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Scientists Discover First-Ever Animal That Doesn’t Breathe Oxygen

“Our discovery shows that evolution can go in strange directions.”




(TMU) — Scientists have made a spectacular discovery of an animal that doesn’t need oxygen to survive. The common parasite that largely preys on salmon is called Henneguya salminicola.

A group of scientists led by Dayana Yahalomi of Tel Aviv University in Israel just discovered that a jellyfish-like parasite doesn’t have a mitochondrial genome—making it the first multicellular organism that doesn’t. That means the organism doesn’t breathe; in fact, it lives its life completely free of depending on oxygen.

They have lost their tissue, their nerve cells, their muscles, everything,” Dorothée Huchon, an evolutionary biologist at Israel’s Tel Aviv University and study co-author, told Live Science. “And now we find they have lost their ability to breathe.”

The study was published in the prestigious journal Proceedings of the National Academy of Sciences (PNAS).

The researchers used deep sequencing and fluorescence microscopy to conduct a close study of H. salminicola. They found that it had lost almost all of the nuclear genes involved in transcribing and replicating mitochondria according to Science Alert.

While some single-celled organisms do not require respiration to survive, all multi-celled organisms typically do—except for the H. Salminicola.

Science Alert reports:

Over many, many years, they have basically devolved from a free-living jellyfish ancestor into the much more simple parasite we see today.

They’ve lost most of the original jellyfish genome, but retaining – oddly – a complex structure resembling jellyfish stinging cells. They don’t use these to sting, but to cling to their hosts: an evolutionary adaptation from the free-living jellyfish’s needs to the parasite’s.

The Henneguya salminicola belongs to the same family Myxozoaas as corals, jellyfish and sea anemones making it a cnidarian. The H. salminicola parasite creates cysts in the flesh of salmon known as “milky flesh” or “tapioca” disease, according to a guide published by the Alaska Department of Fish and Game.

It is also worth mentioning that these parasites are harmless to both humans and the fish they infect as far as we currently know. Scientists are confused as to how the organism survives without breathing. However, Huchon speculated to Haaretz that the parasite may be leeching adenosine triphosphate off of its hosts.

Our discovery confirms that adaptation to an anaerobic environment is not unique to single-celled eukaryotes, but has also evolved in a multicellular, parasitic animal,” the researchers wrote.

Hence, H. salminicola provides an opportunity for understanding the evolutionary transition from an aerobic to an exclusive anaerobic metabolism.”

This doesn’t only change our understanding of how life can work here on Earth, it can also have massive implications for the search for extraterrestrial life throughout the universe.

“Our discovery shows that evolution can go in strange directions,” Huchon said.

By Aaron Kesel | Creative Commons |

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