Russian scientists have resurrected “zombie” worms that had been frozen for 24,000 years in the Arctic.
The microscopic, multicellular animals — called bdelloid rotifers — have inhabited freshwater environments for some 50 million years. Other studies on rotifers have shown that the animals can be revived after 10 years on ice, but a new study published in the journal Current Biology on Monday confirms that these clever creatures have the potential to live on for millions of more years.
The specimens — sometimes called wheel animals for their round, gaping mouths — were dug up from Siberian permafrost that appeared during the latter part of the Pleistocene epoch, which ended about 11,700 years ago.
Researchers have also noted that the recently thawed animals, which reproduce asexually, had no trouble cloning themselves once they were brought back to life.
A report by Live Science has noted that these “zombie” rotifers aren’t the first once-frozen creatures that scientists have thawed and brought back to life. For instance, nematodes — another worm-like species — have been regenerated after as many as 42,000 years locked in permafrost. Ancient plants have also been recovered and cultivated in labs.
The seemingly impossible is possible for some species on Earth thanks to cryptobiosis. Stas Malavin, a researcher at the Institute of Physicochemical and Biological Problems in Soil Science in the Russian town of Pushchino, told Live Science that these animals can “suspend their metabolism and accumulate certain compounds like chaperone proteins that help them to recover from cryptobiosis when the conditions improve.”
The process of resuscitation is simple.
“We put a piece of permafrost into a Petri dish filled with [a] suitable medium and wait until organisms that are alive recover from their dormancy, start moving and multiply,” Malavin said.
While the finding is critical to cryobiology — that is, the study of how organisms live at extremely low temperatures — Malavin points out that we’re a long way from being able to do it as humans.
“The more complex the organism, the trickier it is to preserve it alive frozen,” he assured Live Science readers. “For mammals, it’s not currently possible.”
Image: Michael Plewka