MAPPING OF PCR-BASED MARKERS FOR MOUSE CHROMOSOME-4 ON A BACKCROSS PENETRANT FOR THE MISTY (M) MUTATION

A genetic linkage map for mouse Chromosome (Chr) 4 (MMU 4) has been co nstructed with an intersubspecific backcross between the C57BL/KsJ str ain homozygous for the misty (m) coat color locus and the inbred Mus m usculus musculus Czech II strain. Several recently developed PCR-based simple sequence length polymorphism (SSLP) markers have been intercal ated among gene-based markers including six anchor loci on mouse Chr 4 to assemble this map. Marker order and genetic distances are similar to the composite genetic linkage map compiled from crosses between a v ariety of other inbred and feral mouse strains. Transmission ratio dis tortion in favor of feral alleles is apparent for a region of distal M MU 4. In addition, the misty phenotype is more fully penetrant in the present backcross than in other reported interspecific and intersubspe cific crosses. Backcrosses employing inbred Mus musculus musculus stra ins may allow reliable phenotyping and mapping of mouse mutations disp laying complex phenotypes with incomplete and/or ambigious penetrance on other feral genetic backgrounds.