Whether human beings or animals, plants or algae: the cells of most life forms contain special structures that are responsible for energy production. Referred to as mitochondria, they normally have their own genetic material, in addition to that found in the nucleus. Uwe John and colleagues at the Alfred Wegener Institute have now identified the first-ever exception to this rule in a single-celled parasite. The mitochondria of the dinoflagellate Amoebophrya ceratii appear to produce energy just like our own mitochondria, but without any genetic material, as the team reports in the journal Science Advances.