Socioeconomic covariates and their impact on the opportunity for natural selection in a riparian tribe of Northeast India

The intensity of natural selection correlates with various bio-social variables which influence the genetic structure of a population. In this paper it has been sought to find out the influence of variable environmental setting and economic condition on selection intensity among the Mising tribal population of Assam, Northeast India. Detailed reproductive pattern of 309 post menopausal women is obtained and a comparison has been made between different environmental as well as economic backgrounds. The impact of secular change on selection intensity has been assessed. For this study I have proposed a modified formula of Johnston & Kensinger's (1971) index for selection intensity. Crow's index of selection intensity has also been used for comparative analyses. After considering standard statistical procedure, a clear disparity of selection intensity has been noticed in terms of varying socioeconomic condition as well as habitational background. It can be concluded from the study that environmental factors act more in terms of selection pressure on infants rather than the other post natal stages.