Woman’s DNA discovered in 20,000 year old deer-tooth pendant | CBC Radio

Scientists have discovered a woman’s DNA preserved in a 20,000 year old deer-tooth pendant. 

The artifact, which was discovered in 2019 in the Altai Mountains of Siberia, was analyzed by a German research team that developed advanced techniques for extracting and studying ancient DNA.

“This was exactly what we were hoping for,”  said geneticist Elena Essel, a member of the team at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. 

“It was clear that a human handled it and also potentially was wearing it, so we actually were hoping that … the maker or user or wearer of this artifact left some of his or her DNA on this pendant.”

The group’s work was published this week in the journal Nature.

The pendant was discovered in Denisova cave, which has been a rich source of archeological finds about early humans in Eurasia for decades. 

The cool and dry conditions in the cave have made it possible for scientists to recover preserved DNA left behind by ancient Denisovans, Neanderthals and humans, all of whom occupied the cave at different times over 40,000 years.

Unusual discovery

What makes the study of this pendant unusual is that Essel and her colleagues were able to extract human DNA from animal remains.

The pendant was made from a canine tooth of a species of deer known as wapiti. There is a hole drilled in the tooth, suggesting it was threaded with a cord and could’ve be worn.

But Essel says they aren’t sure how the pendant was worn. 

“It’s possible that it was worn like a necklace. Maybe it was part of a bigger necklace that contained more of those pendants,” said Essel. 

“Or maybe it was also worn close to the belt, as an adornment of the clothes.”

Essel said that bones and teeth are very good candidates for extracting DNA because they are porous and the minerals in them binds to and protects the DNA. 

In this case, Essel says it seems that contact with skin, sweat, saliva or blood allowed the wearer’s DNA absorb into the tooth.

DNA extraction

Essel says the group modified a DNA extraction technique to make it work for artifacts.

“I really like to compare it to a washing machine,” said Essel.

“We put the whole artifact into a sodium phosphate buffer and then we heat it sequentially up to 90 degrees. This allows us to release the DNA that is trapped in the bone matrix of the pendant.”

Essel says it’s innovative because it’s non-destructive and preserves the original artifact. In this case, it also extracted a remarkably complete set of DNA sequences. 

“There’s the mitochondrial DNA that is only inherited from mother to child and that we were able to reconstruct almost completely at a very high accuracy,” Essel said.

“Then one has the nuclear DNA, which is 3 billion bases long. So it’s a lot of DNA. And for that we didn’t try to recover the full genome. For that we were able to recover roughly 70 per cent.”

‘Like a gender reveal’

They were able to genetically date the pendant to an estimated age range of 19,000 to 25,000 years old. 

And the remarkable preservation of the DNA allowed Essel and her team to determine a lot of information about the wearer, and place her on the human family tree. 

“The DNA that we recovered is closest to a population that was also present during that time in the Northern Eurasian area,” said Essel. 

But Essel says the most exciting discovery was the gender. 

“It was a colleague of mine who did the analysis for determining the sex of the individual and he was doing the analysis late in the evening,” she said.

 “He texted me, ‘It’s a girl, it’s a girl,’ like a gender reveal. It was mind blowing.”

Essel said this study is an exciting proof-of-concept for future work, and that she and her colleagues will be trying to extract DNA from other kinds of archeological artifacts, as anything made of teeth, ivory, bone, or antler could have the same potential to preserve the user’s DNA.