Red-green color deficiency is due to a recessive gene on the X chromosome. Women can be carriers or have color deficienty, and men are either color deficient or not. If an unaffected male and a female who is a carrier have children, what is your prediction as to the color deficiency status of their children?
A) Half of the couple's daughters, but none of their sons, are likely to have red-green color deficiency.
B) Half of the couple's sons, but none of their daughters, are likely to have red-green color deficiency.
C) None of the couple's children are likely to have red-green color deficiency.
D) All of the couple's children are likely to have red-green color deficiency.

Question

Quizplus · Accepted Answer

Since the gene for red-green color deficiency is on the X chromosome, and the mother is a carrier (XcX), while the father is unaffected (XY), their sons (XY) have a 50% chance of inheriting the X chromosome with the deficiency from their mother, leading to color deficiency. Daughters (XX) would receive a normal X chromosome from their father, making them carriers if they inherit the affected X from their mother, but they would not express the deficiency themselves.

Red-Green Color Deficiency Is Due to a Recessive Gene on the X