Validity of tagging SNPs across populations for association studies

Recent advances in high throughput genotyping technologies will allow large-scale association studies to disentangle the genetic basis of human common diseases. Currently, a large-scale genotyping effort is being carried out by the HapMap project and the outcome of this project is expected to help researchers in their efforts to understand how genetic variation influences susceptibility to disease. However, there is some controversy on whether this huge public effort will be of value for those populations not studied in the HapMap project. Here, we present simulation results based on the empirical distribution of linkage disequilibrium (LD) on a large chromosomal region (10 Mb) on human chromosome 20(1,2) for two European and two Asian populations. These results show that statistical power to detect associations does not depend on the population were SNP tagging was performed.