National Academy of Sciences

In a study published in the journal of PNAS, Proceedings of the National Academy of Sciences, scientists described their findings of a jellyfish-like parasite without oxygen dependency, called Henneguya salminicola. The microscopic parasite has less than 10 cells and has been found to live in salmon muscles. This discovery has changed the assumption that multicellular organisms need a mitochondrial genome to live. The paper further states that "H. salminicola provides an opportunity for understanding the evolutionary transition from an aerobic to an exclusive anaerobic metabolism".