to identify those genes which most broadly and reliably related to the behavioral functions assessed. A ranked ordering of genes was generated based on each gene's connectivity to phenotypes. It should be noted that this ranking is somewhat biased by those traits which were measured in multiple assays or multiple time points. These rankings were made a part of the NeuroSNP database for supplementing addiction arrays (Saccone et al. 2009). The most highly connected gene was Mef2c; interestingly this gene also resides in the Chromosome 13 QTL interval for several behavioral factors. It should be noted that the composition of the behavioral phenotypes in this analysis will shape the results obtained. For example, some aspects of behavior such as locomotor behavior and anxiety-like behaviors have many measures in this study. As such, they are over-weighted relative to other aspects of behavior. Despite the overweighting of certain measures, the most highly connected genes are associated with approximately 150 unique traits. These traits include traits measuring anxiety, stress and pain sensitivity and span multiple test batteries namely cocaine, general behavior, morphine, ethanol and pain.
