Figure 1

Preterm-associated differentially methylated probes (DMPs) at birth overlap with age-associated DMPs. (A) Multi-dimensional scaling (MDS) and (B) heatmap plots of 1,555 significant preterm birth DMPs (comparing preterm birth samples with term birth samples). (C) MDS and (D) heatmap plots of 3,244 combined age DMPs with β > 0.2 (comparing all birth samples with all samples obtained at 18 years). (E,F) Heat diagrams displaying all birth DMPs (upper rows) with probes colored by the direction of methylation change from preterm to term, either increasing (yellow shading) or decreasing (blue shading). Comparison of overlap of birth DMPs and age DMPs determined using either (E) preterm or (F) term subjects showed a high proportion of sites that differed in a similar direction when assessing methylation changes with age in preterm subjects (934 probes changed in the same direction; 34 probes changed in the opposite direction). By contrast, methylation changes with age in term subjects showed more sites that differed in the opposite direction with age (300 probes changed in the same direction; 431 probes changed in the opposite direction). The sample groups are color coded as follows: term birth, blue; preterm birth, black; term birth at 18 years, green; preterm at 18 years, red.