For the first time discovered animals not breathing

The aquatic parasite has no breathing gene because evolution has removed the body parts to make it simpler.

Every multicellular animal on Earth that the scientists have sequenced has genes for breathing, with the exception of Henneguya salminicola , according to research published in the journal Proceedings of the National Academy of Sciences on 24 / 2. They spend all their time attacking the thick muscle tissues of fish and worms in the water, so there is not much chance of turning oxygen into energy.

Photograph of spores of salminicola Henneguya parasite under microscope.(Photo: Live Science).

Genetic analysis and microscopic analysis showed that, unlike all known animals, H. salminicola does not have a mitochondrial genome - a small but important part of the DNA located in an animal's mitochondria, containing the gene is responsible for breathing. This is the first time scientists have found such deficiencies in animals. However, this feature is very suitable for H. salminicola.

Similarly to many parasites of the myxozoa - a group of tiny aquatic parasites, far away from jellyfish - H. salminicola may have looked like jellyfish, but gradually evolved to be different."They have lost tissue, muscle, nerve cells, everything. We now find that they also lose the ability to breathe," said Dorothée Huchon, co-author of the study, evolutionary biologist at Tel Aviv University. , said.

This simplification can benefit parasites like H. salminicola, which grow by reproducing as quickly and as much as possible. Myxozoa owns one of the smallest genomes in the animal world, helping them reproduce effectively. While H. salminicola is relatively "peaceful", other parasites of this group infect and eradicate some fish populations, becoming a threat to both fish and fishermen.

When attacking fish, H. salminicola appears as small white spots on the flesh, looking like unicellular organisms. Only their spores are a bit more complicated. When viewed under a microscope, these spores look like pale blue sperm with two tails and oval "eyes" like aliens.

These eyes are essentially cells to prick, sting, no venom but help parasites cling to the host when needed. These cells are one of the rare features that H. salminicola does not eliminate during evolution.

"People always think of animals as multicellular organisms with lots of genes and evolving to become more and more complex. However, here we have a completely opposite creature. They evolve to become almost unicellular, " Huchon commented.

The team is not clear exactly how H. salminicola gets its energy while not breathing. According to Huchon, some similar parasites possess proteins that can receive ATP (molecular energy) directly from the host. Experts need to study H. salminicola's genome to see if they receive energy in this way.