Question

Color blindness is a recessive trait on the X chromosome. What are the genotype and phenotype ratios of a cross between a normal female who is not a carrier and a color-blind male?

Answer 1

if we cross XNXN(normal, non-carrier female) with XnY(color-blind male)

we get XNXn XNY XNXn and XNY

genotype ratio:  XNXn:2   XNY:2

phenotype ratio:2 carrier females and 2 healthy males