Transgressive segregation

In genetics, transgressive segregation is the formation of extreme phenotypes, or transgressive phenotypes, observed in segregated hybrid populations compared to phenotypes observed in the parental lines. The appearance of these trangressive (extreme) phenotypes can be either positive or negative in terms of fitness. If both parents' favorable alleles come together, it will result in a hybrid having a higher fitness than the two parents. The hybrid species will show more genetic variation and variation in gene expression than their parents. As a result, the hybrid species will have some traits that are transgressive (extreme) in nature. Transgressive segregation can allow a hybrid species to populate different environments/niches in which the parent species do not reside, or compete in the existing environment with the parental species.