Trans-ethnic comparison of association signals at a haplotype level has shown that the H1 haplotype exerts the most significant effect on BMI and type 2 diabetes (Table 2), indicating that the cluster-A SNPs tagging H1 are most correlated with the causal variant(s) at FTO. The phylogeny of haplotypes can clearly account for the repeatedly argued discrepancy of rs9939609–trait association between Africans and non-Africans [6], [7]. The gene discussed is FTO; the disease is type 2 diabetes mellitus.