Question

Haemophilia is more common in males because it is a

• A. recessive character carried by Y-chromo- some
• B. dominant character carried by Y-chromo- some
• C. dominant trait carried by X-chromosome
• D. recessive trait carried by X-chromosome.

Answer 1

Answer: (D)

recessive trait carried by X-chromosome.

Answer 2

Haemophilia is more common in males because it is a recessive trait carried by X-chromosome. Haemophilia A is the most common X-linked genetic disease that prevents normal blood clotting when blood vessels are ruptured. It appears in about in 7000 males. In most of the severe cases, an affected person can bleed to death from a bruise or cut. Haemophilia A is caused by the absence of a protein called antihaemophilic factor of factor VIII that is essential for blood clotting. 359 Principles of Inheritance and Variation