(adj. heterothallic) condition in which sexual reproduction can occur only in the presence of genetically different mycelia (see homothallism)

A condition of self-sterility imposed by mating-type differences. There are two mating types in Neurospora, and , and mating and completion of the sexual cycle require that parents be of opposite types.

Sexual cycle in dinoflagellates which involves opposite mating types; e.g. Gymnodinium catenatum.