Figure 6.

Cross-replication and sustained exponential growth. (A) One round of cross-replication, beginning with 0.02 μM each of F1 (black) and F1′ (gray). The data were fit to the logistic growth equation, which gave an exponential growth rate of 0.11 min⁻¹ for both enzymes. Dashed vertical line indicates the yield at 45 min, which was the time of serial transfer. (B) Fifty successive rounds of cross- replication, with transfer of 1% of reacted materials (100-fold dilution) after each round. The yield of newly-synthesized F1 and F1′ was measured after each round and the compounded yield was plotted as a function of time, giving a growth rate of 2.67 logs/h⁻¹. Reaction conditions: 5 μM each substrate, 25 mM MgCl₂, pH 8.5, 47 °C.