Postzigótico

Postzigótico refers to events or barriers that occur after the formation of a zygote, a fertilized egg. In the context of biology, particularly in evolutionary studies, postzygotic barriers are a key component of reproductive isolation between species. These barriers prevent populations of closely related species from interbreeding and producing fertile offspring, even if mating and fertilization have occurred.

There are several types of postzygotic barriers. Hybrid inviability occurs when the genes of the two species are incompatible, leading to the zygote failing to develop or the offspring dying before reaching reproductive maturity. Hybrid sterility is another common barrier, where the hybrid offspring survives but is unable to reproduce due to chromosomal or genetic differences that prevent proper gamete formation. Finally, hybrid breakdown describes a situation where the first generation of hybrids is fertile, but subsequent generations become increasingly inviable or sterile. These postzygotic mechanisms contribute to the maintenance of distinct species by ensuring that hybridization does not lead to gene flow between diverging lineages. They are a critical factor in speciation, the process by which new biological species arise.