Question

A woman and man have four children. The man is red-green colorblind, but the woman is not. Which of the following combinations of offspring illustrates the most likely phenotypic outcome possible?

• A. 1 colorblind son. 1 son with normal color vision, 1 daughter with normal color vision who is not a carrier for colorblindness, and 1 daughter who is a carrier for colorblindness
• B. 2 sons with normal color vision, and 2 daughters with normal color vision who are carriers for colorblindness
• C. 2 colorblind sons and 2 colorblind daughters
• D. 3 daughters with normal color vision, and 1 son with colorblindness
• E. 2 daughters with colorblindness and 2 sons with colorblindness

Answer 1

Answer: (B)

2 sons with normal color vision, and 2 daughters with normal color vision who are carriers for colorblindness

The cross can be represented as shown in the figure.

Hence the results are as follows:

two sons which have normal color vision (with genotype XY) and two daughters which are carrier for the colorblindness (with genotype X^cX).

So, the correct answer is '2 sons with normal color vision, and 2 daughters with normal color vision who are carriers for colorblindness'.