A colour-blind girl is rare because she will be born only when:

Question

A colour-blind girl is rare because she will be born only when: (A) Her mother and maternal grandfather were colour blind. (B) Her father and maternal grandfather were colour blind. (C) Her mother is colour blind and father has normal vision. (D) Parents have normal vision but grandparents were colour blind.

Tardigrade Admin · Accepted Answer

Colour blindness is a recessive sex-linked trait in which the eyes fails to distinguish red and green colours. The gene for normal vision is dominant. The genotype of the mother has to be either XC XC or XCX and that of father XCY so that the daughter becomes colour-blind.

Q. A colour-blind girl is rare because she will be born only when:

Her mother and maternal grandfather were colour blind.

Her father and maternal grandfather were colour blind.

Her mother is colour blind and father has normal vision.

Parents have normal vision but grandparents were colour blind.

Colour blindness is a recessive sex-linked trait in which the eyes fails to distinguish red and green colours. The gene for normal vision is dominant. The genotype of the mother has to be either X^C X^C or X^CX and that of father X^CY so that the daughter becomes colour-blind.