NEET Biology 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 blindCorrect
(C)Her mother is colour blind and father has normal vision
(D)Parents have normal vision but grandparents were colour blind

Answer: (B)

Solution

Colour blindness is an X-linked recessive trait, so a colour-blind girl must be , receiving one from each parent. She necessarily needs her father to be colour blind () to supply his only X chromosome bearing . For the mother to supply an as well, she must be at least a carrier, which

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Question ID VK-120153