Prezygotization

Prezygotization is a term used in some evolutionary biology writings to denote processes or barriers that occur before zygote formation, thereby reducing or preventing fertilization between individuals from different populations or species. In most standard texts, these barriers are categorized as prezygotic isolation mechanisms, of which several types are well established. Some authors treat prezygotization as equivalent to prezygotic isolation, while others reserve the term for the more procedural or mechanistic aspects that occur at or before the fusion of gametes.

Common prezygotic barriers include temporal isolation, where species mate at different times or seasons; ecological or habitat isolation, due to different microhabitats or ranges; behavioral isolation, due to species-specific courtship rituals or signals; mechanical isolation, which involves incompatible reproductive structures; and gametic isolation, where gametes fail to unite despite contact. In plants, prezygotic barriers also include pollen-stigma incompatibility and differences in pollination biology.

Prezygotization contributes to reproductive isolation and can affect gene flow between populations, influencing the course of speciation. It operates alongside postzygotic barriers, such as reduced viability or fertility of hybrids, but differs in its timing relative to zygote formation.

Because the terminology is not uniformly standardized, the exact use of "prezygotization" can vary by author. When encountered, it is best to interpret the term in the context of discussion about barriers that prevent fertilization prior to zygote formation.