The Origin of the Ionized Linker: Geochemical Predestination for Phosphate?

Abstract

A major event in the origin of life on the earth must have been the formation of self-replicating polymers [e.g., Gilbert (Nature 319(6055):618, 1986)]. It is likely that any robust self-replicating polymer would have needed an ionized linker to slow hydrolysis and prevent diffusion. In modern life, the ionized linker is phosphate. In this chapter, I consider other alternatives to phosphate as linkers prior to the evolution of modern RNA/DNA. From a chemical and geological perspective phosphate is suggested to be the most likely molecule capable of performing the key activities of an ionized linker within a nucleic acid.