5-methylcytosine (5mC) is a major epigenetic modification in animals.The programming and inheritance of parental DNA methylomes ensures the compatibility for totipotency and embryonic development.In vertebrates,the DNA methylomes of sperm and oocyte are significantly different.During early embryogenesis,the paternal and maternal methylomes will reset to the same state.We have shown that sperm (but not oocytes) methylome is inherited by zebrafish early embryos,and active demthylation occurs in both maternal and paternal genomes during the genome-wide demethylation in mammalian early embryos.Additionally,our data demonstrate that methylation programming can facilitate the early embryogenesis.