Question

The gene of haemophilia is located on the ‘X’ chromosome. Hence, it is normally impossible for
A. Haemophilic father to pass the gene to his daughter.
B. Carrier mother to pass the gene to her daughter.
C. Carrier mothers to pass the gene to her son.
D. Haemophilic father to pass the gene to his son.

Answer 1

Haemophilia is the most inherited genetic disorder that affects the body’s ability to make blood clots which is a process that helps to stop bleeding. This disorder affects the people to bleed for a long time after a minor injury, increases the risk of bleeding in the joints and brain, and easy bruising.

Step by step answer: There are two major types of haemophilia which are haemophilia A, which occurs due to a low amount of clotting factor VIII, and haemophilia B, which occurs as a result of low levels of clotting factor IX. These types of haemophilia are inherited from the parents through an X chromosome that carries a nonfunctional gene.
Haemophilia is an X chromosome-linked recessive disorder in which people do not produce clotting factors. The mother has an XX chromosome in which one X is normal and the other one is affected. When she inherits one affected X chromosome, she compensates with another normal X chromosome and thus is called a carrier. But a haemophilic father has XY chromosome and none of his sons will be affected as he carries only the Y chromosome from his father.
Hence, the correct option is D, i.e., Haemophilic father to pass the gene to his son.

Note: It is impossible for a father to pass affected chromosome to his son but he can pass affected chromosome to his daughter as she will take one chromosome from her father and another one from mother. If her father has an affected chromosome she will acquire the same.