Question

Queen victoria and some her female descendants showed no bleeding tendency even though they carried the defective gene coding for coagulation factor ix because

O women do not require coagulation factor IX for hemostasis, and therefore the fact that they did not have a normal gene for it was inconsequential.
O women have two copies of the X chromosome, so if a woman carries a defective gene on one, and there is a normal or healthy gene at the corresponding locus on the other X chromosome, there will be no manifestation of disease.
O there is an autosomal gene that will supply the factor needed for hemostasis in women.

Answer 1

Queen Victoria and her female descendants were carriers of the hemophilia gene due to X-linked recessive inheritance, where a healthy gene on one X chromosome compensated for a defective one on the other, preventing the display of hemophilia symptoms.

Step-by-step explanation:

Queen Victoria and some of her female descendants showed no bleeding tendency, even though they carried the defective gene coding for coagulation factor IX, because women have two copies of the X chromosome. If a woman carries a defective gene on one X chromosome and there is a normal or healthy gene at the corresponding locus on the other X chromosome, she does not exhibit the symptoms of hemophilia. This genetic mechanism is a classic example of X-linked recessive inheritance.

Hemophilia is an example of an X-linked disorder where the faulty gene is located on the X chromosome. In females, which typically have two X chromosomes (XX), a functional gene on one of the X chromosomes can often compensate for a defective gene on the other, resulting in a carrier state rather than full expression of the disorder. This is why hemophilia more commonly affects males (XY), who would exhibit symptoms of the disorder if their single X chromosome carries the defective gene.