Question
Biology Question on Principles of Inheritance and Variation
A woman with normal vision, but whose father was colour blind, marries a colour blind man. Suppose that the fourth child of this couple was a boy. This boy
A
may be colourblind or may be of normal vision
B
must be colour blind
C
must have normal colour vision
D
will be partially colour blind since he is heterozygous for the colourblind mutant allele.
Answer
may be colourblind or may be of normal vision
Explanation
Solution
Colourblindness is a recessive sex-linked trait. Since the woman's father was colour blind. She should be carrier of the colour blind gene (XCX). When she marries to colour blind man their progeny could be