Fuzzy: a genetic marker for warfarin resistance in the Norway rat

Summary No recombination was observed between fuzzy (jz) and warfarin resistance (RwW) in 245 rats from a backcross test for linkage. This locates fz very close to Rw in linkage group I. The map position established for fz makes this allele particularly suitable for use in combination with p (pink-eyed dilution) for linkage tests in group I and as a genetic marker for the Rw locus in studies of warfarin resistance. The map position of fz in the rat corresponds to that of fr (frizzy) in the mouse, suggesting homology between these loci in the 2 species. Fuzzy, a recessive, hypotrichotic character of the Norway rat, is controlled by an allele, designatedfz, in linkage group 1 (Palm & Ferguson, 1976; Ferguson, Irving & Stedham, 1979). Since the character is fully penetrant and appears to reduce viability only slightly, it is a potentially valuable marker for use in linkage studies. However, as it has not yet been tested against any linkage group I marker other than