Lith6: A New QTL for Cholesterol Gallstones from an Intercross of CAST/Ei and DBA/2J Inbred Mouse Strains Short Title: Lith6 Contributes to Cholesterol Gallstones

A complex genetic basis determines the individual predisposition to develop cholesterol gallstones in response to environmental factors. We employed quantitative trait locus (QTL) analyses of an intercross between inbred strains CAST/Ei (susceptible) and DBA/2J (resistant) to determine the subset of gallstone susceptibility (Lith) genes these strains possess. Parental and F1 mice of both genders and male intercross offspring were evaluated for gallstone formation after feeding a lithogenic. Linkage analysis was performed using a form of multiple interval mapping. One significant QTL co-localized with Lith1 (Chromosome 2, 50 cM), a locus identified previously. Significant, new QTL were detected and named Lith10 (Chromosome 6, 4 cM), Lith6 (Chromosome 6, 54 cM) and Lith11 (Chromosome 8, 58 cM). Statistical and genetic analyses suggest that Lith6 comprises two QTL in close proximity. Our molecular and genetic data support the candidacy of Pparg and Slc21a1, encoding peroxisome proliferator activated receptor γ (Pparg) and the basolateral bile acid transporter SLC21A1 (Slc21a1/ Oatp1), respectively, as genes underlying Lith6.