The genetic data indicate that important domestication traits are under simple genetic control but also, as Gross and Olsen write, that there are "many ways to make a domesticated plant." For example, genetic analysis shows that barley, common beans and Asian rice were domesticated more than once, a remarkable finding because the archeological evidence on this question is inconclusive.
QTL maps have also revealed that the same traits are sometimes controlled by different constellations of genes. For example, different genes prevent shattering in the two domesticated lineages of barley.
Although QTL mapping has led to many insights about the domestication of plants, Gross and Olsen emphasize that genes cannot tell us everything. Trying to read the history of domestication out of the genomes of existing crop plants is like trying to read a book with many missing pages.
There's a simple reason for this. Living crops cannot provide information about any plant lineage that did not ultimately contribute to a modern crop. So the genetic record is silent about domestication experiments that ultimately failed or were abandoned. If these experiments left a record, they left it only in archaeobotanical remains which is what makes it difficult to reconcile that record with the genetic data.
Sticky rice, fragrant rice and other fun stuff
The second step in plant domestication is the fun one. Once a plant has become amenable to sowing and reaping, farmers set to work to improve it or diversify it.
One such improvement is sticky rice, a type of short-grained, famously glutinous Asian rice. Olsen, who has studied the origins of sticky rice, says that usually "about 20 percent of the starch in the rice is amylose and the rest is another starch called amylopectin. Amylose is an unbranched molecule
|Contact: Diana Lutz|
Washington University in St. Louis