Fig. 1

Global difference in the DNA methylation level between the LCLs and PBCs. a Principal component analysis (PCA) plot. PCA was performed using the methylation level of the 400,240 sites on autosomes. The LCL and PBC samples are shown in black and blue dots, respectively. b Volcano plot with the difference of the average of DNA methylation level on the x-axis and the P value (−log₁₀ P) obtained via glm analysis on the y-axis. Each color shows the dot density (100 < n, 80 < n ≤ 100, 60 < n ≤ 80, 40 < n ≤ 60, 20 < n ≤ 40, 10 < n ≤ 20 and n ≤ 10 per unit area (0.002 × 1 for x and y-axis, respectively) in red, yellow, green, sky blue, blue, pink, and black, respectively)