Anyone who has seen teosinte, the wild grass from which maize (corn) evolved, might be forgiven for assuming many genetic changes underlie the transformation of one plant to the other.
However, a method for exploring the genetics of domestication called Quantitative Trait Locus (QTL) mapping has revealed that only modest modifications are needed to convert a wild plant to a crop plant. Some major transitions in phenotype can even be achieved by a single genetic change.
The few artificial experiments in domestication that have been conducted have also shown that it is possible to achieve domesticate-like plants in fewer than 20 generations.
None of this pleases archaeobotanists, who try to piece together the history of plant domestication from scraps of ancient plant remains.
Their data are sparse and unimpressive a 10,000-year-old squash seed found in a cave in Oaxaca, Mexico, or four 12,000-year-old grains of rice recovered from a rock shelter in Hunan Province in China but they have their own irrefutable reality.
"There's been an argument in the recent archeological literature that genetics gives a false picture of domestication as a rapid, geographically localized process," comments Kenneth M. Olsen, PhD, assistant professor of biology in Arts & Sciences at Washington University. "They argue instead that domestication likely involved much triral and error in many different geographic regions over a long period of time."
In a review of the genetics of plant domestication published in the advance online edition of Trends in Plant Science, Olsen, who uses genetic approaches to study the domestication of rice, cassava and coconut, and Briana L. Gross, PhD, a postdoctoral research scholar in his lab, review the recent genetic data and argue that genetic evidence doesn't conflict with the archeological evidence that domestication was gradual, dispersed and tentative.
The Domestication Syn
|Contact: Diana Lutz|
Washington University in St. Louis