Epistasis means?

Epistasis means?

• A. Two or more genes located on the same chromosome
• B. A single gene determines a phenotype
• C. Two or more genes determine a single phenotype
• D. Genes are inherited independently of each other

Answer: (C)

Epistasis is when two or more genes at different locations interact to produce a single phenotype. The visible trait depends on the combination of alleles across those genes, and one gene’s effect can be masked or modified by another gene. This is why a trait can be controlled by several genes working together, not just by a single gene. For example, in some cases pigment production and pigment deposition are controlled by different genes. If the deposition gene isn’t functioning, no pigment shows up even if the color gene could produce pigment. That kind of interaction—multiple genes shaping one trait—is epistasis. The other ideas describe different concepts: two or more genes on the same chromosome refers to linkage, a single gene determining a phenotype is classic Mendelian single-gene inheritance, and genes inherited independently refers to independent assortment. None of those capture the idea that multiple genes at different loci combine to determine one phenotype.

Epistasis is when two or more genes at different locations interact to produce a single phenotype. The visible trait depends on the combination of alleles across those genes, and one gene’s effect can be masked or modified by another gene. This is why a trait can be controlled by several genes working together, not just by a single gene.

For example, in some cases pigment production and pigment deposition are controlled by different genes. If the deposition gene isn’t functioning, no pigment shows up even if the color gene could produce pigment. That kind of interaction—multiple genes shaping one trait—is epistasis.

The other ideas describe different concepts: two or more genes on the same chromosome refers to linkage, a single gene determining a phenotype is classic Mendelian single-gene inheritance, and genes inherited independently refers to independent assortment. None of those capture the idea that multiple genes at different loci combine to determine one phenotype.