When the parasitic blob known as Henneguya salminicola sinks its spores into the flesh of a tasty fish, it does not hold its breath. That’s because H. salminicola is the only known animal on Earth that does not breathe.
If you spent your entire life infecting the dense muscle tissues of fish and underwater worms, like H. salminicola does, you probably wouldn’t have much opportunity to turn oxygen into energy, either. However, all other multicellular animals on Earth whose DNA scientists have had a chance to sequence have some respiratory genes. According to a new study published today (Feb. 24) in the journal Proceedings of the National Academy of Sciences, H. salminicola’s genome does not.
A microscopic and genomic analysis of the creature revealed that, unlike all other known animals, H. salminicola has no mitochondrial genome — the small but crucial portion of DNA stored in an animal’s mitochondria that includes genes responsible for respiration.