Some human transcription factors can bind to both methylated and non-methylated DNA sequences. Hu et al. examined the ability of 17 human transcription factors to bind to 150 different DNA motifs containing methylated or non-methylated CpG islands. Each row represents one transcription factor. For each motif, some transcription factors bound only to the methylated version (red), some to only the non-methylated version (blue); some to both methylated and non-methylated versions (green), and some to neither (grey). From Figure 2a in Hu et al., 2013.