Genetic structure of a tribal population: anthropometric differences between regions and settlements among the Yanadi

Microevolutionary changes in morphology were investigated in a transient tribal population who are fast changing from a hunting-gathering to an agricultural stage. Anthropometric data on 14 measurements collected from the Yanadi, who inhabit different geographical regions and differ in their subsistence and other associated cultural traits, demonstrate high morphologic differentiation between two levels of organization: (1) 12 settlements and (2) five regional breeding populations formed by grouping some of the former. The morphologic distances based on Mahalanobis D2 and the dendrograms show wide differences between sexes, in the case of the breeding populations, which can be associated with patterns of marital migration and of spatial distances. In the case of settlements the pattern shows a poor association with geography. Of three spatial distances viz. map, road and geographical barrier index, road distance produces a larger influence on the morphological differentiation within the tribe.