What is epistasis in genetics?

Epistasis refers to a genetic interaction where the expression of one gene is influenced or completely masked by one or more other genes. This means that when examining traits in an organism, the effect of a particular gene can be overridden by the presence of another, thereby altering the expected phenotypic outcomes. For instance, in the case of coat color in certain animals, one gene may determine the color while another gene may affect whether the color is expressed at all.

This concept is crucial in understanding the complexity of inheritance patterns and the ways in which multiple genes can interact to produce specific traits. It highlights that the action of a single gene does not occur in isolation but can be significantly modified by the presence or absence of other genes. This interdependence among genes is a key aspect of genetic studies and helps to explain why traits may not be inherited according to simple Mendelian patterns.

In contrast, the other choices focus on different aspects of genetics that do not describe the epistatic interaction. For example, transcription relates to the process of gene expression and does not involve the interaction of multiple genes, while gene mutations refer to changes in the DNA sequence that may or may not affect phenotype. Lastly, the combination of alleles within a population pertains more