Sign Epistasis

Sign epistasis is a type of genetic interaction where the effect of one gene modifies the effect of another gene. It is a form of nonlinear gene-gene interaction, in which the outcome of one gene’s effect on a trait is dependent on the presence or absence of another gene. Sign epistasis is important as it can determine how genes interact to give rise to complex traits, such as disease risk and drug response. For example, certain genetic variants may increase the risk of a particular disease when inherited together, which can be explained by sign epistasis. Understanding sign epistasis is essential for predicting the outcome of gene combinations and developing precision medicine.