Fig. 1

CHRNA5 mRNA expression in the putamen compared across rs7164030 genotypes, as measured by qPCR. Samples homozygous for the major “A” allele (A/A) of rs7164030 have approximately 3.5-fold less CHRNA5 mRNA versus samples homozygous for the minor “G” allele, with heterozygotes exhibiting intermediate levels (ANOVA p=1.82×10⁻⁶)