Target Exam

CUET

Subject

Biology

Chapter

Principles of Inheritance and Variation

Question:

Which of the following statement is FALSE in relation to colour blindness?

Options:

Colour blindness is an autosome-linked recessive disorder.

Boys are more likely to be colour blind than girls.

A daughter will not normally be colour blind, unless her mother is a carrier and her father is colour blind.

Colour blind people generally fail to discriminate between red and green colour.

Correct Answer:

Colour blindness is an autosome-linked recessive disorder.

Explanation:

The correct answer is Option (1) → Colour blindness is an autosome-linked recessive disorder.

Color Blindness: 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. It occurs in about 8 per cent of males and only about 0.4 per cent of females. This is because the genes that lead to red-green colour blindness are on the X chromosome. Males have only one X chromosome and females have two. The son of a woman who carries the gene has a 50 per cent chance of being colour blind. The mother is not herself colour blind because the gene is recessive. That means that its effect is suppressed by her matching dominant normal gene. A daughter will not normally be colour blind, unless her mother is a carrier and her father is colour blind.