Jurrasic Park taught us an important lesson – ‘Life always finds a way.’ Scientists, however, didn’t believe in the fictional series, or the warning in it, and decided to recreate just that: bringing back organisms from ‘the dead.’ Scientists from Russian have brought back to life tiny ‘zombies’ that were frozen in Arctic permafrost for 24,000 years and produced clones for them in a labratory. The tiny ‘zombies’ are bdelloid rotifers, or wheel animals, so-named for the wheel-like ring of tiny hairs that circle their mouths. Rotifers are multicellular microscopic animals that live in freshwater environments — and they’ve been around for about 50 million years.
In these 50 million years, they’ve learned new methods to adapt and survive (they may just outlast humans.) Researchers had earlier found that that modern rotifers could be frozen at minus 4 degrees Fahrenheit (minus 20 degrees Celsius) and then revived up to 10 years later. Now, scientists have resuscitated rotifers that froze in ancient Siberian permafrost during the latter part of the Pleistocene epoch (2.6 million to about 11,700 years ago). Once thawed, these ancient rotifers began reproducing asexually through parthenogenesis, creating clones that were their genetic duplicates.
The study, which was published in Current Biology, mentioned that the current samples recovered ‘recovered from northeastern Siberian permafrost radiocarbon-dated to ∼24,000 years BP. This constitutes the longest reported case of rotifer survival in a frozen state. We confirmed the finding by identifying rotifer actin gene sequences in a metagenome obtained from the same sample.” By morphological and molecular markers the researchers discovered that the rotifer belongs to the genus Adineta, and aligns with a contemporary Adineta vaga isolate collected in Belgium. Experiments demonstrated that the ancient rotifer withstands slow cooling and freezing (∼1°C min−1) for at least seven days.
Rotifers evolved to use cryptobiosis because most of them live in watery habitats that often freeze or dry up, Stas Malavin, a researcher at the Institute of Physicochemical and Biological Problems in Soil Science in Pushchino, Russia, and lead author of a new study told Live Science.
‘They suspend their metabolism and accumulate certain compounds like chaperone proteins that help them to recover from cryptobiosis when the conditions improve,” Malavin told Live Science in an email. Rotifers also have mechanisms for repairing DNA damage and for protecting their cells against harmful molecules called reactive oxygen species, Malavin explained.
This is not the first time ancient life has been resurrected. In July 2020, scientists successfully revived microbes that had lain dormant at the bottom of the sea since the age of the dinosaurs, allowing the organisms to eat and even multiply after eons in the deep. Their research shed light on the remarkable survival power of some of Earth’s most primitive species, which can exist for tens of millions of years with barely any oxygen or food before springing back to life in the lab.