The Rat Genome Database (RGD) is the premiere location for rat genomics, genetics, physiology and functional data, as well as data for comparative genomics between rat, human and mouse. RGD is responsible for attaching biological information to the rat genome via structured vocabulary, or ontology, annotations assigned to genes and quantitative trait loci (QTL), and for consolidating rat strain data and making it available to the research community. RGD is working with groups such as the Programs for Genomic Applications at MCW and the National BioResource Project for the Rat (NBPR-Rat) in Japan to collect and make available comprehensive physiologic data for a variety of rat strains. They are also developing a suite of tools for mining and analyzing genomic, physiologic and functional dat