In comparing results related to successful abstinence, we use less stringent criteria. We focus on autosomal SNPs that display three features [see additional file 1]: 1) they display t values with p < 0.01 nominal significance in the current dataset of successful vs unsuccessful quitters; 2) they lie within clusters of at least three such nominally positive SNPs so that each positive SNP lies within 0.1 Mb of the nearest positive SNP; 3) they lie within genes whose functions can be inferred. We also compared these observed results to those expected by chance, based on independence of SNP allelic frequency estimates under the null hypothesis, using 10,000 – 100,000 Monte Carlo simulation trials on the database from the current study's results, as noted above [21].
