Establishment and characterization of the MSKR inbred strain originated from Japanese wild mice (Mus musculus molossinus)

A new inbred strain, MSKR, originated from Japanese wild mice was establish ed in April, 1998. The MSKR mice were 60% of the C57BL/6N inbred mice in th e 60-day body weight. Tail length/head-body length and hind-foot length/hea d-body length of the MSKR mice were significantly smaller than those of the C57BL/6N mice (0.896 vs 1.061, 0.189 vs 0.204), but ear length/head-body l ength of the MSKR mice was significantly larger than that of the C57BL/6N m ice (0.143 vs 0.137). The age of the first parturition and size of the firs t litter were 63.20 +/- 2.71 days and 6.20 +/- 0.37, respectively, at the 2 0th and 22nd inbreeding generations. Genetic characterization of the MSKR s train was performed using 34 microsatellite markers, 29 biochemical markers , 9 immunogenetic markers, 3 coat color markers, and mitochondrial DNA RFLP -haplotypes. The result indicated that this newly established inbred strain has some different gene constitution from already known molossinus and com mon laboratory strains.