The average level of methylation varies between organisms—the worm Caenorhabditis elegans lacks cytosine methylation, while vertebrates have higher levels, with up to 1% of their DNA containing 5-methylcytosine.
Det gennemsnitlige methyleringsniveau varierer mellem organismer – ormen Caenorhabditis elegans har ingen cytosinmethylering, mens hvirveldyr har højere niveauer, med 5-methylcytosin i op til 1% af deres DNA .