Question

Genes of colour blindness in humans are carried by
A. Mother
B. Father
C. Both
D. Abnormal sex

Answer 1

Hint: Colour blindness is a disability due to which a person is not able to differentiate between colours. It causes difficulty in identifying ripe fruit, reading signals of traffic lights etc. This disease is inheritable.

Complete Answer:
To solve this question, we must know about the colour blindness.
- A colour blind person is unable to differentiate between red and green colour. Our retina of the eye contains a colour sensitive pigment called cones which helps in reading colours by sensing the wavelength.
- In the colour blind person the cones get impaired due to which it cannot read colours. Genetics behind colour-blindness
- Colour blindness is X-linked recessive gene disorder. The Female chromosome is represented by (X,X) and the male is represented as (X,Y) as it is a X-linked chromosome, it can happen to both male and female as the X chromosome is present in both the sexes. It is more likely to occur in males when they have recessive x genes.
- The females are less likely to be colour blind as they have 2 X chromosomes, so the defect can be compensated by the dominant X gene. It can only happen in females when the gene combination is double recessive (x,x).

Thus the correct answer is (C).

Additional Information: Non- colour blind females are the carrier of colour blindness and can pass the defect to their offspring.

Note: Colour blindness can also be caused by the physical or chemical damage to the eye or the optic nerve or the part of the brain responsible for colour vision. It is mainly diagnosed by the colour test or genetic testing.