Figure 1

Representative Scatter plot from sequenom data. The left panel (a) and right panel (b) illustrate the scatter plot of rs1799732and rs1125394 SNPs within DRD2 gene, respectively. These two SNPs showed the strongest statistical evidence for association with substance addiction in Arab population. The X and Y axes on both plots denote the mass height measurement for the two alleles (C, C.DEL, low mass allele versus high mass allele) at the rs1799732 SNP (panel a) and for the two alleles (G, A, low mass allele versus high mass allele) at the rs1125394 SNP (panel b). Each point represents the measurements for a single individual. The points in the both panels are colored according to the genotype calls. For example in the left panel (a), green color denotes –C genotype; yellow color denotes C/-C genotype and blue color denotes CC genotype and red color denotes no call. Genotypes determined by sequenom MassARRAY^® system (iPLEX GOLD) for all 49 SNPs were highly accurate with average success rate 100%. Genotype discrepancy average (±SD) rate across the 49 loci were only 0.02% (±0.06%) in the whole cohort (460 subjects)