The Prebiotic Chemistry of Alternative Nucleic Acids

Abstract

To adapt and survive, life as we know it must have a genetic component to pass on information accumulated during natural selection. It has been suggested that life may have begun with a self-replicating RNA molecule. This appears chemically untenable as the prebiotic synthesis of RNA was unlikely on the primitive Earth. It is now known that biological nucleic acids (DNA and RNA) are not chemically unique in their ability to serve as informational templates. Many structural isomers of nucleic acids are now known. Alternative genetic polymers that were more easily synthesized under plausible geochemical conditions may have preceded RNA. Despite some 50 years of research, many of the structural alterations of nucleic acids of possible relevance to the origin of life remain uninvestigated, though this may prove to be one of the most experimentally tractable areas in prebiotic chemistry. Various structures and the constraints posed by prebiotic chemistry are reviewed herein.