The phenomenon described in the question is called epistasis. Epistasis occurs when one gene pair masks or hides the effects of another gene pair. This means that the expression of one gene is dependent on the presence or absence of another gene. In epistasis, the gene that masks the other gene is called the epistatic gene, and the gene that is masked is called the hypostatic gene. This interaction can result in complex genetic patterns and can affect the inheritance of traits. It is important to note that mutation refers to changes in DNA sequence and is not directly related to the phenomenon described in the question. Dominance refers to the interaction between different versions of a gene (alleles) at the same genetic locus, but it does not specifically describe the scenario where one gene hides the effect of another.