how well a SNP can be genotyped), validation status (indicating how many platforms validate a SNP), minor allele frequency (MAF), and location (i.e. coding region). To ensure efficient Illumina genotyping, a potential tagSNP would not be selected if it was within 60 bp of another chosen SNP or 35 bp of any other known SNP in dbSNP. Because of the potential for some SNPs to fail in the genotyping, redundant tagSNPs were selected if the number of SNPs in a bin was large. Those SNPs that could not be tagged (i.e. singletons) were also included if their design score was greater than 0.4. Tag SNPs were first chosen in the CEPH population. If necessary to capture the diversity within the Chinese HapMap population sample, additional SNPs were selected. Genetic diversity within Chinese individuals was captured as part of a companion study within the USC Transdisciplinary Tobacco Use Research Center (75).
