Co-expression network modules associated with chronological age. Six mutually exclusive gene network modules with coordinate gene expression profiles associated with chronological age were identified in 1,264 monocyte samples (using WGCNA), ranging in size from 3 to 1,466 genes. For each module (x-axis), the partial correlation between age and the module eigengene is shown (y-axis); covariates included race, sex, site of data collection, and residual sample contamination with non-targeted cells. Below each module is the number of genes assigned to the module, and the direction of expression association with age; network modules discussed in further detail include the ‘black’ module (containing three genes: MCL1, TSC22D3, and CEBPD), and the ‘blue’ and ‘turquoise’ modules (which were significantly enriched with age-related pathways shown in Table 1). The significance of the module eigengene association with age is denoted as: * p < 0.008 (Bonferroni adjusted significance threshold for testing six modules, alpha = 0.05), and ** p ≤ 1x10−6.