Back to article: What’s in a name? How organelles of endosymbiotic origin can be distinguished from endosymbionts
FIGURE 3: Different levels of symbiont-host integration. A symbiosis can start from independent species, or might be obligatory from the beginning, for instance when a symbiont interacts with a new host. In order to become fully sexually integrated, one requisite is that the symbiosis is obligatory for both partners.