Rice, revealed.

Researchers have finished a 6-year-long effort to sequence the genome of rice. The accomplishment makes the popular cereal the second plant ever to have its full genome sequenced. In 2003, scientists sequenced the genetics-research workhorse Arabidopsis thaliana, a mustard plant.

This latest project pooled the resources of research groups from more than 10 countries, including a team led by Robin Buell of the Institute for Genomic Research in Rockville, Md.

The groups divided the rice genome into pieces for each lab to sequence and then assembled the parts "like pieces in a jigsaw puzzle," says Buell. After analyzing the completed genome, the scientists found that rice has slightly more genes than people do--about 37,000 compared with the estimated 30,000 genes of the human genome. The researchers report their results in the Aug. 11 Nature.

Although the function of many of rice's genes remains unknown, Buell says that about 70 percent of these genes mirror those in A. thaliana. By teasing out the roles of the newly sequenced genes, researchers may find a way to improve the output of rice plants, which feed about half the world's population every day, she says.