Correlation between the DNA methyltransferase (Dnmt) gene family and genome-wide 5-methylcytosine (5mC) in rotifer, copepod, and fish

DNA methyltransferases (DNMTs) are an enzyme family that catalyzes the transfer of a methyl group to DNA for a wide variety of biological functions. To determine whether the number and composition of the Dnmt gene family affects the 5-methylcytosine (5mc) ratio at the genome level, genome-wide 5mc ratios from three marine animals, the mangrove killifish (Kryptolebias marmoratus), an intertidal copepod (Tigriopus japonicus), and a monogonont rotifer (Brachionus koreanus), were analyzed in each organism after the cloning of Dnmt genes. Lineage- and teleost-specific gene evolution was observed in the vertebrate Dnmt3 gene family, while unique gene expansion was found in the T. japonicusDnmt1 gene family. However, the rotifer did not have any apparent homologue of Dnmt1 or Dnmt3 in its genome. This gene information was highly supportive of genome-wide 5mc levels in the three marine animals. Therefore, the absence or presence of the Dnmt gene family could be an important evolutionary parameter of how this could affect genome-wide epigenetic metabolism.