Once data were cleaned for quality control, genotypic data was available on 580 individuals of Finnish descent. An analysis of the population structure of the sample conducted in Eigenstrat (Price et al., 2006), a software program that uses principal components analysis to detect population stratification in genome-wide association studies, indicated a single ethnicity factor; thus all individuals were included in association analyses. Information on the genotyped SNPs, including chromosomal location and minor allele frequency is provided in Table 1. These thirty-one SNPs represent five different haplotype blocks across DRD2/ANKK1 (Figure 2). These SNPs are correlated (r2 range from .21–.93) yet represent five semi-independent signals (defined by r2<0.5) across DRD2/ANKK1 as indicated by a Nyholt correction for related SNPs (Nyholt et al., 2004).
