Mammalian Pol ι owns an unusual combination of properties: it is stimulated by Mn2+ ions, can bypass some DNA lesions and misincorporates ¡°G¡± opposite template ¡°T¡± more frequently than incorporates the correct ¡°A.¡± It also was shown to possess dRP lyase activity. In addition, Pol ι is much more efficient in the presence of Mn2+ in comparison to Mg2+. . It has been proposed that POLI involves in immunoglobulin somatic hypermutation (SHM), bypass of deaminated cytosines, several adducts of the purine bases. DNA strand crosslinks and is involved in DNA repair under oxidative stress.