QUANTITATIVE TRAIT LOCI MAPPING OF 3 LOCI CONTROLLING MORPHINE PREFERENCE USING INBRED MOUSE STRAINS

Quantitative trait loci mapping was used to identify the chromosomal l ocation of genes which contribute to oral morphine preference (in a tw o-bottle choice paradigm) of C57BL/6J mice, compared to DBA/2J mice. A n F-2 intercross of these two strains (606 mice) was phenotyped for mo rphine preference and those mice demonstrating extreme values for morp hine consumption (the highest and lowest 7.7%) were genotyped for 157 murine microsatellite polymorphisms. Maximum likelihood methods reveal ed three loci on murine chromosomes 1, 6 and 10 which are responsible for nearly 85% of the genetic variance observed between the two parent al strains.