Detection of 5-hmC is highly reproducible and correlated among primates. A) Scatter plots of human brain methylation data (5-hmC) generated from biological replicates run on the HumanMethylation450 BeadChips are shown to have a mean R2 > 0.95. Data for each probe is represented as a blue dot. For all scatter plots, the diagonal red line indicates the regression line and the x and y-axes indicate the methylation level for each replicate (A) or the median methylation values of the samples for each species (C). B) The density (y-axis) of probes at each methylation level (x-axis; beta) in human brain samples (N = 3) that were either interrogated for total methylation (5mc + 5hmc; black line) or 5-hmC levels (5hmc; blue line). C) Scatter plot showing the 5-hmC correlations between rhesus (y-axis) and human (x-axis) data. Each probe is represented as a colored dot that are mostly light blue but become dark blue, green, yellow, or red as the density of loci increases. D) The density (y-axis) of probes at each methylation level (x-axis; beta) in human (red; N = 3), rhesus (blue; N = 7), and mouse (green; N = 3) brain samples that were either interrogated for total methylation (5mc + 5hmc; left plot) or 5-hmC levels (5hmc; right plot). E) Venn diagram showing the overlap of the human and rhesus probes with a median 5-hmC level > 20%.