PWD/Ph and PWK/Ph inbred mouse strains of Mus m. musculus subspecies--a valuable resource of phenotypic variations and genomic polymorphisms.

PWD/Ph and PWK/Ph (abbreviated PW*) are highly inbred mouse strains (F66 and F70) derived from wild mice of Mus musculus musculus subspecies. When compared with laboratory inbred strains, they display a plethora of differences in many complex phenotypes such as body weight, fat distribution pattern, blood levels of intermediary metabolites, sensitivity to type-1 diabetes or behaviour patterns. The PWD/Ph genes can rescue the lethal effect of lack of the Igf2 receptor. The male-limited hybrid sterility of (PWD/Ph x laboratory strain)F1 hybrids is a specific phenotype controlled by three or four unlinked loci. These complex phenotypic traits can be genetically dissected by QTL analysis using microsatellite markers of known genetic location. The PW strains are particularly useful for such genome-wide scans since 70-80% of randomly chosen microsatellite markers are polymorphic in (PW x laboratory strain) crosses compared to 35-45% in crosses between two laboratory strains. The list of polymorphic microsatellite loci is included in this report. The high degree of sequence polymorphism allows easier distinction between paternal and maternal mRNA transcripts in PW hybrids, which makes the PW* strains a useful tool also in molecular studies of genomic imprinting. The high frequency of phenotypic differences together with the high degree of sequence polymorphism and the relatively easy breeding of PW strains make them a valuable mammalian model organism for the functional genomics of the traits of biomedical importance.