Question

Following are the two statements given.

I. If both father and son are colour blind, it is definite that the son inherited the trait from his father.
II. Colour blindness is more common in males than females.

Select the correct alternative.

• A. Both I and II are true
• B. I is true, II is false
• C. I is false, II is true
• D. Both I and II are false

Answer 1

The correct option is C I is false, II is true

Statement I is false as colour blindness is caused by an X-linked recessive mutation. The sons inherit their X chromosome from their mother and not father.
Statement II is true. Colour blindness is a recessive trait. The mutant allele is carried by the X ­chromosome. If males carry just a single copy of mutated allele, they will still be diseased. The same is not true for females. So, colour blindness is more common in males than females.