Scientists bring back to life worm frozen for 46,000 years

It had survived in a state of cryptobiosis.
Loukia Papadopoulos
The frozen worm.jpg
The frozen worm.

Plos Genetics 

Scientists have brought back to life a worm that was frozen 46,000 years ago in the Siberian permafrost.

The roundworm, of a previously unknown species, was found 131.2 feet (40 meters) below the surface in a dormant state referred to as cryptobiosis, Teymuras Kurzchalia, professor emeritus at the Max Planck Institute of Molecular Cell Biology and Genetics in Dresden and one of the scientists involved in the research, told CNN on Friday.

Organisms in a cryptobiotic state remain in a state “between death and life,” in which their metabolic rates decrease to an undetectable level, Kurzchalia explained, adding that they can thus endure the complete absence of water or oxygen and withstand high temperatures, as well as freezing or extremely salty conditions. 

Halting life

“One can halt life and then start it from the beginning. This a major finding,” he noted.

“To see that the same biochemical pathway is used in a species which is 200, 300 million years away, that’s really striking,” told CNN Philipp Schiffer, research group leader of the Institute of Zoology at the University of Cologne and one of the scientists involved in the study. “It means that some processes in evolution are deeply conserved.”

Schiffer also noted that other revealing insights can be deduced by studying these frozen organisms.

The scientist is convinced that "studying the adaptation of species to such extreme environments by analyzing their genomes will allow us to develop better conservation strategies in the face of global warming,” reported

This isn’t the first frozen worm to be revived. Approximately five years ago, scientists from the Institute of Physicochemical and Biological Problems in Soil Science in Russia found two other roundworm species in the Siberian permafrost.

At the time, researcher Anastasia Shatilovich revived two of the worms at the institute by simply rehydrating them with water. She then proceeded to take around 100 worms to labs in Germany for further analysis, by transporting them in her pocket.

An old species

Radiocarbon analysis of the plant material in the samples indicated that the deposits had not been thawed since between 45,839 and 47,769 years ago, making the worms quite old.

Further genetic analysis conducted by scientists in Dresden and Cologne found that these worms belonged to a novel species, which researchers called Panagrolaimus kolymaenis.

They discovered that the P. kolymaenis species shared with C. elegans “a molecular toolkit” that could allow both organisms to produce a sugar called trehalose that would allow them to survive freezing and dehydration.

The study is published Plos Genetics.

Study abstract:

Some organisms in nature have developed the ability to enter a state of suspended metabolism called cryptobiosis when environmental conditions are unfavorable. This state-transition requires execution of a combination of genetic and biochemical pathways that enable the organism to survive for prolonged periods. Recently, nematode individuals have been reanimated from Siberian permafrost after remaining in cryptobiosis. Preliminary analysis indicates that these nematodes belong to the genera Panagrolaimus and Plectus. Here, we present precise radiocarbon dating indicating that the Panagrolaimus individuals have remained in cryptobiosis since the late Pleistocene (~46,000 years). Phylogenetic inference based on our genome assembly and a detailed morphological analysis demonstrate that they belong to an undescribed species, which we named Panagrolaimus kolymaensis. Comparative genome analysis revealed that the molecular toolkit for cryptobiosis in Pkolymaensis and in Celegans is partly orthologous. We show that biochemical mechanisms employed by these two species to survive desiccation and freezing under laboratory conditions are similar. Our experimental evidence also reveals that Celegans dauer larvae can remain viable for longer periods in suspended animation than previously reported. Altogether, our findings demonstrate that nematodes evolved mechanisms potentially allowing them to suspend life over geological time scales.