Distribution of retroviral integrations around CpG islands and conserved noncoding sequences. (A) Distribution of the distance of MLV and HIV integration sites from the midpoint of CpG islands at 100-bp resolution. The percentage of the total number of CpG islands (n) is plotted on the y-axis. The black line indicates the distribution of control random sites. (B) Distribution of the distance of MLV and HIV integration sites from the midpoint of mammalian evolutionarily conserved noncoding sequences (CNCs) at 100-bp resolution. The percentage of the total number of CNCs (n) is plotted on the y-axis. The black line indicates the distribution of control random sites.