Several lines of evidence strongly suggest that DNA methylation is involved in embryo
development. Perhaps the most direct evidence comes from experiments with
methyltransferase deficient mice. Embryos that express low levels of the maintenance
methyltransferase do not develop to term and die at the 5 to 20 somite stage corresponding
to the level of the enzyme. In the mouse, dramatic methylation changes have been observed
during the early steps of embryo development. Most genes are subject to a process of active …

Abstract Development from separate parental germ cells through fertilization and
proceeding to a fully functioning adult animal occurs through an intricate program of
transcriptional and chromatin changes. Epigenetic alterations such as DNA methylation are
an important part of this process. This review looks at the role of DNA methylation in early
embryonic development, as well as how this epigenetic mark affects stem cell differentiation
and tissue‐specific gene expression in somatic cells. Mol. Reprod. Dev. 77: 105–113, 2010 …