Can genetics help us understand Indian social history?

Attempts have been made recently to determine the identity of the so-called "Aryans" as components of the Indian population by using DNA analysis. This is largely to ascertain whether they were indigenous to India or were foreign arrivals. Similar attempts have been made to trace the origins of caste groups on the basis of varna identities and record their distribution. The results so far have been contradictory and, therefore, not of much help to social historians. There are problems in the defining of categories and the techniques of analysis. Aryan is a linguistic and cultural category and not a biological one. Caste groups have no well-defined and invariable boundaries despite marriage codes. Various other categories have been assimilated into particular castes as part of the evolution of social history on the subcontinent. A few examples of these are discussed. The problems with using DNA analysis are also touched on.