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Principles of Inheritance and Variation

Identify the sex-linked recessive disorder in which clotting of blood is affected.
A. Haemophilia
B. Colour blindness
C. Cystic fibrosis
D. Sickle cell anaemia

A. Haemophilia

It is a sex-linked recessive disorder. Which shows its transmission from unaffected carrier female to some of the male progeny.
Patient continues to bleed even with a minor cut because of a defect in blood coagulation
The gene for haemophilia is located on X-chromosome.
More males suffer from haemophilia than females because in males single gene for the defect is able to express as male have only one X-chromosome.

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