It has been found , thanks to a study published in PNAS , that a marine microscopic parasite, the myxozoan Henneguya salminicola , belonging to the higher classification of cnidarians, lacks a mitochondrial genome and, therefore, has lost the capacity for aerobic cellular respiration , based on oxygen .
These creatures live exclusively in aquatic environments, mostly marine.
Henneguya salminicola
This finding is the result of a team of researchers led by Dorothee Huchon , from Tel Aviv University, who published in the journal PNAS that this indicates that aerobic respiration (a hallmark of eukaryotes) is not universal among animals:
Our analyzes suggest that H. salminicola lost not only its mitochondrial genome but also almost all of the nuclear genes involved in the transcription and replication of the mitochondrial genome.
Rather, they identified many genes encoding proteins involved in other mitochondrial pathways and determined that genes involved in aerobic respiration or mitochondrial DNA replication were either absent or only present as pseudogenes.
Our discovery confirms that adaptation to an anaerobic environment is not unique to single-celled eukaryotes, but has also evolved into a multicellular parasitic animal. Thus, H. salminicola provides an opportunity to understand the evolutionary transition from aerobic to exclusive anaerobic metabolism.