Genetics problem: Mom is a carrier of red-green color blindness and Dad is red-green color-blind. What is the chance that their daughter will be a carrier?
A)0%
B)50%
C)75%
D)100%

Question

Quizplus · Accepted Answer

The daughter will inherit an X chromosome from each parent. The mom is a carrier and therefore has one normal X chromosome and one X chromosome with the color blindness gene. The dad is red-green color-blind and only has one X chromosome with the color blindness gene. 
There is a 50% chance that the daughter will receive the mom's normal X chromosome and a 50% chance that she will receive the mom's X chromosome with the color blindness gene. Since the dad only has an X chromosome with the color blindness gene, there is a 100% chance that the daughter will receive his X chromosome with the color blindness gene. 
Therefore, the daughter will either be a carrier (50% chance of inheriting the X chromosome with the color blindness gene from mom) or she will inherit the gene from both parents and be red-green color-blind (50% chance of inheriting the X chromosome with the color blindness gene from both parents).

Genetics Problem: Mom Is a Carrier of Red-Green Color Blindness