The phenomenon of the interaction between nonallelic genes at two or more loci resulting in one gene masking the phenotypic expression of another gene, is known as:

Key Points

• Epistasis is the phenomenon where one gene masks the phenotypic expression of another gene at a different locus.
• It involves the interaction between nonallelic genes, meaning genes that are not alleles of each other.
• This interaction can modify the expected phenotypic ratios in genetic crosses.
• Epistasis is different from other genetic interactions like linkage, where genes are located close to each other on the same chromosome.

Additional Information

• Linkage refers to genes located close to each other on the same chromosome that tend to be inherited together.
• Incomplete inheritance (or incomplete dominance) occurs when the phenotype of the heterozygote is intermediate between the phenotypes of the homozygotes.
• Complete inheritance (or complete dominance) occurs when the phenotype of the heterozygote is the same as the phenotype of the dominant homozygote.