A genetic linkage map of the MSM Japanese wild mouse strain with restriction landmark genomic scanning (RLGS)

A high-resolution genetic map of the Mus musculus molossinus (MSM) Japanese wild mouse strain was constructed with restriction landmark genomic scanni ng (RLGS) and compared with that of the laboratory strain C3H. MSM is phylo genetically 1 million years apart from common laboratory mouse strains and is distinctly resistant to chemical carcinogenesis. Since it exhibits frequ ent genetic polymorphisms with laboratory mice but can still be easily cros sed with laboratory strains, hybrids between MSM and carcinogen-sensitive l aboratory mouse strains provide excellent materials for analysis of modifie r genes and genetic changes during carcinogenesis. We have generated MSM ba ckcross progeny with the C3H strain, which is extremely sensitive to hepato carcinogenesis, to construct the present map. RLGS profiles with two combin ations of restriction enzymes (NotI-PvuII-PstI, NorI-PstI-PvuII) yielded mo re than 2000 spots each. The polymorphism rate was about 39.2%, and of a to tal pf 1732 polymorphic spot loci identified, 1371 could be assigned to spe cific chromosomes by comparison with 79 microsatellite marker loci. Thus, 1 450 loci, on all chromosomes except for Y, effectively mapped 90% of the ge nome (1431.7 cM length). Although some spots might be derived from the same NotI site, each NotI site potentially generating two Fragments, the presen ce of at least 515 loci groups with different progeny distribution patterns dispersed through the genome with an average spacing of 3 cM, means that t his genetic map should be useful for analysis of various biological phenome na, including carcinogenesis and ontogenesis, at the gene level.