A woman is red-green color-blind. What can we conclude, if anything, about her father?

• A. We have too little information to tell.
• B. There is a 50% probability that he has normal vision.
• C. He has two Y chromosomes.
• D. None of the listed responses is correct.
• E. He is red-green color-blind.

Answer: (E)

Verified step by step guidance

1. Understand that red-green color blindness is a sex-linked recessive trait located on the X chromosome.
2. Recognize that females have two X chromosomes (XX), and for a female to be red-green color-blind, she must have two copies of the recessive allele (one on each X chromosome).
3. Since the woman is red-green color-blind, she must have inherited one recessive allele from each parent.
4. Her father, having only one X chromosome (XY), must have the recessive allele on his X chromosome to pass it to his daughter.
5. Conclude that the father is red-green color-blind because he has the recessive allele on his single X chromosome.