Epigenetic modifications, DNA methylation in particular, regulate key developmental processes, including germ cell imprinting, stem cell maintenance/differentiation, and play a crucial role in the early periods of embryogenesis (Bartolomei, 2003; Kiefer, 2007; Kondo, 2006; Surani et al., 2007). DNA methylation is also a fundamental aspect of programmed fetal development, determining cell fate, pattern formation, terminal differentiation and maintenance of cellular memory required for developmental stability (Cavalli, 2006; Kafri et al., 1992). Moreover, aberrant epigenetic changes in response to environmental stimuli have been shown to contribute to developmental disorders (Zhao et al., 2007).
