Figure 1.

(a) Scatterplot of the first two principal components (PCs) estimated from the ComBat-adjusted β-values. Each point represents an individual sample, numbered according to the subject. Two subjects, 30 and 26, are indicated in the plot to illustrate examples of subjects with low/high relative within-person variation in DNA methylation between the two time points.(b) Empirical null distribution of the average Euclidean distance between pairs of samples. Red line denotes the average within-person Euclidean distance computed across each of the n = 35 subjects.