DNA N6-methyladenine: a new epigenetic mark in eukaryotes?

DNA N-6-adenine methylation (N-6-methyladenine; 6mA) in prokaryotes functions primarily in the host defence system. The prevalence and significance of this modification in eukaryotes had been unclear until recently. Here, we discuss recent publications documenting the presence of 6mA in Chlamydomonas reinhardtii, Drosophila melanogaster and Caenorhabditis elegans; consider possible roles for this DNA modification in regulating transcription, the activity of transposable elements and transgenerational epigenetic inheritance; and propose 6mA as a new epigenetic mark in eukaryotes.