A multicellular creature frozen for thousands of years can be “resurrected”! Russian scientists for the first time revived animals with intestines and brains, after 24 thousand years of their stay in suspended animation! These are worms – nematodes and rotifers, which were dug out of the Yakut permafrost, and after defrosting they immediately began … to reproduce actively! Lyubov SHMAKOVA, Senior Researcher at the Soil Cryology Laboratory of the Institute of Physical Chemistry and Biotechnology, Russian Academy of Sciences, told us about the high-profile experiment, which was successfully carried out by specialists from the Institute of Physicochemical and Biological Problems of Soil Science, Russian Academy of Sciences in Pushchino.
The researchers’ work was to study the biota that was preserved in the permafrost. According to Shmakova, they collected soil samples near the Kolyma and Alazeya rivers in Yakutia. Near Kolyma, nematodes from the genera Panagrolaimus and Plectus were recovered from a depth of 3-3.5 meters, and rotifers from the genus Adineta near Alazeya. Both those and others “slept” in the Arctic soils for 24 thousand years, that is, since the late Pleistocene.
“This is not our first experience of finding and reviving ancient organisms,” explains Lyubov Shmakova. – In the laboratory created by geologist David Gilichinsky, we got acquainted with the most ancient creatures – bacteria that were isolated from sediments, with unicellular eukaryotes (amoebae, flagellates, ciliates). We also successfully isolated them from deposits of different ages, several tens of thousands of years.
But nematodes and rotifers are the first multicellular organisms that have lain in the soil for 24 thousand years, which we have been able to revive. Before them, only worms that had lain in the permafrost in 10-year sediments were awakened from suspended animation.
– Tell us how you chose the place where the worms slept with thousands of sleep?
– Near the above-mentioned rivers there is the most ancient permafrost – the 3.5 meters that we dug, this is not the limit. We drilled wells and raised samples of frozen soil from them – core. Right on the field, they loaded it into special refrigerators and transported it in this form to Pushchino, where it was then put into a special core storage.
– How could you find a microscopic, in fact, dead creature in the ground?
“We didn’t look for him: it’s almost impossible. We took a piece of soil, waited for it to thaw out (we made a so-called enrichment culture – a piece of soil in a liquid medium), and then watched through a microscope to see if someone was alive there. I must say right away that we did not identify the very nematode or rotifer that had lain in the ground for tens of thousands of years and cannot say how many there were. So that we could notice that they are there at all, they had to multiply within a week or two, make up a kind of colony. Rotifers, for example, are 200-500 microns (0.2 mm) in size. Therefore, after reproduction of the protomaterial, we caught several of them from the enrichment culture with a pipette and put them aside (sifted into separate clonal cultures) for further study.
All organisms that we brought and that multiplied here after thawing are females. They multiplied by parthenogenetic means, that is, by cloning themselves.
– What can you already say about the Yakut centenarians?
– As I have already said, we failed to isolate the ancient relative of the “daughters” and “granddaughters” that had multiplied already in the laboratory. Maybe she was still alive at the time of reproduction, but she would not have lasted long, since the lifespan of, for example, rotifers is only two weeks. But those who were born from her are her absolute clones, so that by them we can absolutely confidently say that we studied the very ones who lived 24 thousand years ago.
So, first of all, we studied their genome, determined which genus the worms belong to. The rotifers turned out to be relatives of the widespread in nature Adineta worms, but its new species.
We also conducted an additional experiment with them, freezing them again for two weeks, and then defrosting them. It turned out that they have an amazing mechanism that protects their cells from death and makes them capable of repairing.
The further goal of scientists is to understand, thanks to what substances, what wonderful proteins all this becomes possible with rotifers and nematodes. Of course, it is very difficult to transfer their ability to survive in extreme conditions to humans. In any case, this experiment, according to scientists, is the first important step to understand that revival in thousands of years is generally possible not only for bacteria, but also for multicellular creatures.
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