FIGURE 2. Genetic loci perturb molecular phenotypes that in turn lead to variations in disease-associated traits.
From the following article:
Variations in DNA elucidate molecular networks that cause disease
Yanqing Chen, Jun Zhu, Pek Yee Lum, Xia Yang, Shirly Pinto, Douglas J. MacNeil, Chunsheng Zhang, John Lamb, Stephen Edwards, Solveig K. Sieberts, Amy Leonardson, Lawrence W. Castellini, Susanna Wang, Marie-France Champy, Bin Zhang, Valur Emilsson, Sudheer Doss, Anatole Ghazalpour, Steve Horvath, Thomas A. Drake, Aldons J. Lusis & Eric E. Schadt
Nature 452, 429-435(27 March 2008)
doi:10.1038/nature06757
a, Lod score plots for weight (solid black line), Apoa2 liver expression (solid red), Rgs5 liver expression (solid blue) and BB433460 liver expression (solid green) traits in the B 
H cross. The dashed curves represent the lod score curves for weight conditional on the Apoa2 (dashed red), Rgs5 (dashed blue) and BB433460 (dashed green) liver gene expression traits. Conditioning on Apoa2 expression does not significantly reduce the weight lod score (independent relationship), whereas conditioning on Rgs5 or BB433460 does (causal relationship). b, Relationships supported between the expression and weight traits described in a: Apoa2 (top), Rgs5 (middle) and BB433460 (bottom) are predicted to be related to weight in an independent (Apoa2) and causal (Rgs5 and BB433460) way. Percentages represent the number of times the model shown was inferred out of 1,000 random samples drawn from the B H cross. c, Generalization of the relationship discovered between BB433460 and weight, in which genetic loci (Li) and environment perturb molecular networks of genes (Gi) that in turn leads to disease.
