What is necessary for a daughter to inherit the color-blind trait from her parents?

To inherit the color-blind trait, a daughter needs to receive the gene responsible for color blindness, which is typically linked to the X chromosome. Color blindness is a recessive trait, and since females have two X chromosomes (XX), they can inherit this trait in a couple of ways.

If a father is color-blind (indicating he has the recessive allele on his single X chromosome), he will pass on the color-blind allele to his daughter, as daughters inherit one X chromosome from their fathers. The mother can contribute either an allele for normal vision or the color-blind allele if she is a carrier. However, even if the mother does not carry the trait, if the daughter’s father is color-blind, she will inherit the trait from him.

In summary, for a daughter to inherit the color-blind trait, having a color-blind father is essential since he can contribute the recessive X chromosome with the color-blind allele. Thus, the correct condition for the inheritance of color blindness in daughters remains that their father must be color-blind.