Table 1 Results of CIT for fat pad weights and organ weights of male mice obtained from an F2 intercross population between KO and B6J strains.

From: Genetic identification of Ly75 as a novel quantitative trait gene for resistance to obesity in mice

Trait Genotype P value Relationship modela
KO/B6J B6J/B6J Test 1 Test 2 Test 3 Test 4
No. of mice 12 12      
Liver Ly75 expression level 1.00 ± 0.09 2.13 ± 0.09   1.6E-08    
Total fat pad weight (g) 5.258 ± 0.185 4.580 ± 0.185 0.017 5.7E-07 0.081b 0.76 Causalb
Inguinal fat pad weight (g) 2.416 ± 0.093 2.065 ± 0.093 0.014 6.6E-07 0.061b 0.71 Causalb
Gonadal fat pad weight (g) 1.860 ± 0.068 1.675 ± 0.068 0.068 1.3E-07 0.055 0.43  
Perirenal fat pad weight (g) 0.981 ± 0.033 0.840 ± 0.033 0.0063 9.7E-07 0.54 0.39  
Liver weight (g) 1.158 ± 0.025 1.149 ± 0.025 0.82 2.7E-08 0.32 0.44  
Kidney weight (g) 0.357 ± 0.007 0.377 ± 0.007 0.051 1.9E-07 0.73 0.51  
Heart weight (g) 0.117 ± 0.002 0.121 ± 0.002 0.28 5.8E-08 0.90 0.69  
Lung weight (g) 0.138 ± 0.002 0.144 ± 0.002 0.024 2.6E-07 0.88 0.33  
Spleen weight (g) 0.076 ± 0.034 0.086 ± 0.034 0.050 2.3E-07 0.43 0.78  
Testis weight (g) 0.218 ± 0.015 0.196 ± 0.015 0.31 2.0E-08 0.26 0.15  
Adjusted total fat pad weight −6.112 ± 0.077 −6.433 ± 0.077 0.0074 1.0E-06 0.022 0.55 Causal
Adjusted inguinal fat pad weight −3.326 ± 0.038 −3.497 ± 0.038 0.0045 1.4E-06 0.008 0.43 Causal
Adjusted gonadal fat pad weight −1.672 ± 0.042 −1.747 ± 0.042 0.22 3.6E-08 0.047 0.24  
Adjusted perirenal fat pad weight −1.114 ± 0.013 −1.189 ± 0.013 5.7E-04 1.1E-06 0.61 0.029  
Adjusted liver weight 0.067 ± 0.016 0.093 ± 0.016 0.27 3.5E-08 0.52 0.28  
Adjusted kidney weight 0.146 ± 0.005 0.173 ± 0.005 0.0018 3.1E-06 0.34 0.42  
Adjusted heart weight 0.055 ± 0.002 0.060 ± 0.002 0.047 2.2E-07 0.55 0.65  
Adjusted lung weight 0.119 ± 0.002 0.126 ± 0.002 0.011 5.1E-07 0.76 0.31  
Adjusted spleen weight 0.016 ± 0.003 0.028 ± 0.003 0.013 7.1E-07 0.26 0.78  
Adjusted testis weight −0.034 ± 0.015 −0.049 ± 0.015 0.50 1.3E-08 0.17 0.13  
  1. Data for two genotypes are presented as the least squares mean ± S.E.M. adjusted for a litter effect. Adjusted data were obtained by adjustment of the raw data by a litter effect and body weight at 16 weeks of age. Total fat pad weight is the sum of weights of inguinal, gonadal and perirenal fat pads. The P value for the liver Ly75 expression level shown in the table was obtained by a simple association analysis without conditioning on any trait values. See Fig. 3b for detailed methods of Tests 1 to 4. aThe causal relationship model indicates that the genotypic difference causes the trait difference via the Ly75 expression difference. bThe P value is marginal.