Scientists Discover First Living Creature Without the Need to Breathe

Microscopic parasite Henneguya Salminicola. Photo credit: Stephen D. Atkinson

The most vital resource for any creature’s survival is oxygen. However, scientists have made a groundbreaking discovery supporting evidence that not all living beings need oxygen to exist. The microscopic salmon parasite, known as the Henneguya Salminicola, is the only known animal that does require aerobic respiration. Containing no mitochondrial genome, the species cannot, even if it wanted to, breathe oxygen.

The H. Salminicola is a micrometer-sized parasite that preys on salmon, infecting and consequently causing a condition called “milky flesh” or Tapioca disease. The spores of this parasite take place in the muscle and skin of the salmon, resulting in cysts on the flesh. Residing on the interior of the fish, the species has evolved to survive without oxygen. In order to gain a better understanding of how this creature exists, researchers obtained H. Salminicola samples from two species of Salmon.

H. Salminicola infects the flesh of salmon, causing “Milky Flesh” Disease. photo credit: Extreme Tech

After assessing the samples, scientists discovered that over the course of the parasite’s evolutionary process, it eliminates not only the mitochondrial genome but the entire set of protein genes associated with it. Historical evidence shows every eukaryotic organism contains mitochondria, which is responsible for converting oxygen and food into useable energy for our cells to grow and function. How could such a biological disadvantage such as lacking mitochondria somehow allow for survival?

While further research remains necessary to fully understand how this species survives without oxygen, it is believed that the parasite leeches energy off of its host. This surprising discovery has truly shed light on this class of organisms and will drive scientists to explore the vast and diverse life on this planet.