Interpreting the demic diffusion of early farming in Europe with a three-population model

Abstract

In 1971, Ammerman and Cavalli-Sforza demonstrated that reaction-diffusion equations could be usefully applied to the archaeological question of the spread of early farming in Europe. Their basic premise was demic diffusion, i.e., the iterative short-range colonization of virgin land by the descendants of the original Near Eastern farmers. This hypothesis has been vindicated by ancient DNA studies, which show limited acculturation of the autochthonous hunter-gatherers, who when converted to farming were apparently assimilated into preexisting farming communities. In this brief report, I describe a reaction-diffusion model incorporating various interactions among the Near Eastern farmers, converted farmers, and hunter-gatherers. Predictions, derived in terms of the model parameters, are examined vis-à-vis the ancient DNA and archaeological evidence. Of particular interest is the theoretical requirement that the hunter-gatherers behaved more competitively toward the converted farmers than the Near Eastern (specifically Anatolian) famers. Based on “Ammerman AJ, Cavalli-Sforza LL. Measuring the rate of spread of early farming in Europe. Man 1971; 6: 674-688.”