Differences in the correlational structure of markers spanning the region 15q25 between populations result in distinct sub-bins of correlated markers among Asian and African American populations which provide an opportunity to refine the source of the previously reported signals. For example, bin A, consisting of 52 variants including rs16969968, separates into 20 sub-bins in Asians (based on 1000 Genomes Pilot 1 JPT/CHB) and 38 sub-bins in African Americans (based on combined information from the 1000 Genomes Pilot 1 YRI and HapMap 3 Release 2 ASW) [Altshuler, et al. 2010]. In particular, rs16969968 and rs1051730 are highly correlated in European ancestry (r2=1) and Asian populations (r2=1), but display only moderate correlation (r2=0.40) in the African American population. These differences in genetic architecture can be used to dissect the association signals.
