Biology of the people of Sikkim, India. 2. Colour blindness, ear lobe attachment, mid-phalangeal hair and behavioural traits

14 population groups of Sikkim (India)--Lepchas (2), Bhutias (2), Sherpas, Tamangs, Gurungs, Mangars, Rais, Limboos/Subbas, Pradhans (Newars), Brahmans, Chhetris, Scheduled Castes--have been studied in regard of the intra- and intergroup variability of colour blindness, ear lobe attachment, mid-phalangeal hair and behavioural traits (tongue folding, hand clapsing, arm folding, leg folding, handedness). Some of these variables show a considerable distribution heterogeneity, which is discussed considering history and marriage patterns of these populations. As most of them are highly endogamous one can assume that this heterogeneity is caused by locally acting factors such as drift and/or founder effects, which could be preserved due to as good as lacking gene flow among the populations under study. Beyond that the Sikkim data are compared briefly with those reported for other Indian and Asiatic populations.