The deer tooth necklace that a woman made and wore 20,000 years ago in Siberia

Paleolithic burials and grave goods are very scarce.

Oliver Thansan
Oliver Thansan
04 May 2023 Thursday 06:26
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The deer tooth necklace that a woman made and wore 20,000 years ago in Siberia

Paleolithic burials and grave goods are very scarce. That is why archaeologists consider themselves extremely lucky when they find an artifact from that time made of stone, bone or tooth. These items always provide important details about early humans' subsistence strategies, behavior, and culture.

With the aim of linking these objects with their former owners, researchers from the Max Planck Institute have developed a new method that makes it possible to isolate the DNA present without having to destroy anything. Although generally rarer than stone tools, the scientists focused specifically on bones and teeth because they are more porous and more likely to retain genome present in skin cells, sweat, and other bodily fluids.

Scientists have for the first time successfully isolated ancient human genes from a Paleolithic artifact, a perforated deer tooth discovered in southern Siberia. This is how they managed to determine the sex of the person who used it, leaving the sample fully intact.

"Preserving the integrity of the artifacts, including the microstructures on their surface, was a top priority," says Marie Soressi, an archaeologist at Leiden University who supervised the work along with Matthias Meyer, Max Planck's geneticist. "By washing the artifacts at temperatures up to 90°C, we are able to extract DNA from the wash waters, keeping the utensils intact," she adds.

The first test was carried out with a prehistoric group recovered from the French cave of Quinçay, which was excavated between the 70s and 90s of the last century. Although in some cases it was possible to identify the genetic code of the animals from which the artifacts were made, the vast majority of the DNA obtained came from people who had handled the artifacts during or after excavation, making identification difficult. of ancient human genes.

Using measures focused on avoiding modern contamination (using gloves and face masks), the researchers managed to study three tooth pendants from the Bacho Kiro cave in Bulgaria, home to the oldest safely dated modern humans in Europe, they explain in a paper. published in the journal Nature. But no ancient human DNA could be identified in these samples either.

In 2019, however, the archaeologists Maxim Kozlikin and Michael Shunkov, who excavated the famous Denisova cave in Russia, managed to succeed, despite the fact that they were unaware of the new method developed at the Max Planck Institute. Russian experts excavated and neatly removed an Upper Paleolithic stag tooth pendant.

From there, Leipzig geneticists isolated not only the DNA of the animal itself, a wapiti deer, but also vast amounts of ancient human genome. “The amount of human genes we recovered from the pendant was extraordinary,” says Elena Essel, “almost as if we had taken a sample directly from a human tooth.”

Using analysis of mitochondrial DNA, the small part of the genome that offspring inherit exclusively from the mother, the researchers concluded that most of the DNA likely originated from a single individual. Using the human and wapiti mitochondrial genomes, they were able to estimate the age of the pendant to be between 19,000 and 25,000 years. And they did it without using carbon 14 dating.

Based on the number of X chromosomes found, the German specialists determined that the pendant was made, worn or worn by a woman. They also discovered that this female was closely related genetically to ancient individuals from eastern Siberia, the so-called "ancient North Eurasians."

Bone remains from this culture had already been previously analyzed. “Forensic scientists will not be surprised that human DNA can be isolated from an object that has been handled a lot,” says Matthias Meyer, “but it is fascinating that this is still possible after 20,000 years.”

The scientists now hope to apply their method to many other objects made from bones and teeth during the Stone Age to learn more about the genetic ancestry and sex of the people who made, wore or wore them in that remote age.