TMeerkats are perhaps the most well-known of the quasi-indestructible animals, but their incredible resilience is not exclusive. In a June 7 newspaper in Current biology, researchers at the Soil Cryology Lab at the Institute for Physico-Chemical and Biological Problems in Soil Science in Russia document the resuscitation and reproduction of microscopic rotifers from permafrost samples that are, according to radiocarbon dating, 24,000 years old.
Bdeloid rotifers are complex, microscopic animals that live in and near freshwater. Despite being only about half a millimeter tall, they have a brain and a nervous system, and they use their disc-shaped mouthparts to feed on bacteria and algae – food that comes out through their disposable digestive tract and anus.
A) Complete view of a rotifer obtained from permafrost, (B) side view of the organism’s head, (C) frontal view of the rotifer’s mouthparts
SHMAKOVA ET AL., CURRENT BIOLOGY, 2021
Because bdeloid rotifers tend to live in habitats that freeze solid in winter, scientists have long known that in response to extreme conditions they can enter a suspended metabolic state called cryptobiosis. During cryptobiosis, animals shut down the vast majority of their internal systems until they appear almost dead, and yet they can return to normal once the environment becomes more favorable. Researchers are still trying to understand exactly how they do this at the cellular level, and prior to this publication, studies had suggested that about a decade would be the upper limit for rotifers to recover from this condition.
“This is another example of the tremendous capacity rotifers have to endure in extreme environments,” said Kristin Gribble, an unrelated researcher at the Marine Biological Laboratory in Woods Hole, Massachusetts The New York Times. The only other animals known to survive tens of thousands of years of cryopreservation are nematodes (roundworms). The team revived such worms alongside rotifers in the 24,000-year-old permafrost and revived them from 40,000-year-old samples in a study published in 2018. The well-known hardy tardigrade come third with a scant 30 years.
Matthew Cobb, a zoologist at the University of Manchester who was also not involved in the research, relates The guard that the results are particularly interesting because the bdeloid rotifers differ significantly from most other robust micro-animals, as they reproduce asexually through a rare type of cloning called parthenogenesis. “Now we have the opportunity to compare the genome of this group of animals with their modern equivalents. . . . This will shed light on an important biological curiosity and possibly reveal why some animals have given up sex altogether. “