A whole-genome radiation hybrid panel and framework map of the rat genome

The rat is a widely used model organism in medical and pharmaceutical research, and its physiology is better understood than that of any other vertebrate with the exception of human. The rat is a particularly useful model for investigating polygenic diseases, yet rat genetics has remained under-researched compared with that of the mouse (Jacob 1999; James and Lindpaintner 1997). This is being redressed with the publication of genome-spanning genetic maps, the production of many thousands of genetic markers (Steen et al. 1999; Watanabe et al. 1999), and construction of large-insert clone libraries (loc.cit.). With the availability of these new genetic and genomic resources, an efficient means of deploying them in the various disease model studies is required. Radiation hybrid (RH) mapping is a powerful tool to achieve this goal because it is rapid, has 100% genome coverage, higher resolution than meiotic maps, allows for integration of genetic and gene-based markers, and provides a single resource that can be distributed to any laboratory (McCarthy 1996). Furthermore, non-polymorphic markers may be RH mapped, a particular advantage for the rat because genetic maps have limitations because only approximately 50% of genetic markers are polymorphic in a cross between any two inbred strains.