DNA fingerprinting of trait-selected mouse lines and linkage analysis in reference families.

The first aim of the study was the molecular genetic characterization of long-term trait-selected (growth, adaptability and fertility) lines of mice using multilocus DNA fingerprinting with the simple tandem repetitive oligonucleotide probes (GAA)6 and (GACA)4. Secondly polymorphic markers were screened for association with growth performance based on DNA fingerprint analysis in reference families. Pooled DNA samples of ten unrelated mice of trait-selected mouse lines (over 40 generations) and the unselected control lines were analyzed. Resulting differences in band patterns were reanalyzed comparing individual fingerprints of the animals included in the pooled DNA samples of the different lines. Between the mouse lines about 30% of analyzed fingerprint bands were polymorphic. Individuals of long-term selected mouse lines show only a few individual-specific bands. Most polymorphic bands observed in DNA mixes appear in all animals included in the DNA mix of the corresponding line. Line-specific DNA fingerprint bands were analyzed for their inheritance and linkage with growth performance in reference families using animals with extreme growth performance of the first backcross after crossing of growth-selected with unselected mice. Scanning the distribution of line-specific bands in the reference panel few bands were identified which are associated with growth performance. They appear as useful markers for growth selection. Nevertheless most line-specific bands result from genetic drift rather than from selection.