Why is the frequency of red-green colour blindness is many times higher in males than that in the females?
Colour blindness is common hereditary condition which means it is passed down from parents. Red/green colour blindness is passed from mother to son on the 23rd chromosome, which is known as the sex chromosome. The faulty gene for colour blindness is found only on the X chromosome. When the father is colour blind, he can only pass an X chromosome to his daughter. Thus she acquires the gene and become the carrier of the disease. While a mother who can pass the X chromosome to both son and daughter. For a son to be colour blind, it is enough for his mother to be a carrier. But for a daughter to be colour blind her father should be colour blind and mother who is a carrier of colour blindgene. For a daughter to be a carrier it is enough to get the faulty gene from carrier mother or colour blind father.
Thus males have higher frequency to be colour blind than females.
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