devarshi-dt-logo

Question:

If a colour-blind man marries a woman who is homozygous for normal colour vision, the probability of their son being colour-blind is?

0.75

0.5

1

0

Solution:

Colour-blind man (XcY) and normal woman (XX) can not have a colour-blind son as it is an X-linked recessive trait and is inherited by criss-cross inheritance. To have a colour-blind son, the mother should be a carrier (XcX) or affected (XcXc) so as to pass the affected X chromosome to son.Therefore, the correct answer is 0.