AP BIOLOGY

Detailed explanation-1: -Males are affected more often than females, because the gene is located on the X chromosome. Hemophilia A. Hemophilia A is a disorder where the blood cannot clot properly due to a deficiency of a clotting factor called Factor VIII.

Detailed explanation-2: -A man who has hemophilia can only pass his altered hemophilia gene on to his daughters, as only his daughters will inherit his altered X chromosome (his sons will inherit his unaffected Y chromosome).

Detailed explanation-3: -However, all daughters of a man with hemophilia are considered obligate carriers of hemophilia because they must receive the affected X chromosome from their fathers to be female, and they can pass the gene to their sons. A female with the hemophilia gene is called a hemophilia carrier.

Detailed explanation-4: -Hemophilia A and hemophilia B are inherited in an X-linked recessive pattern. The genes associated with these conditions are located on the X chromosome, which is one of the two sex chromosomes. In males (who have only one X chromosome), one altered copy of the gene in each cell is sufficient to cause the condition.