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)
Responses

Y-linked recessive because the males that receive the allele sometimes have hemophilia.
Y-linked recessive because the males that receive the allele sometimes have hemophilia.

Y-linked dominant because all males with the allele have hemophilia.
Y-linked dominant because all males with the allele have hemophilia.

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

X-linked dominant because everyone with the allele has hemophilia.
X-linked dominant because everyone with the allele has hemophilia.

Answer 1

X-linked recessive — males (XY) have only one X so a single recessive allele causes disease; females (XX) must inherit two recessive alleles to be affected, so they are affected much less often.