Question

A man and woman have a son who is color-blind, a recessive sex-linked trait carried on the X-chromosome, but neither parent is color-blind. The woman is now pregnant with their second child. Which of the following is true about the second child?

A. A son will be color-blind because the mother is a carrier of the recessive allele.
B. A daughter will be color-blind because the father is a carrier of the recessive allele.
C. A son will be color-blind because the fathers mother must have been a carrier for the recessive allele.
( Answer D will be in comment section)

Answer 1

D. A daughter will not be color-blind because the father is not a carrier of the recessive allele.

Answer 2

4. A man and woman have a son who is color blind, a recessive sex-linked trait carried on the X-chromosome, but neither parent is color blind. The woman is now pregnant with their second child. Which of the following statements is true about the second child?

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D. A daughter will not be color blind because the father is not a carrier of the recessive allele.

(the trait is X-linked, meaning it is only carried on the X chromosome. Females have 2 X's and males only have one. Dad is not color blind, so his only X is normal. Mom is not color blind either, but one of their children is so it means one of her X's is normal and the other carries the mutation for colorblindness. Every son get their X from mom, because they have to get dad's Y to be a male. So 50% of sons from these parents will be normal, and the other 50% will be colorblind. Every daughter has to get their father's X, and in this case, that is a normal X, so all daughters to these parents will have normal vision, although 50% of them will carry the gene for colorblindness on one of their X chromosomes.)

Answer 3

Did I help? if so can you please give me a medal!

thanks

Answer 4

Thanks for the medal DOG!