India contains 1/6 of the world's population, and its population harbors a tremendous amount of genetic diversity. Yet relatively few modern molecular anthropological studies have been done in India. With previous funding, the researchers have conducted extensive molecular analysis of caste populations from South India. These studies have demonstrated that historical processes (i.e., known patterns of mating within and between castes) leave legible imprints on our genes. This encourages further examination of genetic variation to learn more about the histories of human populations. The researchers are now extending analysis to 300 members of India's poorly understood "tribal" populations. These populations are especially interesting because they are thought to be descendants of some of India's earliest inhabitants. By studying these populations, the researchers will learn more about the early prehistory of the Indian subcontinent. Did the original inhabitants of India come from Africa, Australia, or elsewhere? Comparing genetic variation in these populations with that of the caste populations will teach us more about the early history of the castes, which are thought to have been imposed by Indo-European invaders about 3500 years ago. It will be particularly interesting to learn whether the invaders appropriated the upper caste positions for themselves and relegated the existing Dravidian speakers and tribal populations to lower caste positions (preliminary findings support this scenario but are not extensive enough to prove it conclusively). It is especially important to collect and analyze genetic information from tribal populations because, as India becomes increasingly modernized, they are rapidly being lost or assimilated.
