Fig. 1From: Combined genetic influence of the nicotinic receptor gene cluster CHRNA5/A3/B4 on nicotine dependenceHeatmap of linkage disequilibrium (LD) values (R2) between candidate SNPs in the CHRNA5/A3/B4 locus. Pairwise LD values (Caucasians) were calculated between candidate variants selected by GWAS hits/eQTLs overlap, top eQTLs, and regulatory regions in the CHRNA5/A3/B4 nicotinic receptor locus. On the basis of pairwise LD (R2), the candidate SNPs were grouped into four distinct LD blocks; cluster 1 to 4. The heatmap is independent of genomic location of each SNPBack to article page