What is the term for the interaction where one gene masks the effect of another?

The term that describes the interaction where one gene masks the effect of another is known as epistasis. This occurs when the expression of one gene (the epistatic gene) suppresses or alters the expression of another gene (the hypostatic gene). For example, in those cases where a gene affects the pigmentation of an organism, if a second gene controls whether or not pigment is produced, the first gene will be epistatic over the second, resulting in no pigment, regardless of the second gene's expression.

This concept is fundamental in genetics as it helps explain the complexities of inheritance patterns beyond simple Mendelian ratios. In contrast, polygenic inheritance refers to traits controlled by multiple genes, linkage disequilibrium describes the non-random association of alleles at different loci, and a dihybrid cross involves studying the inheritance of two separate traits simultaneously. Each of these terms represents different genetic phenomena, distinct from the masking interaction defined by epistasis.