Also, GNMT, the glycine N-methyltransferase that transforms S-Adenosyl methionine (SAM) to S-adenosylhomocysteine (SAH) and thereby donates a methyl group, and DNMT1, the DNA (cytosine-5-)-methyltransferase 1 that transfers the released methyl group to CpG residues of target DNAs, were both up-regulated in oocytes derived from polycystic ovaries of gilts, indicating abnormally activated one-carbon metabolic pathway and modified DNA methylation process. This evidence concerns the gene GNMT and polycystic ovary syndrome.