The emergence of proto-mRNAs and proto-rRNAs. (a) A C-DRT would lose those subsequences between its proto-tRNA binding sites (see Figure 2e) and transform into a "proto-mRNA". (b) The emergence of the proto-ss-rRNA (the small dotted-line box) would aid the binding between the proto-tRNAs and the proto-mRNA, allowing the reduction of the base pairs between them, with an ultimate outcome likely to be the triplet anticodon/codon pairs. The large recognition loop of proto-tRNAs would degenerate into a small "anticodon loop". (c) The emergence of proto-ls-rRNA (the large dotted-line box) would restrict the amino acids adjacent in a more rigid way, thus favoring the formation of peptide bonds. Note: the "aa-delivering arms" of the proto-tRNAs are drawn with an angle backwards from the present plane.