pseudogamétás

Pseudogamy is a form of reproduction found in some plants and animals where fertilization is initiated by the fusion of gametes, but the resulting zygote's development is dependent on external stimuli rather than the genetic contribution of the sperm. In essence, sperm acts as a trigger for development, but its genetic material is not incorporated into the new organism.

This phenomenon can be observed in certain species of fish, such as some strains of Amazon molly (Poecilia formosa), where eggs develop only after being stimulated by sperm from a related but distinct species. The sperm penetrates the egg, but its nucleus degenerates or is expelled, and the egg develops parthenogenetically, meaning it develops from an unfertilized egg.

In plants, pseudogamy is sometimes associated with hybridization or polyploidy. The process can involve the fusion of a normal egg cell with a sperm nucleus that does not contribute to the embryo's genetic makeup. The subsequent development of the endosperm, a nutritive tissue in seeds, often requires this pseudogamous fertilization event. While the embryo develops autonomously from the egg, the endosperm's development is dependent on the paternal genetic contribution, even if it's not fully integrated. This reproductive strategy can be a way to maintain genetic diversity or overcome reproductive isolation barriers in certain lineages.