Skip to main content

Epistasis

Meaning

Epistasis describes a complex genetic phenomenon where the phenotypic expression of one gene is significantly modified or masked by the effect of one or more other genes at different loci. This is not merely an additive effect; rather, it represents a non-linear interaction where the combined effect of multiple genetic variants differs from the sum of their individual effects. In hormonal health, epistasis is crucial for understanding why certain individuals with a specific hormone receptor gene variant may exhibit a vastly different clinical outcome depending on the simultaneous presence of a variant in a metabolic enzyme gene. This interaction contributes significantly to the polygenic nature of many endocrine disorders.