In biology class you learned that DNA (deoxyribonucleic acid) is the main component of our genetic material and it is formed by combining four parts: A, C, G and T (adenine, cytosine, guanine and thymine), called bases of DNA. These bases combine in thousands of possible sequences to provide the genetic variability that enables the wealth of aspects and functions of living beings.
In the early 1980s, the four "classic" bases of DNA sort of got a fifth - methyl-cytosine (mC), derived from cytosine, which was later linked to epigenetic mechanisms because it is able to switch genes on or off depending on the physiological needs of each tissue.