Emerging evidence of plant domestication as a landscape-level process

The evidence from ancient crops over the past decade challenges some of our most basic assumptions about the process of domestication. The emergence of crops has been viewed as a technologically progressive process in which single or multiple localized populations adapt to human environments in response to cultivation. By contrast, new genetic and archaeological evidence reveals a slow process that involved large populations over wide areas with unexpectedly sustained cultural connections in deep time. We review evidence that calls for a new landscape framework of crop origins. Evolutionary processes operate across vast distances of landscape and time, and the origins of domesticates are complex. The domestication bottleneck is a redundant concept and the progressive nature of domestication is in doubt. Current theories of plant domestication are based on localized founder models in which single or multiple domestications occur as a progressive result of adaptation processes, but anomalies that do not fit within this perspective have been accumulating.We describe developments in archaeology and genetics over the past decade in which cultural connections between groups stretch back much further in time than was previously realized, and over wide geographic distances. Weak selection for domestication substantially pre-dates domestication and/or cultivation practices, large populations appear to have been maintained throughout the emergence of domesticates, and the resulting forms were not necessarily an improvement in terms of yield.We present a framework in which the process of domestication evolved as a landscape-level process involving large populations connected through sustained long-term human contact over large distances from which domesticate forms emerged in a complex manner as an adaptive reaction to long-term exploitation that did not necessarily provide immediate benefits.The landscape framework addresses several anomalies and radically changes the dynamic visualization of the evolution of domestication. It also opens up a list of new questions regarding the mechanisms of selection and the assembly of domestication syndrome alleles, and obliges a profound rethink of the progressive nature of domestication and human cultural evolution.