Definitions for "Epistasis"
Any non-additive interaction between two or more mutations at different loci, such that their combined effect on a phenotype deviates from the sum of their individual effects.
a type of gene interaction in which the inheritance of one gene affects the phenotypic expression of another gene. This occurs because more than one gene product may be necessary for the development of some characteristics.
The blocking of the effects of one gene by the expression of another, non-allelic gene.