Genetic interactions, in genetics, are interactions that occur between two or more mutations that results in a new phenotype. Studying genetic interactions can reveal gene function, the nature of the mutations, functional redundancy, and protein interactions. Because protein complexes are responsible for most biological functions, genetic interactions are a powerful tool.

Examples of pair-wise interactions:

• Suppression - the double mutant is wild type
• Epistasis - the double mutant is like one of the single mutants
• Synthetic lethality - the double mutant is lethal
• Intragenic complementation - two mutations cause similar phenotypes and map to the same locus yet show complementation in heterozygotes.
• Unlinked non-complementation - two mutations fail to complement but do not map to the same locus