Fig. 9.

Diagram illustrating the differences in the timing and location of nuclear division and daughter formation associated with asexual development within the Apicomplexa. There are four distinct processes: (a) “Classical” schizogony undergone by the majority of apicomplexans, including the genera Plasmodium and Eimeria, where there is a proliferative phase with repeated nuclear divisions followed by a differentiation phase with daughter formation initiated at and budding from the parasite plasmalemma. (b) Endodyogeny in which there is no proliferative phase, but one cycle of DNA replication with the initiation of the formation of two daughters within the mother cell cytoplasm prior to the completion of nuclear division. (c) “Toxoplasma” endopolygeny, used to describe the asexual division of Toxoplasma gondii in the definitive host, involves a proliferative phase with repeated nuclear division, similar to “classical” schizogony, but differs in that daughter formation is initiated within the cytoplasm in a similar manner to endodyogeny. (d) “Sarcocystis” endopolygeny has been reported for certain Sarcocystis species and involves an initial phase with repeated cycles of DNA replication and formation of numerous nuclear spindles, but no division of the nucleus. Formation of multiple daughters is initiated within the cytoplasm and the large polyploidy nucleus fragments and one haploid nucleus enters each developing daughter. In the diagram, centrioles are represented by green circles, apicoplasts by red structures and nuclear poles by black triangles.