enhancement unilateral enhancement 2013-06-05T20:33:13Z An effect in which the phenotype of one genetic perturbation is enhanced by a second perturbation (which, on its own, has no effect on the phenotype in question) to a severity/penetrance beyond (further from wild type) that of the original phenotype. With respect to any single quantifiable phenotype, this may be expressed as an inequality as: ab < a < b = wt [E = a] OR wt = b < a < ab [E = a] where 'a' and 'b' are the observed phenotype values of the individual perturbations, 'ab' is the observed phenotype value of the double perturbation, 'E' is the expected phenotype value of the double perturbation, and 'wt' is the wild type phenotype value. MI:1279 PSI-MI orchard