Evolution over time of the concentrations of 1 and 16 in non-irradiated libraries prepared from 1, with no dyes added, in the same conditions as in Fig. 4a (left panel) or Fig. 4b (right panel). The top halves of the graphs show the concentration of 1 (black squares) and 16 (red squares, in units of 1). The bottom halves of the graphs represent the oxidation (black circles) and replication (red circles) rates in the system, calculated by numerical differentiation of the curves in the top halves.