Expanding the Ranks of Vertebrate Genomes

When the brown Norway rat1 and the red jungle fowl2 joined the ranks of the sequenced in 2004, two unsung heroes of experimental biology finally got their due. Although the projects met with some resistance at the start, a genetics toolbox has been assembled that is worthy of these animals' research status, and scientists are starting to succeed in applying its contents.

Used in countless drug and toxicity studies, the rat has long been a pharmacological workhorse, says Richard Gibbs at the Baylor College of Medicine in Houston. But unlike in mice, rat genes could not be knocked out to reveal their associated traits, so the rat lagged behind as a genetic model. "Quite simply, [the genome sequence] revolutionized the work you could do in rats," says Howard Jacob at the Medical College of Wisconsin and director of the Rat Genome Database.

The chicken and its easily scrutinized eggs have ...