A recessive allele on the X chromosome is responsible for red-green color blindness in humans.A woman with normal vision whose father is color blind marries a color-blind male.What is the probability that this couple's first son will be color blind?

Question

Quizplus · Accepted Answer

The woman is a carrier of the color blindness allele because she has a normal vision. Her father, who is color blind, can only pass on the recessive allele for color blindness to his daughter. The male is color-blind, which means he has two copies of the recessive allele. The Punnett square for the cross is as follows: | | X^N | X^n | | - | - | - | | Y | XY | X_nY | | Y | XY | X_nY | where X^N and X^n represent the normal and color blindness alleles, respectively. 50% of the male offspring will inherit the X^n allele from the mother and the Y chromosome from the father, resulting in color blindness. Therefore, the answer is B) 50%.

A Recessive Allele on the X Chromosome Is Responsible for Red-Green