FIG. 2.

Typical DNA demethylation and remethylation in the NANOG promoter during porcine early embryogenesis. The sperm DNA was highly methylated (A) whereas MII oocytes were hypomethylated (B). The paternal genome was actively demethylated with the overall 4.03% methylation at 4-cell stage (C). The DNA hypomethylation continued until the blastocyst stage (D). The subsequent de novo methylation rendered somatic tissue with a high level of DNA methylation (E).