Prebiotic Synthesis of Nucleotides

If an RNA-only world preceded more complex forms oflife, then it is essential that the process wherebythe first nucleotides were made be considered. Presumably there were no enzymes and no templates tofacilitate the synthesis of the first nucleotides soanother form of chemical evolution must have beeninvolved. Answers to problems of this sort weresought vigorously in the 1960s and the early 1970s butmany issues were left unresolved. Progress made inthe last few years has added to this early work andbrings us closer to a satisfactory solution. In thisarticle key results, old and new, and some ideas as tohow further progress is likely to be made are discussed.There are reasons for optimism. Substantial progresshas been made on the synthesis of purines and ribose,phosphorylation and polyphosphorylation. Theoutstanding problems at this juncture relate to thesynthesis of ribose to the exclusion of the otheraldopentoses and to the problem of linking ribose tothe purine bases.