Tiny animal survives frozen in Siberian permafrost after 24,000 years: “A big step forward”
Much has changed on Earth in the past few decades, but for a recently resurrected microscopic living thing it has tens of thousands of years to catch up.
In a new study published this week in the journal Current Biology, researchers report the surprising survival story of a daisy, a tiny freshwater creature found around the world. The multicellular animals can only be seen under a microscope, but they arefrom dehydration, freezing, hunger and lack of oxygen.
Now researchers have found that these animals are not only resilient, but can also survive extremely long – at least 24,000 years – in Siberia. Previous evidence suggested they could only survive a decade.
“Our report is the hardest evidence to date that multicellular animals could survive tens of thousands of years in cryptobiosis, the state of the almost completely stopped metabolism,” said study author Stas Malavin in a Statement.
The soil cryology laboratory in Pushchino, Russia used an oil rig to collect the tiny organism from nearly a dozen feet below one of the most remote arctic locations. The researchers then inferred his age using radiocarbon dating.
After the organism was thawed, it was able to reproduce asexually through a process called parthenogenesis. Through the dozens of repetitions of freezing and thawing, the researchers found that the animal naturally goes through a process to protect its cells and organs from the formation of ice crystals at extremely low temperatures.
Finding this property in a multicellular organism pushes the limits of what scientists thought possible.
“The real finding is that a multicellular organism as such can be frozen and stored for thousands of years and then brought back to life – a dream for many novelists,” said Malavin. “Of course, the more complex the organism, the more difficult it is to keep it frozen alive, and this is currently not possible for mammals. is a big step forward. “
Rotifers are now joining the list of organisms that can survive underground for seemingly indefinite periods of time, including many unicellular microbes, 30,000-year-old nematodes, mosses, and some plants. Long-dead but still well-preserved mammals have also been found in melting permafrost that are succumbing to climate change, including afrom the Ice Age and an 18,000 year old puppy.
The new findings seem to bring more questions than answers. Scientists are not sure what enables these organisms to survive in the ice for even a few years, and it is even less clear whether the difference between a few years and several thousand is significant.
The researchers hope that further examination of arctic samples will provide new insights into the preservation of cells, tissues and organs of other animals, including humans.