Neither controls for occult stratification nor for poor technical quality explain the nominally-positive SNPs from the successful vs unsuccessful quitter comparisons. The SNPs that display the largest allele frequency differences between European- and African-American controls and the SNPs that display the largest between-pool variances do not overlap with those that distinguish successful vs unsuccessful quitters at levels significantly larger than those anticipated by chance (131 vs 114 and 143 vs 114, respectively).
