Question

Color blindness is an X-linked recessive trait. A color-blind man has a daughter with normal color vision. She mates with a male who has normal color vision. What is the expected phenotypic ratio of their offspring?

A. 1:1 color-blind to normal color vision
B. 2:1 normal color vision to color-blind
C. 3:1 normal color vision to color-blind
D. 4:0 normal color vision to color-blind

Answer 1

The expected phenotypic ratio of the offspring is 2:1 normal color vision to color-blind.

Step-by-step explanation:

The expected phenotypic ratio of the offspring is 2:1 normal color vision to color-blind. This is because color blindness is an X-linked recessive trait. The daughter of the color-blind man and the female with normal color vision is a carrier for color blindness. When she mates with a male with normal color vision, there is a 50% chance that their son will be color-blind.