PUSHCHINO, Russia — A strange water animal from the time of the mammoths has been brought back to life after being buried in Siberia’s permafrost for 24,000 years. Scientists say the tiny creature, dug out of the subsurface soil in a state of “suspended animation,” has even reproduced.
Known as an Arctic rotifer, it measures less than a millimeter in length or 1/25th of an inch. Despite its microscopic size, it has a complex body that includes a gut and a brain. The breakthrough offers hope of resurrecting prehistoric beasts such as the woolly mammoth, the sabre-toothed cat, and even humans. Discovering the mechanism that protects the cells and organs from disintegration may hold the key to prolonging life.
“The takeaway is that a multicellular organism can be frozen and stored as such for thousands of years and then return back to life–a dream of many fiction writers,” says co-author Dr. Stas Malavin from Russia’s Institute of Physicochemical and Biological Problems in Soil Science in a media release.
Will scientists be able to thaw out frozen humans?
The discovery also opens the door to improving preservation of the cells, tissues, and organs of animals — and specifically mammals. Currently, there are over 350 cryogenically frozen individuals waiting to be raised from the dead.
Thousands more prospective candidates have signed up to have their bodies placed in facilities, which include three in the U.S. and one in Russia. The Arctic rotifer, described in the journal Current Biology, belongs to a group of rotifers known as Bdelloids.
It was among a number of specimens collected from the middle reaches of the Alazeya River in Yakutia, northeastern Siberia. They were more than 11 feet below the surface of the frozen waterway.
“Layers of sediments were frozen relatively quickly after their formation and have never melted,” study authors write in their report.
Some of the best and oldest naturally mummified extinct mammals have been unearthed in this area. They range from prehistoric bison and ponies to woolly rhinos and mammoths.
No more male rotifers?
Rotifers are omnivores that live in freshwater pools. They are too small to be seen by the naked eye and eat any bits of plant or meat that can fit in their mouths. What’s more, they are entirely made up of females. Scientists say the species has gone without sex for 80 million years.
Reproduction is through a “clonal process” called parthenogenesis in which eggs develop into embryos without fertilization. Rotifers are remarkably tough and capable of surviving drying, freezing, starvation, and low oxygen. Now, it has been shown they can also persist for millennia. They are the most advanced lifeform to exhibit a degree of immortality.
“Our report is the hardest proof as of today that multicellular animals could withstand tens of thousands of years in cryptobiosis, the state of almost completely arrested metabolism,” Dr. Malavin adds.
The Soil Cryology Lab in Russia specializes in isolating microscopic organisms from Siberia’s ancient permafrost. It remains below the freezing point all year. To collect samples, his team used a drilling rig in some of the most remote Arctic locations. They’ve previously regenerated single-celled microbes trapped in the ice for thousands of years.
What kept these rotifers alive?
A 30,000-year-old nematode worm has also been revived, as well as mosses and some plants. Adding rotifers, nicknamed “wheel animals,” to the list of living things that last indefinitely beneath the icy landscape is a whole new ball game.
Earlier evidence suggested they survive up to a decade when frozen. Radio-carbon dating showed these animals date back 24,000 years, to when mammoths roamed the Earth. Once thawed, the prehistoric rotifer reproduced by parthenogenesis. To follow the process, the researchers froze and then thawed dozens of rotifers in the lab.
Results show they could withstand the formation of ice crystals that happens during slow freezing. It’s believed they have a system that shields cells and organs from harm at exceedingly low temperatures.
“Of course, the more complex the organism, the trickier it is to preserve it alive frozen and, for mammals, it’s not currently possible,” Dr. Malavin explains. “Yet, moving from a single-celled organism to an organism with a gut and brain, though microscopic, is a big step forward.”
What will scientists bring back to life next?
It’s not yet clear what it takes to survive in ice for even a few years and whether the leap to thousands makes much difference, study authors say. The question requires further study. The researchers are continuing to explore Siberia in search of other organisms capable of such long-term cryo-preservation. Ultimately, they want to learn more about the biological reasons behind the phenomenon.
“Our discovery is of interest not only for evolutionary biology but also for practical purposes of cryobiology and biotechnology,” researchers conclude.
Another team of Russian and South Korean scientists is already planning to resurrect a long-lost breed of horse. They extracted blood from the heart of a 42,000-year-old foal unearthed from Siberian permafrost in 2018. It was in near perfect condition, with muscle tissue, skin, and even tufts of hair. The “Jurassic Park” style project could even pave the way for returning the iconic giant woolly mammoth to the planet.
SWNS writer Mark Waghorn contributed to this report.
