Figure 3. Genetic control of PFC gene expression.

a, Position and strength of associations of SNP genotype with gene expression levels (distance of the SNP from the associated TSS is plotted on the x axis). Only gene–SNP pairs lying on the same chromosome are displayed here. Negative log₁₀(P value) is on the y axis. Only P values <0.0001 are included in this analysis. The genome-wide Bonferroni-corrected P = 0.05 is shown as a horizontal dashed grey line: P = 0.05/1.89 × 10¹⁰ associations = 2.6 × 10⁻¹² (11.6 on this y-axis scale). The numbers of associations listed in the plot refer to those passing this genome-wide alpha level. Both solid blue curves depict a local nonlinear regression fit (loess, span = 0.5) of association strength across distance from the TSS. The blue fit lying close to the y axis is a fit plotted in the same scale as the plotted P values (y axis at left). The second blue fit is the same fit, plotted on an expanded y axis (y axis at right). The minimum value of this fit both upstream and downstream from the TSS (that is, approximately where the local estimate of enrichment for greater association reaches zero) is marked with a vertical blue dashed line. b, The most significant observed association of a single SNP with the expression of one gene across the lifespan (highlighted in a in green): the rs1045599 SNP lies within the ZSWIM7 gene on chromosome 17 (ZSWIM7, zinc finger, SWIM-type containing 7). Age scales are defined as in Fig. 2b. ZSWIM7 expression level (normalized log₂(sample/reference)) is on the y axis and is coloured by rs1045599 genotype.