Scientists have sequenced the parasite genome, which turned out to be micromedus

On the left, the spores of Kudoa iwatai, the size of each is 10 microns. On the right - the jellyfish Aurelia aurita, with a dome diameter of 25 cm



Organisms that lead a parasitic lifestyle, as a rule, have a fairly simple structure. The ancestors of such organisms (the same tapeworms) were much more perfect than their "descendants". Recently, scientists sequencing the parasite Kudoa iwatai genome have discovered that it is a microscopic creature, in fact, a micromedus. At the same time, such an organism consists of only a few cells.



Decoding the parasite's genome has shown that the ancestor of this organism is the cutting intestinal cavity (Cnidaria). Representatives of Cnidaria, in addition to jellyfish, are corals and sea anemones.



“This is an amazing case of extreme degeneration of the body of the body,” said a representative of the team of scientists who made the discovery. “At first, we determined that these were intestinal cavities. Now we want to know how they have become what they are now, ”the scientist continues.

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Degeneration affected not only the body of the body, its genome is also significantly simplified, compared to the jellyfish genome. The genome of Kudoa iwatai is 20-40 times smaller than the genome of an ordinary jellyfish. It is generally one of the smallest and simplest genome among animals. The parasite has only 20 million base pairs, while the average representative of the intestinal cavities has more than 300 million base pairs.



Despite the millions of years of the evolutionary process associated with the degeneration of the species, by all indications, it is still a representative of the stinging intestinal cavities. The parasite has a nematocyte (splitting cell) and a corresponding region in the genome. It is worth noting that the described parasite is the culprit of epidemics among the salmonids. Some fisheries are losing huge amounts of money due to epidemics. Outwardly, this is manifested simply - the fish begins to swim in a circle, and continues to swim like this until death. This behavior is due to damage to the nervous system of fish.



According to the scientists who made the discovery, the newly appeared “jellyfish” will be reclassified, and the animal will probably be classified as Cnidaria. Perhaps a detailed study of the body (although it is well studied and so) will clarify the process of degeneration of the animal. Perhaps scientists will even have to change the idea of ​​which organisms can be considered animals. The parasite has almost no signs of an animal, and yet, this species originated from much more complex organisms. At the same time, the process of changing a large organism, with its transformation into a microscopic being, is unique.