The activation induced deaminase is a vertebrate-specific member of the classical AID/APOBEC cytosine deaminases that is involved in antibody diversification [1].

1: Evolution of the deaminase fold and multiple origins of eukaryotic editing and mutagenic nucleic acid deaminases from bacterial toxin systems. Iyer LM, Zhang D, Rogozin IB, Aravind L; Nucleic Acids Res. 2011; [Epub ahead of print] PMID:21890906

2: Diversification of AID/APOBEC-like deaminases in metazoa: multiplicity of clades and widespread roles in immunity. Krishnan A, Iyer LM, Holland SJ, Boehm T, Aravind L; Proc Natl Acad Sci U S A. 2018;115:E3201. PMID:29555751

3: DNA deamination in immunity: AID in the context of its APOBEC relatives. Conticello SG, Langlois MA, Yang Z, Neuberger MS; Adv Immunol. 2007;94:37-73. PMID:17560271