Odontometry and biological affinity in south Asia: analysis of three ethnic groups from northwest India

Current knowledge of odontometric variation among the people of south Asia is limited, yet variation in tooth size has the potential to answer important questions regarding genetic relationships among contemporary social groups. Here, we report tooth crown diameters for 3 ethnic groups (Bhils, Garasias, Rajputs) from Gujarat State and contrast these data with 10 social groups from north, northwestern, northeastern, west-central, and south India. Univariate descriptive and inferential statistics are presented by group and by sex. Examination of crown diameters demonstrates that tooth size differs significantly between social groups in Gujarat. Cluster analysis of sex-standardized odontometric mean parameter values indicates that in apportionment of tooth size throughout the dentition low-status Garasias are slightly more similar to tribal Bhils than they are to high-status Rajputs. Principal components analysis by sex identifies three components that together account for 58.2% and 56.3% of the total variance among Gujarati females and males, respectively. These components are identified as overall size, a dimensional contrast between mesiodistal diameters and buccolingual diameters, and a dimensional contrast between mesiodistal diameters and buccolingual diameters among anterior teeth coupled with a contrast between anterior teeth (incisors, canines) and posterior teeth (premolars, molars). Ordination of group component scores indicates that (1) males and females of each social group exhibit a pattern of tooth size apportionment most similar to the opposite member of that same social group and (2) low-status Garasias exhibit a tooth size apportionment profile intermediate between tribal Bhils and high-status Rajputs. To place this pattern of odontometric variation among modern Gujaratis in larger perspective, data from Gujarati males were contrasted against males from 10 social groups from north, northwestern, northeastern, west-central, and south India. Cluster analysis of group-standardized odontometric mean parameter values indicates that (1) Gujarati social groups, regardless of social status or caste adherence, are more similar to one another than to any other group included in this analysis and (2) Gujarati social groups share closet affinities with geographically proximate social groups (Ahirs, Jats, Kunbis). Principal components analysis yields three components that combine to explain 64.0% of the total variance. These components are interpreted as a dimensional contrast among posterior teeth, a dimensional contrast among nonmolar teeth, and a contrast between anterior and posterior teeth. Ordination of group component scores indicates that tribal Bhils possess tooth size apportionment profiles that are different from other Indian tribal groups but are proximate to those found among Gujarati Hindu groups.(ABSTRACT TRUNCATED AT 400 WORDS)