Fig. 1.

(A) Starting with the Kyoto Encyclopedia of Genes and Genomes dopamine pathway, we selected a set of genes directly related to dopamine functioning (Table 1). For each gene, we took all available SNPs in the GWA dataset and conducted PCA to account for correlation due to LD. On the phenotype side, we used a laboratory-based economic game (patent race). These were then combined in our computational model, where parameters were estimated using maximum likelihood. Hypothesis testing was done using two different methods: (i) permutation P values under the null hypothesis of no association and (ii) empirical P values by comparing to randomly matched genes in the GWA dataset. (B) Dopamine pathway genes are represented in a stylized version of the dopamine synapse and include dopamine genes directly involved in synthesis (green), uptake (blue), and metabolism (pink) and receptors (violet). Certain details, such as presynaptic autoreceptors, have been omitted for clarity. (C) In the patent race, subjects were presented with (i) the game with information regarding their endowment, the endowment of the opponent, and the potential prize. (ii) Subjects inputted the decision (self-paced) by pressing a button mapped to the desired investment amount from the initial endowment. (iii) After a brief delay, the opponent’s choice was revealed. If the subject’s investment was strictly more than those of the opponent, the subject won the prize; otherwise, the subject lost the prize. In either case, the subject kept the portion of the endowment not invested.