microscopic frozen animals brought back to life after 24,000 years | Biology
Microscopic multicellular animals called bdelloid rotifers are known for their ability to survive extremely low temperatures. They would have survived 6 to 10 years when frozen between minus 20 and 0 degrees Celsius. Today, an international team of biologists has successfully revived bdelloid rotifers frozen in Siberian permafrost for 24,000 years.
In permanently frozen natural habitats, some organisms can be preserved for hundreds to tens of thousands of years.
For example, stalks of Antarctic moss have successfully regrown from a sample over a millennium old covered in ice for about 400 years.
Likewise, whole campion plants were regenerated from seed tissues preserved in a 32,000-year-old relict permafrost, and nematodes were resuscitated from the permafrost of two localities in northeastern Siberia, with sediment sources dating back more than 30,000 years.
“Our report is the strongest evidence to date that multicellular animals called bdelloid rotifers could withstand tens of thousands of years in cryptobiosis, the almost completely stopped metabolic state,” said researcher Dr. Stas Malavin. at the Institute of Physico-Chemistry and Biology. Problems in soil science.
Dr Malavin and his colleagues used radiocarbon dating to determine that the rotifers they recovered from Siberian permafrost were around 24,000 years old.
The microscopic animals belonged to the genus Adineta, and aligned with contemporary species Adineta vaga collected in Belgium.
Once thawed, the rotifers were able to reproduce in a clonal process called parthenogenesis.
To track the process of freezing and retrieving ancient creatures, researchers frozen and then thawed dozens of rotifers in the lab.
Studies have shown that rotifers can resist the formation of ice crystals that occurs during slow freezing.
This suggests that they have a mechanism to protect their cells and organs from damage at extremely low temperatures.
“The bottom line is that a multicellular organism can be frozen and stored as such for thousands of years and then come back to life – a dream of many writers of fiction,” said Dr Malavin.
“Of course, the more complex the organism, the more difficult it is to keep it alive frozen and, for mammals, this is not currently possible.”
“Yet to go from a single-celled organism to an organism with a gut and a brain, although microscopic, is a big step forward.”
“It’s not yet clear what it takes to survive on the ice for even a few years and if jumping to the thousands makes a big difference. This is a question that requires further study.
The team’s article appeared in the June 7, 2021 issue of the journal Current biology.
Lyubov Shmakova et al. 2021. A living bdelloid rotifer from a 24,000-year-old arctic permafrost. Current biology 31 (11): R712-R713; doi: 10.1016 / j.cub.2021.04.077