Genetic Revelations of a New Paradigm of Plant Domestication As a Landscape Level Process

As genetic and archaeological evidence has developed over the past few years, it has become apparent that our most basic assumptions about how crops became incorporated into human culture may be in need of fundamental revision. Conventionally, crop origins have been understood through a local founding model in which one or multiple centers of small localized populations are formed through cultivation leading to domesticated forms as plants adapt to local human environments either over short, or more recently, longer time frames. However, the genetic expectations of such models are not being met by archaeogenomic and archaeological data. A key concept to the local founder model, the domestication bottleneck, is not supported by several lines of evidence including direct estimates of genetic diversity in the past, mutation load, strength of selection, and the theoretical balance between selection strength and population size. Key to this is the incorporation of models of evolution that are coherent with the development of archaeological thought in terms of conscious and unconscious modes of selection. Together, the data currently point away from a localized origin model and toward a diffuse landscape scale process which occurred over a very long period of time with sustained networks of contact. The domesticated forms that emerged from this process were diverse and consequently more adaptively robust with higher plasticity than would be expected from a local founder model.