Error-prone DNA polymerase specifically involved in DNA repair (PubMed:11013228, PubMed:11387224). Plays an important role in translesion synthesis, where the normal high-fidelity DNA polymerases cannot proceed and DNA synthesis stalls (PubMed:11013228, PubMed:11387224, PubMed:14630940, PubMed:15199127, PubMed:20388628). Favors Hoogsteen base-pairing in the active site (PubMed:15254543). Inserts the correct base with high-fidelity opposite an adenosine template (PubMed:15254543). Exhibits low fidelity and efficiency opposite a thymidine template, where it will preferentially insert guanosine (PubMed:11013228). May play a role in hypermutation of immunoglobulin genes (PubMed:12410315). Forms a Schiff base with 5'- deoxyribose phosphate at abasic sites, but may not have lyase activity (PubMed:11251121, PubMed:14630940). {ECO:0000269|PubMed:11013228, ECO:0000269|PubMed:11251121, ECO:0000269|PubMed:11387224, ECO:0000269|PubMed:12410315, ECO:0000269|PubMed:14630940, ECO:0000269|PubMed:15199127, ECO:0000269|PubMed:15254543, ECO:0000269|PubMed:20388628}. This is the function of Ensembl gene identifier ENSG00000101751 (POLI, DNA polymerase iota).