Red-green colour blindness is a sex-linked recessive trait in humans. Two people with normal colour vision have a colour-blind son. What are the genotypes of the parents?
A) XCXC and XCY
B) XcXc and XcY
C) XCXc and XCY
D) XcXc and XCY
E) XCXC and XcY

Question

Quizplus · Accepted Answer

The mother must be a carrier (XCXc) to pass the recessive allele (Xc) to her son, and the father must have normal vision (XCY) to not pass the trait.

Red-Green Colour Blindness Is a Sex-Linked Recessive Trait in Humans