Question

More men suffer from colour blindness than women because

• A. Women are more resistant to disease than men.
• B. The male sex hormone testosterone causes the disease.
• C. The colour blind gene is carried on the 'Y' chromosome.
• D. Men are hemizygous and one defective gene is enough to make them colour blind.

Answer 1

The correct option is D Men are hemizygous and one defective gene is enough to make them colour blind.

It's because men do have an X and Y chromosome and Y chromosome is not capable of carrying any genes. Thus even a single gene is enough to cause inherited disorders in men.