6mA is formed by transferring methyl groups to the 6th position of the adenine ring catalyzed by methyl-transferases. It is a non-canonical DNA modification that is present at low levels in different eukaryotes. 6mA possesses similar characteristics between prokaryotes and eukaryotes. Its functions display diversity, such as guiding the discrimination between original and newly synthesized DNA strand after replication, regulating gene transcription and repressing transposable elements; in the cell cycle, reducing the stability of base pairings for opening DNA duplexes. Strikingly, the protection from methylation is an inherited state that, however, can be modified by environmental conditions.