(A, C, E) Quantile-quantile plots (QQ-plots) of the SNP-specific association test statistics of the apical SNPs via (A) the proposed joint location-scale test (JLS-Fisher), (C) the regression based location-only test, and (E) Levene’s scale-only test. QQ-plots of the observed association statistics are shown in red, and the QQ-plots of the statistics calculated from the 10,000 phenotype-permutated replicates are shown in gray.