Incidence of red-green colour blindness in some populations of Delhi, Maharashtra and West Bengal: an examination of the selection relaxation hypothesis

The term colour blindness is generally used to describe the lack of sensitivity to colours. Although there are instances of total colour blindness, in most cases the people confuse red or green, and this defect is an X-linked trait. This colour vision anomaly is widely used as a genetic marker in the study of human variation, and is frequently cited as 'relaxed selection' according to the Post (1962) and Pickford (1963) hypothesis