N-6-Methyl-2-deoxyadenosine (m6dA) is an adenine nucleoside analogue. N-6-Methyl-2-deoxyadenosine targets nuclear processes and DNA replication machineries including WER, SATB1, TFAM, Jumu, SSBP1, DNA polymerase eta and phage polymerase Gp90 exo-. N-6-Methyl-2-deoxyadenosine acts as a multifunctional epigenetic regulator that modulates transcription, DNA damage response, cell cycle, transposon silencing, stress adaptation, epigenetic crosstalk, and nucleosome organization in both prokaryotes and eukaryotes. N-6-Methyl-2-deoxyadenosine regulates mitochondrial epigenetic inheritance and is required for fear extinction memory in mice. N-6-Methyl-2-deoxyadenosine exhibits dysregulated levels in cancers. N-6-Methyl-2-deoxyadenosine can be used for the research of glioblastoma, triple negative breast cancer, and conditioned fear (fear extinction impairment)[1][2].