Question

Are blue eyes a mutation?

Answer 1

Hint: Mutation is the change in the sequence of DNA. Mutations are caused when there are certain mistakes in the cell division like during DNA replication. It can also be caused due to ionizing radiations or exposure to chemicals. Viruses can also bring about mutation.

Complete answer:
Eye colour is a phenotypic character that is determined by polygenes. It can be determined by the pigment present in the iris and also the light scattered by the medium in the stroma of the iris. The pigment in the eye ranges from light brown to black and the pigment melanin is responsible for the colour of the eye.

The inheritance of the colour of the eye is guided by 15 genes. The child can get the eye colour of the mother, father or an intermediate of the two.

The blue colour of the eye contains very little melanin in it. It is the result of a single mutation in the eye several thousand years back. The pigment of the eye cannot scatter blue-green colour. The inheritance of the blue eye is a recessive trait but is controlled by polygenes. This kind of eye is found in northern and eastern Europe. This kind of eye is also seen in central and western Asia, Africa.

Note: Around 8-10% of the population has blue eyes. Blue eyes are rare in mammals. Some cats and dogs have blue eyes. The other colour of the eye includes amber, brown, green, hazel, red, black.