Reply to Wilkinson: Minor role of programmed methylation and demethylation in mammalian development

Wilkinson (1) does not dispute any of our (2) main claims: that CpG-dense promoters are unmethylated in all tissues and CpG-poor promoters are variably methylated and undergo transcription factor-induced demethylation after activation; that global genome demethylation in cells and tissues does not cause ectopic expression of tissue-specific genes; and that there is little convincing evidence of a biochemical system that performs programmed...