As per a study, A Living Bdelloid Rotifer from 24,000-year fold Arctic Permafrost, published in the scientific journal Current Biology on June 7, 2021, Russian scientists have discovered a microscopic multicellular organism at the Alazeya River, situated in Russia’s region of Yakutia (north-eastern Siberia). The organism, known as ‘bdelloid rotifer’, was found to be in a state of frozen animation, scientifically known as cryptobiosis (a physiological state in which metabolic activity is reduced to an undetectable level without disappearing altogether.) It was found in the samples taken from about 3.5 metres below ground. It was able to reproduce asexually through parthenogenesis (reproduction from an ovum without fertilisation, especially as a normal process in some invertebrates and lower plants) after thawing from its frozen state. The findings were confirmed after identifying rotifer actin gene sequences in a metagenome obtained from the same sample that was dug up. It was found that the bdelloid rotifer could withstand the formation of ice crystals that happens during slow freezing. Through radiocarbon dating process, it was ascertained that the age of the recently discovered bdelloid rotifer specimen was somewhere between 23,960 and 24,485 years.
The study concluded that the bdelloid rotifers have some mechanism through which they are able to shield their cells and organs from harm at significantly low temperatures.
This was an interesting discovery as a previous study had concluded that this organism could only survive in this state for a period of 10 years when frozen at about minus 20-degree Celsius.
There have also been reports of similar other multicellular organisms returning to life after thousands of years, which include a microscopic nematode worm, as well as some plants and mosses.
The study shows that a multicellular organism could be frozen and stored for several thousand years and still return to life.
About Bdelloid Rotifer
The bdelloid rotifers belong to a class of rotifers, which consist of microscopic and near-microscopic animals and are known for their ability to survive extremely low temperatures. It is typically between 150 and 700 mm (micrometre). These organisms are commonly referred to as ‘wheel animals’ or ‘wheel animalcules’. The word ‘rotifer’ is derived from Latin, which means ‘wheel bearer’.
The bdelloid rotifers are commonly found in freshwater habitats and in moist soil across the world. Their habitat includes still water like lakes and flowing water like rivers.
Their main characteristics include parthogenetic reproduction and the ability to survive in dry, harsh environments (low oxygen, starvation, high acidity, years of dehydration, and extreme climatic conditions) by entering a state of desiccation-induced dormancy (through a process called ‘anhydrobiosis’) at any stage of life.
The bdelloid rotifers are also known to be ‘ancient asexuals’ due to their unique asexual history that dates back to over 25 million years ago through fossil evidence.
This is the longest reported case of rotifer survival. This belongs to the genus Adineta and aligns with Adineta vaga collected in Belgium.
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