Question

If a female is homozygous recessive for an X-linked, recessive trait, then what percentage of her sons will exhibit this recessive trait? Second, what if she is heterozygous, i.e., she is a carrier, for the same X-linked, recessive trait?

Group of answer choices

the males will exhibit a 3:1 ratio of dominant-to-recessive phenotypes, the males will exhibit a 3:1 ratio of recessive-to-dominant phenotypes

50%, 50%

100%, 100%

the males will exhibit a 3:1 ratio of recessive-to-dominant phenotypes, the males will exhibit a 3:1 ratio of dominant-to-recessive phenotypes

100%, 50%

50%, 100%

Answer 1

Answer: 100%, 50%

In the case of male offsprings(son), they get their Y chromosome from father and X chromosome from mother.

If the mother(Female) is homozygous i.e. both of her X chromosomes have X linked recessive trait so if the son get any of the X chromosomes he will exhibit the X linked recessive trait. 100% of the sons will exhibit it.

If the female is heterozygous for X linked recessive trait that means only one X chromosome will have that recessive trait that means only one of every two sons will exhibit the trait i.e. 50% of them will exhibit it.