Principles of Genetics and Breeding

5.1.6. Introgressive hybridization

Closely related fish species often hybridize naturally to produce fertile offspring. These hybrids (F₁)may serve as the bridge between two parental species and help in gene exchange through backcrossing. The fertile hybrids may inter-breed with the parental species. As a result, genetic introgression takes place. This is a form of gene flow between two species mediated through the hybrids and is called introgressive hybridization.