The complex origins of domesticated crops in the Fertile Crescent

Abstract

A combination of genetics and archaeology is revealing the complexity of the relationships between crop plants and their wild ancestors. Archaeobotanical studies are showing that acquisition of the full set of traits observed in domesticated cereals was a protracted process, intermediate stages being seen at early farming sites throughout the Fertile Crescent. New genetic data are confirming the multiregional nature of cereal domestication, correcting a previous view that each crop was domesticated by a rapid, unique and geographically localised process. Here we review the evidence that has prompted this reevaluation of the origins of domesticated crops in the Fertile Crescent and highlight the impact that this new multiregional model is having on modern breeding programmes.The importance of agriculture The beginning of agriculture around 10 000 years ago has repeatedly been seen as the major transition in the human past, a changeover from the natural environment in control of humans, to humans in control of the natural environment. Before agriculture, humans were hunter-gatherers, dependent on wild resources for their nutritional requirements, which led to a largely nomadic lifestyle dictated by the annual cycle of animal and plant availability. The cultivation of plants and the husbandry of animals enabled humans to exert a measure of control over their food resources, protecting them from climatic and environmental uncertainty. As a result of further stabilisation and increase in the food supply, populations grew rapidly and the need for all members of a community to devote themselves to food procurement declined, leading to stratified societies and the elaborate civilisations and world systems of the historic period. Our present-day dependence on agriculture needs no emphasis: without it the world would support only a fraction of the current human population.As such a key episode, it is no surprise that a diversity of research approaches has been applied to the study of agricultural origins. For archaeologists, agriculture is a central component in the cultural changes associated with the beginning of the Neolithic (see Glossary), with much of the recent focus on placing the domestication of plants in its correct context within the package of changes originally described by Gordon Childe as a 'revolution' [1] but now viewed as a series of distinct episodes occurring at different places at different times. Implicit in this debate has been a recognition that the transition to agriculture is itself a multi-episode process that begins with gathering from the wild and ends with the cultivation of plants that have undergone the full suite of genetic and phenotypic changes that characterise the domesticated crop [2,3]. Anthropologists, ecologists and evolutionists have proposed various models for the role of humans in this multi-episode process, these ranging from a view of agriculture as one of the inspired human inventions of the past [4] to hypotheses that define domestication as the outcome of a natural coevolu...

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Evolution of the VvMybA gene family, the major determinant of berry colour in cultivated grapevine (Vitis vinifera L.)

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