Q-Q plot of observed P values against theoretical P values for factor analysis (red dots) and single gene–based methods (in blue). Q-Q plot of observed P values against theoretical P values for factor analysis (red dots) and single gene–based methods (in blue). Permutations (in green) show the results of a combined analysis of 10 permuted datasets. Horizontal lines show Bonferroni significance thresholds accounting for different numbers of tests (186 tests for single gene measures in blue, 930 for factor analysis in red, and 9300 for the combined 10 permutation analyses in green). Andrew Anand Brown et al. G3 2015;5:839-847 ©2015 by Genetics Society of America