ABSTRACT
Archaeologists infer changes in social structure indirectly from the distribution of artifacts in space. But the chain of assumptions required for such inferences can sometimes become tenuous. Genetic markers offer a more direct approach to tracing not only the movement of populations on the landscape, but also patterns of genetic relatedness within communities. Here we utilize non-coding regions of DNA with rapid mutation rates to analyze changes in social structure associated with the historical development of wet-rice farming on the Indonesian island of Bali. We begin by reviewing current debates about irrigation in Bali. Subsequently, we present a model to explain the origins and spread of irrigation systems on Balinese volcanoes. We then test some of the model’s predictions by means of a comparative analysis of genetic relatedness in 21 villages and nine regions of Bali.
