R-matrix analysis and patterns of gene flow in India

An appraisal on the usefulness of R-matrix analysis and the model of Harpen ding and Ward (1982) to study the population structure of Indian population s is made in the light of prevalent marriage patterns, caste structure, and cultural specificity of the region. With the help of available data on the migration histories and geographical backgrounds of marine fishermen on th e east coast of India, and through the historical analysis of marriage patt erns, it is demonstrated that the routine inferences based on the regressio n plots of average geterozygosity versus genetic distance from the centroid may not generally be apt for the Indian situation. Increased heterozygosit y among migrant fishermen seems to have resulted from mating patterns withi n this community rather than from external gene flow. In either case, the g enetic implications are supposedly identical. Nevertheless, when making inf erences regarding local population structure it is important to have detail ed knowledge of mating patterns and the cultural context of the region unde r study.