Hydrogenosomes are highly variable organelles that have presumably evolved from protomitochondria to produce molecular hydrogen and ATP in anaerobic conditions.
Because hydrogenosomes hold evolutionary lineage significance for organisms living in anaerobic or oxygen-stressed environments, many research institutions have since documented their findings on how the organelle differs in various sources.
In addition to this seminal study on hydrogenosomes, they also demonstrated for the first time the presence of pyruvate:ferredoxin oxido-reductase and hydrogenase in eukaryotes.
[2] Further studies were subsequently conducted on the biochemical cytology and subcellular organization of several anaerobic protozoan parasites (ex:Trichomonas vaginalis, Tritrichomonas foetus, Giardia lamblia, and Entamoeba sp.).
[5] Hydrogenosomes are organelles that are speculated to have evolved from mitochondria to provide a different mechanism for anaerobic ATP synthesis utilizing pyruvate.