For decades, the rat has been used as a model system for studying human physiology and disease. In particular, there are excellent rat models for multifactorial diseases, the genetic components of which are being hunted down with increasing vigour. Consequently, there is strong motivation to develop genetic and genomic resources for the rat, so that the wealth of phenotypic and physiological data can be exploited in genetic analyses.

The data and resources are accumulating rapidly — the rat genome is scheduled to be sequenced to at least fourfold coverage by the end of 2002 — and to provide centralized access to this information, the Rat Genome Database (RGD) was launched in June, 2000. RGD is the result of an international collaboration of rat researchers and is hosted at the Medical College of Wisconsin.

The information available at RGD includes maps (genetic and physical), genes, ESTs, simple-sequence length polymorphisms and phenotypic data for 48 important inbred rat strains. Rat genes are linked to human and mouse homologues and to related information, such as NCBI's LocusLink, the Ratmap database and the Rat Gene Index at The Institute for Genomic Research.

RGD also provides tools for data analysis, such as Metagene. Users can submit genome sequence to Metagene and the sequence is analysed by seven popular gene-prediction algorithms. Results are aligned for all packages, allowing the user to compare the output and to assess the statistical significance of the predicted coding regions. And if you're stuck for a rat person to talk to, the Rat Community Forum, also hosted by the Medical College of Wisconsin, is a good first port of call.