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.

Answer 1

The correct response is:

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

**Explanation:**
Hemophilia is a condition that is typically inherited in an X-linked recessive manner. Males have one X and one Y chromosome (XY), so if they inherit the X chromosome that carries the hemophilia allele, they will express the condition because they do not have a second X chromosome to provide a normal allele. Females have two X chromosomes (XX), so they would need to inherit the hemophilia allele on both X chromosomes to be affected (which occurs 25% of the time in the scenario mentioned). Hence, it confirms that the inheritance pattern is X-linked recessive.