The dynamic changes of DNA methylation in primordial germ cell differentiation

•The latest researches on methylation and demethylation events in the early embryo•Essential stages for mammalian development•Hydroxymethylation, significant components of dynamic methylation regulation.

The discovery of DNA methylation has provided a new perspective on how DNA may be dynamically regulated in the mammalian genome. DNA methylation is a dynamic process with a demethylation and de novo methylation from primordial germ cell to differentiation. DNA methylation and demethylation have been proposed to play important roles in somatic cell reprogramming. Some essential components were discussed, such as hydroxymethylation which has recently been confirmed as a modification of developmental importance.