Experiment
Linkage analysis was performed on 552 10-week old male animals from a (M16i x L6)F2 intercross to identify QTLs associated with measurements of growth such as organ weight, growth rate, and adiposity. 63 polymorphic markers spanning the 19 autosomes wereused in the genome scan. Parental strain M16i is a long term selection line for rapid 3- and 6- week weight gain whereas parental strain L6 is a long term selection line for low 6-week body weight. A total of 50 significant QTLs (LOD>3.3) were mapped over15 chromosomes. More than 25% of loci mapped to mouse Chromosome 2.
On mouse Chromosome 1, QTLs for liver weight (Lvrq3), spleen weight (Splq3, Splq5), kidney weight (Kidq2), and percent water carcass weight (Pwatq1) were identified. Lvrq3 maps to 59.5cM between D1Mit180 and D1Mit72 (LOD=7.3) with L6-derived alleles conferring recessively inherited decrease in liver weight. The confidence interval of Lvrq3 spans 48.9 cM - 72.7 cM. Splq3 and Splq5 map to 67.4 cM (LOD=5.6) and 93.2 cM (LOD=5.4), respectively. Splq3 is flanked by D1Mit72 and D1Mit200; Splq5 is flanked by D1Mit200 and D1Mit223. L6-derived alleles confer decreased liver weight with recessive inheritance at Splq3 and dominant inheritance at Splq5. The confidence interval of Splq3 spans 55.2 cM - 78.1, and the confidence interval of Splq5 spans 80.9 cM - 103.5 cM. Kidq2 maps to 75.4 cM (LOD=10.2) between D1Mit72 and D1Mit200 with L6-derived alleles conferring dominantly inherited decrease in kidney weight. The confidence interval of Kidq2 spans 70 cM - 84.7 cM. Pwatq1 maps to 72.7 cM (LOD=3.7) with L6-derived alleles conferring additively inherited decrease in percent water in carcass.
Analysis Tools