Fig. 2

Baseline skeletal muscle DNA methylation differences. A Unsupervised principal component analysis using methylation percentage of all CpG sites with 10X coverage across the target probes. Samples are coloured by group (green = control group/CG, orange = endurance group/EG, blue = strength group/SG). The dashed ellipses represent the 95% confidence regions for the multivariate mean of each group in the PC1 vs PC2 space, providing a visual representation of the dispersion and overlap of the groups. See Additional file 6 for individual methylation percentages. B Number of differentially methylated regions (DMRs) and C number of differentially methylated positions (DMPs) comparing the 3 groups at rest. Red indicates higher methylation and blue indicates lower methylation. See Additional file 4 for all DMRs and DMPs. D–G Top: bar plots of selected DMRs at baseline comparing EG, SG, and CG. Overlapping DMRs from different group comparisons are plotted in the same figure. Results are shown as mean ± SEM for n = 8 subjects for FOXO1 (D), MYF5 (E), CREB5 (F), and MYL3 (G). ∗ indicates p < 0.05. Bottom: Scatter plots showing correlation between mean methylation of DMRs and gene expression of the associated gene for all samples. R = Spearman correlation coefficient. Full line = linear regression model including subjects from all groups. Dotted line = linear regression model only including trained individuals (SG and EG). Y-axes vary for better visualisation of the regression lines. See Additional file 6 for individual methylation percentages and TPM values