Our approach aims to provide deeper coverage and enable analysis of both common and rare variants, without unnecessarily increasing genotyping costs and effort. It involves selecting a minimal set of tagSNPs that represent two or more independent sets of SNPs from each candidate gene. A final tagSNP list generated with our combined selection method is limited to the ethnicity it was generated for. TagSNP selection for other ethnicities would require separate analyses, ideally using HapMap data from that population and re-sequencing data from the same population. Transferability in between study populations of the same ethnicity (e.g. oldest-old, centenarians, or super-centenarians) is feasible but would solely depend on the presence of the private re-sequencing variants amongst these populations.
