Skin colour in north Indian populations

The skin colour of six endogamous groups of north India has been studied reflectometrically. The percentage reflectance at upper arm and forchead of 650 adult males (20–25 years) is described and discussed using 601 (425 nm), 605 (545 nm) and 609 (685 nm) filters of the “EEL” spectrophotometer. The inter-group heterogeneity is revealed by variance-ratio test. The t-test has been applied to study inter-group differences in pigmentation. Some correspondence has been found in skin colour with caste hierarchy, which holds only when the populations living in the same region are compared. These differences are assigned to adaptive adjustments superimposed by caste endogamy and assortative mating for skin colour.