of extreme iHS values in the ASN population. Overall, 40% of the SNPs in this bin showed extreme values in AFR and 15% of the SNPs in this bin showed extreme values in EUR. As these SNPs are absent from the ASN population, none showed extreme iHS values. The dense clustering of extreme iHS values in AFR and EUR is rarely expected under a neutral model, and is consistent with the hypothesis of the action of recent selection. In EUR, all of the SNPs in this LD bin with extreme iHS values had positive values and all were shared with AFR. Thus, in both populations, the ancestral allele associated with increased risk for nicotine dependence and decreased risk for cocaine addiction is being favored.
