46,000-year-old ‘living’ parasite discovered in ice, ‘like the fairy tale of Sleeping Beauty’

Scientists have revived a 46,000-year-old parasite, previously thought to be extinct, that has been “living” in the Siberian permafrost.

Detailed in a study published in PLOS Genetics, scientists found through carbon analysis that the microscopic nematodes, better known as roundworms, dated back to the late Pleistocene era.

“This little worm could now be in line for a Guinness World Record, having remained in a state of suspended animation for far longer than anyone thought was possible,” Professor Teymuras Kurzchalia, senior author of the study, and emeritus professor at the Max Planck Institute of Molecular Cell Biology and Genetics in Germany, told Sky News.

“That it could be reanimated after 46,000 years left me absolutely flabbergasted. It is rather like the fairy tale of Sleeping Beauty, but over a far longer period.”

These creatures have the ability to shut down their systems while in unsuitable environmental conditions through a state called cryptobiosis, meaning they’re in a deep sleep and won’t move or reproduce, and their metabolism stops.

Researcher Anastasia Shatilovich discovered two nematodes in cryptobiosis in the sub-zero temperatures back in 2018, which she took back to the laboratory.

A group of scientists were then able to thaw the prehistoric worms back to life through food and water and get them out of their shut-down state.

“It’s kind of a super fascinating finally to suddenly see life, living animals crawling out of a piece of soil that has been deep frozen for 46,000 years,” Dr. Philipp Schiffer, research group leader at the University of Cologne, told Reuters.

It was formerly thought that roundworms could only maintain a state of cryptobiosis for just under 40 years — but analysis of the plant material the nematodes ate prior to entering cryptobiosis revealed that the nematodes dated to be about 46,000 years old.

The findings “indicate that by adapting to survive cryptobiotic state for short time frames in environments like permafrost, some nematode species gained the potential for individual worms to remain in the state for geological timeframes,” the authors of the study wrote.

Genetic analysis shows that these worms were Panagrolaimus kolymaensis, a species that was previously thought to be extinct.

“Previously, we had shown that nematodes from the Siberian permafrost with morphologies consistent with the genera Panagrolaimus and Plectus could be reanimated thousands of years after they had been frozen,” the scientists wrote in their paper. “Several viable nematode individuals were found in two of the more than 300 studied samples of permafrost deposits spanning different ages and genesis.”

“Our findings demonstrate that nematodes evolved mechanisms potentially allowing them to suspend life over geological time scales,” the authors said.

“We live in times of global change and these animals here they are adapted to very extreme environments so they can completely freeze,” Schiffer explained.

“The whole earth seems to be moving to a more extreme environment. And I think by studying these species, comparing the genomes and see how they adapted to these extreme conditions, we can learn a lot about conservation biology. We can learn things that could inform us to maybe save endangered species and think about protection measures and all these things.”

The outcome is beneficial for researchers to understand the long-term survival of organisms and the human evolution process, as well as a step forward in discovering how to scientifically bring back extinct species.

“These findings have implications for our understanding of evolutionary processes, as generation times may be stretched from days to millennia, and long-term survival of individuals of species can lead to the refoundation of otherwise extinct lineages,” the authors wrote.

Since the thawing, the original two worms scientists have been able to help reproduce 100 generations of the Panagrolaimus kolymaensis species, bringing it back from extinction.