Minor allele (G) frequency of rs2268493 was 12%. The genotypes were not in Hardy-Weinberg equilibrium (HWE) (χ2 = 8.89, p < .05). To rule out potential problems with genotyping procedures, data from 24 randomly selected participants were genotyped again and concordance was 96%. The deviation from HWE may be because our sample is not normative; participants were selected for higher rates of aggressive behavior using the screening procedure described above. However, it remains possible that genotyping error could have led to an over-abundance of G/G’s in the sample, resulting in the deviation from HWE. In the analyses for this study, individuals with the G/A and G/G genotypes were combined into one group (i.e., carriers of the G allele) and compared to individuals with the A/A genotype. Because it is less likely that errors in genotyping would result in A/A individuals being categorized as G/G (rather, G/A individuals may have been categorized as G/G, resulting in the over-abundance of G/Gs), the deviation from HWE may be less problematic for the results of this study.
