Heterothallism is a condition similar to dioecious plants in which two complementary individuals are required for sexual reproduction but are morphologically different.
In heterothallic fungi, two different individuals contribute their nuclei for zygote formation.
It involves the production of two types of thallus in fungi that can be designated as the + and - type.
Albert Blakeslee first identified heterothallism in the basal lineage of zygomycetes.
This phenomenon can be observed in Saccharomyces cerevisiae, Aspergillus fumigatus, Aspergillus flavus, and Neurospora crassa.