Although cigarette smoking and other tobacco use is common in other world populations, the majority of the large-scale genetic studies to date have been performed in populations of European descent. The chromosome 15 region that is associated with smoking behaviors in populations of European descent shows great genetic diversity in populations of Asian and African origin. This varying allele frequency results in different patterns of correlated SNPs, or linkage disequilibrium, in populations of different origin. While the frequency of disease causing genetic markers may vary across populations, their biological impact on the risk for common diseases is typically consistent across different populations [26]. This expected biological consistency, along with different patterns of genetic correlation between SNPs, can be leveraged to refine association signals by narrowing down the most likely biologically causative variants.
