Ten SNPs were chosen from the SNP database (http://www.ncbi.nlm.nih.gov/SNP/index.html) and the genomics database of Applied BioScience Inc, Foster City, California, with the following criteria: (1) SNPs located in coding or regulatory regions of the gene or reported to be associated with drug dependence in the literature, (2) haplotype-tagged SNPs suggested by the Haploview program41 using the default parameters, and (3) SNPs with a minor allele frequency of 0.05 or higher in the SNP database. Table 1 lists the characteristics of the selected SNPs.
