Explanation

Haemophilia is a sex-linked character (X-linked recessive trait). It is a rare human blood disorder, in which, blood clotting is deficient, resulting in severe bleeding internally and externally. The condition is due to lack of fibrin in the blood and is controlled by two closely linked genes on the blood and is controlled by two closely linked genes on the X-chromosome that are responsible for the production of different clotting factors.