Agricultural origins: the evidence of modern and ancient DNA

The appearance of agriculture is one of the most striking features of Holocene human history, a feature that has long been studied in an interdisciplinary fashion, bringing archaeology together with plant and animal genetics. This paper reviews new developments in that study, consequent upon recent advances in DNA science. Among these advances is the possibility of complementing modern DNA data with fragmentary evidence of ancient DNA. Following a short account of the historical foundations of this research, studies of plant and animal domesticates based upon variations in protein, modern DNA and ancient DNA are reviewed in turn. The results of these studies are considered against a background of two contrasting models of how agriculture originated and spread, characterized by Blumler (1992) as 'stimulus-diffusion' and 'independent invention'. We argue that existing evidence from DNA supports neither model in its extreme form, favouring instead an intermediate model.