DNA from 25,000-year-old tooth pendant reveals woman who wore it

DNA that seeped into an elk tooth pendant about 25,000 years in the past has yielded clues in regards to the historic girl who wore it.

The tooth, worn as a necklace bead, in all probability absorbed DNA from the individual’s sweat because it lay in opposition to her chest and neck. Marie Soressi at Leiden University within the Netherlands and her colleagues had been in a position to extract that DNA with out damaging the tooth by a brand new course of that took eight years to develop. The method would possibly reveal unprecedented particulars in regards to the social customs and gender roles of historic populations, says Soressi.

“For the first time, we can link an object to individuals,” she says. “So, for example, were bone needles made and used by only women, or also men? Were those bone-tipped spears made and used only by men, or also by women? With this new technique, we can finally start talking about that and investigating the roles of individuals according to their biological sex or their genetic identity and family relationships.”

Scientists have usually suspected that historic instruments, weapons, decorative beads and different crafted artefacts comprise DNA from the individuals who touched them. But getting DNA out of those objects usually means eradicating sections for evaluation – inflicting everlasting harm. “We absolutely didn’t want to do that,” says Soressi.

To see if DNA might be coaxed out of historic artefacts with out destroying them, Soressi and her colleagues examined quite a few mixtures of chemical compounds and heating regimes on 10 beforehand excavated artefacts from Palaeolithic caves in France. They discovered that putting them in a sodium phosphate resolution and elevating the temperature incrementally from 21°C to 90°C (70°F to 194°F) led to the discharge of comparatively giant quantities of human DNA with no harm to the specimens.

The workforce then examined the process on one other 15 excavated bone specimens from one of many caves. Genetic sequencing revealed DNA from many alternative people – in all probability the scientists and technicians who had labored with the artefacts throughout the years, says Soressi.

To keep away from such fashionable DNA contamination, the researchers then tried their method on 4 tooth pendants excavated by colleagues in Russia and Bulgaria who wore sterile gloves and face masks. Their evaluation revealed principally animal DNA that matched the species used to make the pendants.

One tooth pendant from Denisova collapse Russia, nevertheless, additionally contained human DNA fragments, primarily from a single particular person. There was sufficient genetic materials for the researchers to positively determine a feminine Homo sapiens, along with the elk (Cervus canadensis) that supplied the tooth.

While the human might need rubbed her DNA into the pendant if she had crafted it, the massive amount of DNA recovered suggests she was the person who wore it, says Soressi. “As a porous material, that tooth was likely soaking in sweat,” she says. “It worked like a sponge, pulling in that human DNA and trapping it there for 25,000 years.”

The DNA confirmed that the lady was intently associated to an historic tribe that, up to now, had solely been discovered greater than 1500 kilometres to the east.

Daniella Bar-Yosef Mayer at Tel-Aviv University, Israel, finds the paper “very exciting”, partly as a result of it might assist clarify the aim of historic jewelry. For instance, it’d sign one thing in regards to the id of the wearer or their group, or their marital standing, she says. “If we find them in different contexts on men, on women or children of this species or another species, or different age groups, that would give us some better clues about what they’re meant for.”

The method may also assist resolve long-running scientific debates about whether or not sure artefacts had been made and worn by Homo sapiens or Neanderthals, she provides.

The examine might open the door to DNA analyses of museum artefacts throughout the globe, says David Frayer on the University of Kansas. “Curators are often hesitant to allow their specimens to be damaged for DNA analysis, however small the extraction,” he says. “The absolute strength of this paper is that [their] procedure gets around that. If it can be extended to specimens cleaned long ago, this would represent a great leap forward for ancient DNA work.”