Quantitative trait loci associated with short-term intake of sucrose, saccharin and quinine solutions in laboratory mice

The goal of this study was simultaneously to map two genetic loci which, co llectively, have a large effect on intake of sucrose, saccharin and quinine solutions in mice. These loci had been previously identified using long-te rm measurements with the traditional two-bottle test, but the present study used a short-term, one-bottle test, intake of distilled water, 100 mM sucr ose, 10 mM sodium saccharin and 1.1 mM quinine HCl over 6 h was measured on two occasions from a non-deprived group of 61 male and 72 female F-2 mice derived from a cross of the C57BL/6J and DBA/2J mouse strains and used to d etect quantitative trait loci (QTL). DNA from each animal was typed for pol ymorphisms in anonymous microsatellite markers on mouse chromosomes 4 and 6 . Saccharin and sucrose relevant QTL were detected on distal chromosome 4 a nd a quinine relevant QTL was detected on medial/distal chromosome 6 in the region of Prp. The location of these QTL and the proportion of phenotypic variance they accounted for were similar to those arrived at following prev ious determinations using the two-bottle test. Measurement stability for th e three gustatory phenotypes was high, product-moment correlation coefficie nts between first and second determinations varying between similar to 0.80 for sucrose and saccharin and 0.73 for quinine. QTL parameters assessed in dependently for first and second presentations of sucrose and saccharin wer e stable, but the location of the quinine QTL differed between presentation s. The present experiment illustrates the utility of a 6 h fluid intake tes t in the mapping of Sac and Qui loci. The short duration of the test provid es a simple means of measuring variation in gustatory processes and the dis covery that these loci influence short-term as well as long-term fluid inta ke extends understanding of the mechanism of gene action.