An expanded genetic alphabet

D.A. Malyshev, F.E. Romesberg, Angew. Chem. Int. Ed. (2015) 54:11930–11944.
pubpic2015malyshevNatural nucleic acids and the genetic information they encode are limited by the use of only four nucleotides that form two base pairs, (d)G-(d)C and d(A)-dT/U. In the past decade, three classes of unnatural base pairs have been developed to a high level of proof-of-concept. This review summarizes their development and the potentially revolutionary applications that they are now enabling.