I often spend a lot of my time trying to express myself so that people don't think I'm situating myself in one camp in an either/or argument, because they are by their nature over-simplified typologies. This has happened several times when I attempt to express my opinion about the Indian caste system: a complex confluence of ancient historical legacies (reflected in the genetics) and recent instances of social mobility resulting in a mosaic that is difficult to generalize about. So here is a post about northeast India over at Dienekes blog that ends:

An interesting and important feature that emerges from this analysis is the reflection of the effect of the sociological process of a Tribe-Caste continuum on genetic structure. While on one end we have the cluster of Caucasoid caste populations, the other end consists of Mongoloid tribal groups. In between are the populations which were originally tribes but now have become semi-Hinduized caste groups, viz., Rajbanshi, Chutiya, and Ahom. These groups have currently assumed caste status and speak Indo-European languages.