Published quantitative trait locus (QTL) data, as well as all known rat genes and DNA markers, have since 1993 been collected and made easily accessible at the rat genome database, RatMap. The objective of the present study is to fully integrate available data concerning rat models with human genome information. The final goal of this process is to make results from any rat model experiment directly applicable to humans. The overall goal of this work is to create an automatic system which, for any given rat chromosomal region associated with a QTL, will characterize both mapped rat genes and all putative homologous human genes in that region. This article reports the use of the web application to find human gene candidates contributing to an arthritis phenotype.