Charting a dynamic DNA methylation landscape of the human genome
Nature (2013) doi:10.1038/nature12433
Ziller at al looked at 42 whole genome bisulfite sequence datasets from 30 cell-lines and tissues (which seems indicative of the practice of not having biological replicates for WGBS).
When requring a difference of 30% (FDR 0.104), they find only 5.6million CpGs in 716K regions with "dynamic" methylation and use this to