"The Modern View of Domestication," a special feature of The Proceedings of the National Academy of Sciences (PNAS) published April 29, raises a number of startling questions about a transition in our deep history that most of us take for granted. At the end of the last Ice Age, people in many spots around the globe shifted from hunting animals and gathering fruits and tubers to cultivating livestock and plants.
It seems so straightforward and yet the more scientists learn, the more complex the story becomes. Recently, geneticists and archeologists working on domestication compared notes and up popped a question of timing. Did domesticating a plant typically take a few hundred or many thousands of years?
Genetic studies often indicate that domestication traits have a fairly simple genetic basis, which should facilitate their rapid evolution under selection. On the other hand, recent archeological studies of crop domestication have suggested a relatively slow spread and fixation of domestication traits.
In this special issue of PNAS, Washington University in St. Louis biologist Ken Olsen, PhD, and colleagues ask whether complex genetic interactions might have slowed the rate at which early farmers were able to shape plant characteristics, thus reconciling the genetic and archeological findings.
Olsen, associate professor in the Department of Biology in Arts & Sciences, together with colleagues from Oklahoma State University and the University of Guelph in Ontario, Canada, conclude that these interactions are not a key factor in domesticated plants. The process of domestication, Olsen said, favored gene variants (alleles) that are relatively insensitive to background effects and highly responsive to selection.
But finding these alleles in the first place must have difficult, Olsen said. Only a subset of the genes in the wild population would have reliably produced a favored trait regardless
|Contact: Diana Lutz|
Washington University in St. Louis