Scientists thawed bdelloid rotifers found in the permafrost of Siberia. They were very surprised, because the organisms were not only alive, but also capable of reproduction. Bdelloid rotifers are tiny multicellular organisms that live in fresh water.
They would be unremarkable if not for their outstanding vitality: they do not care about drought, freezing, lack of food and even oxygen. In unfavorable environmental conditions, rotifers simply roll up into a ball and slow down all vital processes to a minimum in anticipation of better times.
An interesting fact is that females reproduce themselves, and males directly do not even exist in nature.
Rotifers not only came to life after a long sleep: they quickly started feeding and reproducing.
“Our study is the most convincing proof to date that multicellular organisms can withstand tens of thousands of years of cryptobiosis. This is a state in which metabolism practically stops,” explains co-author Stas Malyavin of the Institute of Physical Chemistry and Biology, Russian Academy of Sciences.
It has previously been shown that rotifers can survive after 10 years of freezing. However, now this record has been undoubtedly broken. Radiocarbon analysis of a soil sample in which persistent creatures were found indicated its approximate age – 24 thousand years.
The researchers additionally made sure that they found truly ancient rotifers. Their genetic material was markedly different from the DNA of modern animals.
After randomly selecting 144 “resurrected” multicellular organisms, the scientists froze them again at -15 ° C. The ancient rotifers were able to survive again, although they turned out to be slightly more frost-resistant than their modern relatives.
The authors of the work suggest that with a sufficiently slow freezing, the rotifer organism can withstand the formation of ice crystals in the tissues without any significant losses. However, scientists have yet to understand what allows them to return to life after several tens of millennia of being in this state.
By the way, it is not the first time that the staff of the Soil Cryology Laboratory have “revived” microorganisms found in permafrost. Several years ago, they managed to bring back to life the nematode worms that “slept” for at least 30 thousand years.
The researchers also found and thawed ancient plants and fungi. However, the ability of multicellular animals to withstand such a long freeze, of course, intrigues scientists much more.
“The conclusion is that a multicellular organism can be frozen, preserved for thousands of years in this state and then brought back to life. This is the dream of many science fiction writers. Of course, the more complex an organism, the more difficult it is to keep it alive in a frozen state. this is an impossible task for mammals. However, the transition from single-celled organisms to organisms with intestines and brains, albeit microscopic, is already a big step forward,” Malyavin noted.