Question: Was it a good idea to revive parasitic microoganisms from 46,000-year-old Siberian permafrost? This is important given current parasitic nematodes are not exactly friendly to humans, i.e. in terms of hookworm and filariasis infections, i.e.
However, in this case the team of researchers who collected and revived these prehistoric roundworms,, have assumed they are likely benign - posing little threat to modern humans. This according to a new study published last Thursday in the journal PLOS Genetics.
The study seems to show these parasitic creatures seem to have remained alive by entering a state called cryptobiosis, in which they reduce their metabolism to extremely low levels to withstand extreme (frigid) conditions. Essentially, the worms were frozen in time. Some have speculated this same method may even be used to enable long (interstellar) human space voyages. But that's another story, and how these parasites survived so long remains to be investigated more fully.
According to PLOS Genetics the researchers calculated the age of the nematodes by radiocarbon dating plant material also found in the permafrost. They determined the organisms are members of a previously unknown species, which they’ve dubbed Panagrolaimus kolymaensis, after the Kolyma River near the site the worms were found. According to Philipp Schiffer, a co-author of the study and evolutionary biologist at the University of Cologne in Germany, in an interview with the Washington Post’s Carolyn Y. Johnson :
“We can say that they are alive, because they move, they eat bacteria on the culture plates, and they reproduce,”
Added Thomas Boothby, a molecular biologist at the University of Wyoming who didn’t contribute to the research, to the Wall Street Journal’s Dominique Mosbergen.
“To have a complex and multicellular organism that can shut down and go into this state of suspended animation—for all extents and purposes appear dead... that’s mind-boggling,”
When organisms enter cryptobiosis, their metabolic, reproductive, developmental and repair processes grind to a halt, according to the University of Hawaii at Manoa. Past studies have found examples of organisms surviving for long periods of time in this state.
For example, a Bacillus bacterial spore lived in amber for between 25 million and 40 million years, and a Lotus seed germinated after spending 1,000 to 1,500 years in an ancient lake, per the paper. Previously, the longest a nematode had been recorded to survive in cryptobiosis was just 39 years.
This discovery of the long-frozen nematodes was first outlined in a 2018 study that estimated the worms, found in a fossil arctic gopher burrow, were 42,000 years old, according to Scientific American’s Meghan Bartels. The new work pushes their age back an additional 4,000 years and claims they’re part of a previously unknown species, which typically lives for only one to two months, per the Washington Post account. According to Gregory Copenhaver, a biologist at the University of North Carolina at Chapel Hill who edited it for PLOS Genetics:
“The age over which it survived is one of the shocking things.”
But I tend to agree with Byron Adams, a biologist at Brigham Young University who wasn’t involved in the work. He told Scientific American that he’s not as sure about the parasites’ age given only a proxy marker was used. I.e. the study only confirmed the age of the surrounding plant material, not the worms themselves. Prof. Adams noted:
“The authors haven’t done the work to show that the animals they have recovered are not simply surface contaminants.”
Left unanswered by any of the academic commenters thus far is the advisability of reviving such ancient creatures, even assuming the radiocarbon dating is accurate.
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