Scanning of five chromosomes for alcohol consumption loci.

In our present genetic study to map Quantitative Trait Loci (QTLs) for alcohol-related behaviors, we used 44 B6.C and 36 B6.I inbred congenic Recombinant QTL Introgression (RQI) mouse strains of the b5i7 series carrying genes of BALB/cJ (C) or CXBI (I) origin on C57BL/6ByJ (B6) genetic background. Ethyl alcohol consumption (EAC) was measured in adult males, and chromosomes 1, 2, 3, 9, and 15 were scanned with polymorphic microsatellite markers. In the B6.C set of strains, multiple regression analysis yielded a model with three microsatellite markers, which explained 32% of the genetic variance (p=0.0006). The two markers with the highest significance levels in the model, D1Mit167 and D2Mit74, have been mapped to chromosome regions close to the gene opioid receptor kappa 1 (chr. 1) and opioid receptor kappa 3 (chr. 2), respectively. The results of this gene-mapping study suggest that genetic polymorphisms in kappa opioid receptors may contribute to genetic predisposition to voluntary alcohol-drinking behavior.