FIGURE 8.
A novel primordial gene, logically related to modern gene expression. (Left) A simple, perhaps even monotonous, sequence in a small, primordial RNA (the archegene) expresses a phenotype by cross-templating a cofactor-like nucleotide RppA molecule, using an activated nucleotide with the primordial leaving group L. The archegene is the predecessor of a later, more evolved genetic system (the RNA Gene, center) which can perform RNA-catalyzed 3′–5′ coenzyme-RNA synthesis (center). Later yet, RNA world translation makes possible modern catalysts: coenzymes bound to peptides (from the Gene, on the right).
