What phenotype do the children of a color-blind woman and a non-color-blind man exhibit?

• A. All will be color-blind
• B. All daughters will be color-blind
• C. All sons will be color-blind
• D. Daughters will be carriers, sons will be unaffected

Answer: (C)

To determine the phenotypes of the children produced by a color-blind woman and a non-color-blind man, it's essential to understand the inheritance pattern of color blindness, which is often linked to the X chromosome. Color blindness is usually a recessive trait carried on the X chromosome; hence, females have two X chromosomes (XX) and males have one X and one Y chromosome (XY).

The color-blind woman must have two copies of the color-blind allele (XᶜXᶜ), as one mutated allele on a single X chromosome would not lead to color blindness in females. The non-color-blind man has one normal allele on his X chromosome and a Y chromosome (XᶠY).

When these parents have children, the possible combinations can be described as follows:

• Daughters will inherit one X chromosome from their mother (Xᶜ) and one from their father (Xᶠ), resulting in the genotype XᶜXᶠ. These daughters will not be color-blind, as they possess one normal allele, meaning they will have normal color vision but be carriers of the color-blind allele.

• Sons will inherit the Y chromosome from their father and one X