Archaeologists are not immune to misunderstandings. Again and again they come across prehistoric objects made of stone, bones or teeth of animals. It is such tools and pieces of jewelry that tell of vanished cultures, of how people treated each other and how skilled they were. But with the attribution it is one thing: what belonged to whom? Did a tool belong to whoever’s bones are nearby – or do the relics just happen to be together?
So far, such questions can hardly be clarified. But archaeologists may be able to provide answers during future excavations, thanks to a method reminiscent of forensics: thanks to genetic traces.
If you wash the artefacts at 90 degrees, pieces of genetic material get into the washing water
Scientists led by Elena Essel from the Max Planck Institute (MPI) for evolutionary research in Leipzig anthropology succeeded in extracting human genetic material from the surface of an object from the Stone Age. Like the team, which also included Nobel Prize winner Svante Pääbo, now in the journal Nature reported, this may open up new possibilities for research. Because in order to examine genetic material from prehistory, paleogeneticists have so far needed human fossils – ideally a skull where there is a good chance of being able to extract old DNA from the petrous bone, for example. With luck you can also find old bone or faecal particles with genetic material in sediments. But now there are new options.
In a statement from the MPI, Elena Essel compared the technology to a washing machine and a phosphate-based detergent: “If we wash the artefacts at temperatures of up to 90 degrees Celsius, we are able DNA from the washing water while leaving the artifacts intact.” Thus, the researchers managed to identify genetic material from a pendant made of deer tooth, made about 19,000 to 25,000 years ago and found in the Denisova Cave in southern Siberia. From it Not only did the scientists obtain a genetic profile of the wapiti deer that originally owned the tooth, but they also found large amounts of genetic material from a human female who is believed to have once worn the pendant and who was closely related to humans who lived farther east at the time lived in Siberia.
However, the technology is not trivial. As the researchers in Nature report, initial analyzes failed because the finds examined were contaminated with the genetic material of archaeologists. They therefore concentrated on fresh excavations and worked with gloves and face masks, and the finds were immediately packed in plastic bags.
The technique was developed for bones and teeth. Objects made from skeletal components are more porous, so genetic material from skin cells, sweat and other bodily fluids is more likely to be found on their surfaces than in stone tools, the researchers explain. “Forensic scientists will not be surprised that human DNA can be isolated from an object that has been used a lot,” says biochemist Matthias Meyer from the MPI. “But it’s amazing that this is still possible after 20,000 years.” It is conceivable that archaeological excavations will increasingly look like securing evidence at a crime scene in the future.