What is epistasis?

Epistasis refers specifically to the interaction between genes, where the effect of one gene is suppressed or masked by another gene. This phenomenon can significantly influence the phenotype of an organism. For instance, if two genes are involved in determining a specific trait, the presence of a dominant allele at one gene may suppress the expression of alleles at another gene, leading to variations in the observable traits.

Understanding epistasis is crucial in genetics because it demonstrates how complex interactions between multiple genes can shape an organism's characteristics beyond the simple Mendelian inheritance patterns. By recognizing epistasis, scientists can better dissect the genetic basis of traits and diseases, as it adds another layer of regulation to gene expression and phenotypic outcomes.