Question

Hemophilia is a sex-linked disorder. Males who receive the allele are always affected. Females are affected only 25% of the time. Which kind of inheritance must hemophilia display and why? (1 point)

A. Y-linked recessive because the males that receive the allele sometimes have hemophilia.
B. Y-linked dominant because all males with the allele have hemophilia.
C. X-linked recessive because all males with allele have hemophilia, and only some females if they receive two recessive alleles.
D. X-linked dominant because everyone with the allele has hemophilia.

Answer 1

Thank you!

Answer 2

C. X-linked recessive because all males with the allele have hemophilia, and only some females if they receive two recessive alleles.

**Explanation:** Hemophilia is caused by a recessive allele located on the X chromosome. Males have only one X chromosome (XY), so if they inherit the recessive allele, they will express the disorder. Females have two X chromosomes (XX), and for them to be affected, they must inherit two copies of the recessive allele (one from each parent). This is why only some females (25% in this case) are affected if they are carriers of the recessive allele.

Answer 3

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