Hemophilia A is an X-linked recessive genetic condition.In humans it is due to a mutation in the F8 gene,which encodes a protein called coagulation factor VII.Coagulation factors are proteins important in blood clotting.Individuals with hemophilia,when injured,bleed longer than a normal,healthy individual;the inability to normally clot blood can be life threatening.Which of the following statements is NOT a reason why hemophilia is much more common in males than in females?
A)A female with one defective allele makes enough normal coagulation factor VII to clot blood and will not have hemophilia A
B)Males are hemizygous for the F8 gene,so they will have hemophilia A if they have one defective allele
C)Females have to receive a defective allele from both their mother and their father to get hemophilia A
D)Males have to receive a defective allele only from their father to get hemophilia A

Question

Quizplus · Accepted Answer

Males inherit the X chromosome from their mother and the Y chromosome from their father. Therefore, a male cannot inherit an X-linked allele from his father, making statement D incorrect.

Hemophilia a Is an X-Linked Recessive Genetic Condition