Fuente: WIPO "tomato" Described herein are cytidine deaminases and methods of use of such cytidine deaminases. Also described herein are complexes, compositions, and systems including polypeptides of the present invention, each of which may be used for modifying and/or editing a target nucleic acid. Further described herein are cytosine base editors and methods of use of such cytosine base editors including in a method of modifying and/or editing a target nucleic acid.