Girl of normal vision whose father was colorblind marries a man of normal vision whose father was also colourblind. The sons of this marriage would be

Step-by-step solution

Color blindness is an X-linked recessive trait. Let X^C be the normal allele and X^c be the colorblind allele. The girl has normal vision but her father was colorblind ( X^c Y ). She must have inherited the X^c chromosome from her father, making her genotype X^C X^c (carrier). The man has normal vision, so his genotype is X^C Y . The fact that his father was colorblind does not affect his genotype, as he inherits the Y chromosome from his father. When they marry ( X^C X^c X^C Y ), the sons inherit the Y chromosome