Question

Of a normal couple, half the sons are haemophiliac while half the daughters are carriers. The gene is located on.

• A. X-chromosome of father
• B. Y-chromosome of father
• C. One X-chromosome of mother
• D. Both the X-chromosomes of mother

Answer 1

The correct option is C One X-chromosome of mother

Haemophilia is a sex-linked disease. Gene of this disease is located on X-chromosome. In the given case where half the sons are haemophilic and half the daughters are carries this possible only when the gene responsible for haemophilia is located on one X-chromosome of mother.

So, the correct answer is 'One X-chromosome of mother'.