Fig. 2: Evolutionary changes in CG methylation.

a Heatmap representation of mean DNA methylation of all 23,703 human DMRs in the three species illustrates dramatic reduction of CG methylation in human prefrontal cortex, especially in neurons. b Numbers of DMRs in NeuN+ and OLIG2+ cells in human and chimpanzee frontal cortex. c An example of the relationship between human neuron-hypo CG DMR and other epigenetic marks in the CLUL1 locus, a gene widely expressed in the brain. This DMR overlaps with multiple other epigenetic marks of active chromatin in the human brain, including neuron-specific ATAC-Seq peak, neuron-specific H3K4me3 peak, neuron-specific H3K27ac peak. This DMR also overlaps with a human-specific brain H3K4me3 peak compared to chimpanzee and macaque. Box represents a range from the first quartile to the third quartile. The line in the box indicates the median value. The minima and maxima are within 1.5 times the distance between the first and third quartiles from box. Source data are provided as a Source Data file. Cell-type images were color modified from the original image, which was created by Akiyao and available at the Wikimedia Commons under the Creative Commons license (https://creativecommons.org/licenses/by-sa/3.0/deed.en).