-Ranisian-Jerzmanowician (LRJ), dating back to about 45,000 years ago.

It has long been debated whether the LRJ culture was produced by Neanderthals or early modern humans. Although mainly small bone fragments are preserved in Ranis, a previous study was able to analyze the mitochondrial DNA of thirteen of these remains and found that they belonged to modern humans and not Neanderthals. However, since the mitochondrial sequence only constitutes a tiny part of the genetic information, Relationships with other modern humans remained a mystery.

A new study published this December 12 in Nature analyzed the nuclear genomes of all thirteen Ranis specimens and found that they represented at least six individuals. The size of the bones indicated that two of these individuals were babies and, genetically, three were males and three were females. Interestingly, among these individuals were a mother and a daughter, as well as other more distant biological relatives. The team also sequenced more DNA from the female skull found in Zlaty kun, producing a high quality genome for this individual.

“To our surprise, we discovered a fifth or sixth degree genetic relationship between Zlaty kun and two Ranis individuals.” The lead author of the study, Arev Sümer, says in a statement that “this means that Zlaty kun was genetically part of the extended Ranis family and probably also made LRJ-type tools.”

Among the six Ranis individuals, one bone was particularly well preserved; in fact, it is the best preserved modern human bone from the Pleistocene for DNA recovery. This allowed the team to obtain a high-quality genome of this male individual, known as Ranis 13. Together, the genomes of Ranis13 and Zlaty kun represent the oldest high-quality modern human genomes sequenced to date. By analyzing genetic variants related to phenotypic traits, they discovered that Ranis and Zlaty kun individuals presented variants associated with dark skin and hair color, as well as brown eyes, reflecting the recent African origin of this early European population.

By analyzing segments inherited from the same ancestor in the genomes of Ranis and Zlaty kun, the researchers estimated that their population consisted of, at most, a few hundred individuals that they could have been dispersed over a wider territory. The authors found no evidence that this small population of early modern humans contributed to the formation of later Europeans or any other global population.