Which of the following statement is FALSE in relation to colour blindness?
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → Colour blindness is an autosome-linked recessive disorder.
Option (1) Colour blindness is an autosome-linked recessive disorder. — False. NCERT calls colour blindness a sex-linked recessive disorder; its genes lie on the X chromosome, not on an autosome.
Option (2) Boys are more likely to be colour blind than girls. — True. Males have one X, so one faulty gene makes them colour blind.
Option (3) A daughter will not normally be colour blind, unless her mother is a carrier and her father is colour blind. — True. A daughter needs two faulty X chromosomes, one from each parent.
Option (4) Colour blind people generally fail to discriminate between red and green colour. — True. A defect in the red or green cones of the eye.
NCERT Extract:
Mendelian Disorders – “… Colour Blidness : It is a sex-linked recessive disorder due to defect in either red or green cone of eye resulting in failure to discriminate between red and green colour. This defect is due to mutation in certain genes present in the X chromosome.”