Another type of DNA damage is Base alkylation.

DNA base alkylation is one common consequence of multiple endogenous metabolic processes.

For example, alkylation can occur as a consequence of the non-enzymatic transfer of methyl groups to DNA from the universal methyl donor, S-adenosylmethionine.

For this type of damage, direct reversal repair will take place.

Direct reversal repair is a mechanism of repair where the damaged area or lesion is repaired directly by specialised proteins in our body. It is the simplest form of DNA repair and also, the most energy efficient method. It does not require a reference template unlike the other single-strand repair mechanism.