Survivors of the Ice Age Roundworms awoke alive again after more than 40,000 years

Roundworms are amazingly resistant

Researchers have now discovered that samples of so-called permafrost sediment contain nematodes that began to move and eat after thawing. The roundworms were frozen for the last 40,000 years. This sets a record for the longest time that an animal can survive a so-called cryogenic conservation.

Moscow State University scientists have found in their current study that roundworms contained in permafrost are capable of surviving over 40,000 years of cryogenic conservation. The physicians published the results of their study in the English language journal "Doklady Biological Sciences".

The thawing permafrost is a big problem. Researchers now found worms in the permafrost, which began to re-live after more than 40,000 years. (Image: kichigin19 / fotolia.com)

Worms started to live again a few weeks after thawing

The roundworms contained in the permafrost began to move and eat within a few weeks after thawing. In addition to revealing new boundaries of cryogenic preservation, the findings may also be important in preserving our own tissues, the authors say.

More than 300 samples were examined

For their study, Russian biologists excavated more than 300 samples of frozen soil of various ages and locations, and took them back to their laboratory in Moscow for further investigation. Samples taken from remote areas of northeastern Russia contained nematodes from two different genera, which the researchers placed in petri dishes containing a nutrient medium.

The oldest sample was about 42,000 years old

The worms were kept for several weeks at 20 degrees Celsius until they gradually showed first signs of life. Some of the worms belonging to the genus Panagrolaimus were found 30 meters underground, in a former mound that collapsed about 32,000 years ago. Other specimens of the genus Plectus were found in a drill sample at a depth of only about 3.5 meters. The carbon dating was then used to determine the age of the sample, which was approximately 42,000 years, the researchers explain. Contamination of the samples can not be excluded, but the researchers claim that they have followed strict sterility procedures.

The animals were really frozen all the time

These worms are not known to dig deep into permafrost, and seasonal thawing is usually limited to about 80 centimeters. There was also no evidence of possible thawing beyond a depth of 1.5 meters, when the area was about 9,000 years ago, when the warmest temperatures prevailed, explain the physicians. This makes the scientists pretty sure that the worms have really frozen for an incredibly long time.

In the case of bacteria, the revival of old organisms is nothing new

The revival of old organisms is nothing new. In 2000, scientists extracted spores from Bacillus bacteria that were hidden in 250-million-year-old salt crystals. At that time, the specialists succeeded in bringing these bacteria to life.

Further research is needed

Survivability is certainly impressive, but unfortunately we can not apply the life-sustaining tricks of bacteria to our complicated tissues. Now finding animals that can survive frozen tens of thousands of years is a really interesting discovery that should be explored further, say the authors of the study.

Results could drive cryopreservation

Roundworms are known to be robust creatures. Nematodes have been revived in 39-year-old herbarium specimens, but so far nothing has been observed of a similar magnitude. Nearby relatives of roundworms, so-called tardigrades, are also known to survive extreme conditions and to repair damaged DNA. Even in these creatures, a state of conservation has never been observed for so long, which allows survival after freezing. The current tardigrade record is around 30 years old. Learning more about the biochemical mechanisms that nematodes use to limit the damage of ice and prevent the destruction of DNA over the millennia could point the way to better cryopreservation technologies.

Adaptive mechanisms are very interesting for science

Other organisms have been studied that can convert their fluids into ice, such as wood frogs. So maybe someday human tissue could be frozen for transplants. Maybe even the whole body could be frozen and later revived, the experts speculate. The Pleistocene nematodes have some adaptive mechanisms that may be of scientific and practical importance to related fields of science such as cryomedicine, cryobiology, and astrobiology, the scientists explain.

Can the permafrost also release dangerous pathogens??

However, the current find also has a much darker side. There are fears that the melting of permafrost could release pathogens that had already been frozen tens of thousands of years ago. Nematodes are not particularly worrisome, but their survival is evidence that a variety of organisms, from bacteria to animals and plants to fungi, could possibly return after a long absence. What this means for surrounding ecosystems, is not yet in sight, say the researchers. However, it remains to be hoped that Siberia's melting ice releases only harmless worms and not some dangerous pathogens. (As)