Question

Explain why generally only the male child suffers from colour blindness and not the female?

Answer 1

• Colour-blindness is caused due to recessive genes which occur on the X chromosome.
• Males have only one X chromosome. If there is recessive gene present on X chromosome, then the male will suffer from colour-blindness.
• Females have two X chromosomes. It is highly impossible that both the X chromosomes carry abnormal gene. Hence, if one gene is abnormal and since it is recessive, its expression will be masked by the normal gene present on the other X chromosome. Females are unlikely to suffer from colour-blindness.