Practicing Success
Read the given passage and answer the following questions : |
Why are females less likely to be color blind compared to males? |
Females have two X chromosomes, so the normal gene on one X chromosome can suppress the effect of the recessive gene on the other X chromosome. Females have a stronger immune system Females have fewer cone cells in their eyes Females have a different visual cortex |
Females have two X chromosomes, so the normal gene on one X chromosome can suppress the effect of the recessive gene on the other X chromosome. |
The correct answer is Option (1) -Females have two X chromosomes, so the normal gene on one X chromosome can suppress the effect of the recessive gene on the other X chromosome. Colour Blidness 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. |