There are many hues of colors but sometimes few people are unable to differentiate between various colors. Such persons are called as color blind and the condition is called as color blindness. It is observed that color blindness is more common with men as compared to women. Approximately 10 million American men are reported to be color blind but there are only 0.4% of affected women.
The major question arises in our mind is: Why males are more affected by color blindness? Before answering the question let us briefly discuss the factors responsible for a normal color vision and color blindness. Human eye contains 2 types of photoreceptors: Rods and Cones. Now, the Rods are usually active during low light levels whereas the Cones are active during the high light levels. The normal color vision is attained with the help of three types of cones: blue cones, green cones and the red cones. As their names suggest they are sensitive to blue, green and red light respectively. Opsin is a light absorbing pigment which determines the light sensitivity of a particular cone.
When a mutation occurs in genes responsible for the production of opsin it results in color blindness. This mutated gene obstructs the cones to detect the colored light in a normal way. Hence mutation that influences the normal functioning of the light absorbing property of the cones results into color blindness. The genes for the opsin pigment molecules are located on the X chromosome. To be very specific the genes responsible for green and red cone pigment are located on the X chromosome.
After understanding the main cause for color blindness let us answer the question now. Usually females have a pair of X chromosome whereas in case of males they only have 1 X chromosome. The chances of getting original copy of red and green pigment genes are only 1. If by chance the opsin gene is mutated then the male would become color blind. In case of females even if mutation has occurred in one set of gene there is another copy of original gene. And the probability of mutation occurring on both the set of genes is negligible hence the chances of women being color blind is also negligible. So we could conclude that chances of male being color blind is more as compared to females.
