5-methylcytosine (5mC) is an epigenetic modification to DNA which modulates transcription. 5mC might be sequentially oxidized to 5-hydroxymethylcytosine (5hmC), 5-formylcytosine (5fC) and 5-carboxylcytosine (5caC). Collectively, these marks are known as the oxidized derivatives of 5mC (i.e., oxi-mCs). Their formation is
