Scientists revived a 46,000-year-old microscopic worm from Siberian permafrost. The nematode, officially named Panagrolaimus kolymaensis, was discovered at a depth of 40 meters inside a fossilized burrow of Arctic squirrels. This depth protected it from environmental shifts and severe cold, allowing it to remain frozen in a suspended state since the Ice Age.
Panagrolaimus kolymaensis survived the harsh conditions of the Late Pleistocene Era by entering a suspended state called cryptobiosis, where the biological activities of an organism are completely halted, enabling survival in conditions that are usually lethal. Through cryptobiosis, these worms pulled off their millennia-long hibernation, suspending their vital functions to resist extreme temperatures and hostile conditions for long periods. Cryptobiosis reduces the metabolism of the organism to undetectable levels, essentially hitting the metabolic pause button and preventing the deterioration of its tissues.
Radiocarbon dating confirmed that the soil where the nematode was found was approximately 45,000 to 47,000 years old, indicating that the specimen had been frozen in deep sleep for millennia. After thawing in a laboratory, Panagrolaimus kolymaensis resumed normal activity and began to reproduce asexually. As a triploid organism possessing three copies of each chromosome, it reproduces by parthenogenesis, a process that does not require a male to generate offspring. The ability to reproduce asexually indicates that its cellular structure remained intact for thousands of years.
Genetic analysis revealed that Panagrolaimus kolymaensis shares certain genes with Caenorhabditis elegans, an organism widely used in biological research. Both species produce trehalose, a natural sugar that protects cells from damage caused by freezing and desiccation. Trehalose stabilizes cellular structures and prevents the formation of ice crystals, allowing organisms like Panagrolaimus kolymaensis to reduce their biological processes to practically zero.
Dr. Philipp Schiffer and his team have been investigating how these nematodes managed to survive far beyond their natural lifespan. "No one imagined that this process could continue for thousands of years, 40 thousand years, or even more. It is really amazing that life can resume after such a long time, right at the border between death and life," said Dr. Philip Schaefer, one of the researchers of this project, according to India Defence Review.
Cryptobiosis is not unique to nematodes; other tiny creatures like tardigrades (water bears) and certain brine shrimp can survive in extreme environments using similar biological strategies.
Scientists are studying over 1,000 of the offspring of Panagrolaimus kolymaensis, which share similar survival genes with modern laboratory nematodes.
The article was written with the assistance of a news analysis system.