[Reading Science] A 20,000-Year-Old Deer Tooth Necklace That Became a 'Time Machine'

Max Planck Institute in Germany Succeeds in DNA Extraction and Analysis
"20,000-Year-Old Large Deer Tooth Material Used by Female Modern Humans"

Genetic material from a person's skin remains on necklaces or rings that they wear for a long time. Commonly, forensic teams extract DNA from jewelry left at crime scenes to identify suspects, confirm victims' identities, or reconstruct the circumstances at the time. However, scientists have recently attracted attention by extracting DNA from jewelry dating back as far as 20,000 years ago, revealing information about the wearers' lineage based on advanced DNA extraction and analysis techniques. Cutting-edge genetic technology is becoming a key that opens the door to the past, much like a time machine.

Deer tooth necklace discovered in the Denisovan Cave in Siberia. Photo by Max Planck Institute for Evolutionary Anthropology, Germany.

On the 4th (local time), the international academic journal Nature published a paper from the Max Planck Institute for Evolutionary Anthropology in Germany presenting these research findings. The research team focused on a necklace discovered in the 'Denisova Cave' in the Altai Mountains of Siberia, Russia. This cave has been inhabited by various ancient human species for approximately 300,000 years and is notably where traces of the Denisovans?a new ancient human species somewhat distant from modern humans?were found.

The team implemented the idea that, as is done in current forensic science, it would be possible to extract DNA from both the animal and the user from the animal tooth necklace found there. Typically, animal genetic material is stored deep within the pores of bones and teeth. Also, artifacts like necklaces or rings that frequently contact the skin usually retain the DNA of past users. However, 'time' was a barrier. Because the items were so ancient, even if genetic material remained, extraction and analysis seemed difficult. Yet, the team succeeded in discovering and extracting DNA from inside the surface pores by soaking the necklace in cold saltwater and gradually warming it. Remarkably, the necklace was not damaged during this process.

The results of analyzing the DNA obtained were even more astonishing. First, the necklace was confirmed to be made from the teeth of a large deer (wapiti or elk) that lived approximately 19,000 to 25,000 years ago. Particularly, DNA nucleic acid analysis suggested that this ornament was made or worn by female modern humans (Homo sapiens) living in northern Eurasia during the same period. This is the first time traces of northern Eurasian modern humans have been found in this region; previously, such remains had only been excavated much farther east.

Elena Essel, a researcher at the Max Planck Institute for Evolutionary Anthropology who participated in the study, explained, "The technology developed in this research is like riding a time machine," adding, "Through each sample, we can gain more inferences and information about the lives of ancient humans." Co-author Elena Zavala, a genetics professor at the University of California, Berkeley, said, "We can study ancient humans through the tools they used," and "Unlike other methods, this does not destroy the artifacts."

An ancient Homo sapiens woman wearing a deer tooth necklace. Image source=Max Planck Institute for Evolutionary Anthropology, Germany

However, the technology also has clear drawbacks. There is a possibility of contamination by modern DNA from handlers during the study of artifacts. Even if contamination is avoided, the DNA extraction method itself takes a long time and requires sophisticated technology and specialized research facilities to minimize sample contamination.

Ludovic Orlando, a molecular archaeologist at the French Paul Sabatier University who did not participate in the study, evaluated, "This technology is not万能 (万能 means 'all-powerful' or 'universal' in Japanese; since the original text is Korean, this is likely a translation artifact; it should be 'all-encompassing' or '万能' should be translated as 'all-purpose' or '万能' is not appropriate here), but it can provide important discoveries from animal bones or teeth fragments," adding, "It also allows us to examine the demographic characteristics of people who interacted with animals."