The scoring method is identical to Saccone and colleagues [4] for the gene and ECR nodes. The “Addiction Systems” node adds 1 to the score for any of the 486 genes from our expert nomination process. The score for the “Mouse QTL Mapping” node is min(N/6,1), where N is the number of phenotypes identified for a gene using the systems genetic methods. This means that the score is 1 for all genes where N is greater than 6, which corresponds to the top 5% of QTL mapping results. The score is scaled down linearly when N is less than 6. Note that this particular GIN model combines information from the expert nomination process and the mouse systems genetics data in the sense that SNPs in the 486 expert nominated genes, the determination of which did not involve the mouse data, would receive an increased score if there was additional evidence from the mouse data of relevance to addiction.
