genetic enhancement cisphenotypic phenotype result mutual genetic enhancement PSI-MI cisphenotypic enhancing genetic interaction A phenotype result in which both of two genetic perturbations result in the phenotype in question and do so in the same manner compared to wild type (for example, both genetic perturbations result in an increased quality phenotype, or both genetic perturbations result in a decreased quality phenotype) and the resulting double genetic perturbation results in a phenotype that is more severe than the most severe single genetic perturbation phenotype. Note that this may be an expected result. MI:2401