Scientists accidentally discover first animal that doesn't breathe oxygen

https://www.cnet.com/news/scientists-accidentally-discover-first-animal-that-doesnt-breathe-oxygen/

Jackson Ryan
February 25, 2020 4:01 PM PST

Oxygen, I'm sure you'd agree, is pretty important for life on Earth. We breathe it in, our cells survive on it and without it, we're pretty much doomed. Basically all multicellular life on Earth evolved to utilize oxygen over millions of years.

But take a deep breath because we need to talk about Henneguya salminicola, a tiny parasite containing less than 10 cells that lives within the muscle tissue of salmon. The alien-tadpole-looking parasite does not busy itself with such trifling matters as breathing oxygen. Nope, it seems H. salminicola is the first multicellular animal we've found that survives without the stuff.

"Aerobic respiration was thought to be ubiquitous in animals, but now we confirmed that this is not the case," said Dorothee Huchon, a zoologist at Tel Aviv University in Israel, in a press release.

Huchon and a team of international researchers examined and sequenced all of H. salminicola's genes in their study, published in the journal Proceedings of the National Academy of Sciences on Monday. They found the parasite, which is closely related to jellyfish, lacks the DNA machinery necessary to "breathe" -- it doesn't have a mitochondria. The mitochondria is often called the "powerhouse" of the cell, because it uses oxygen to make energy. It's like a little factory inside (almost) all cells and DNA sleuths can find its genes during sequencing.

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