Table 1. Perturbation of the coding regime by mismatches.

e	ΔΔG0 (kcal mol−1)
1	0	0.7739	0.8347	0.061
0.7226	0.2	0.7825	0.8434	0.061
0.1	1.417	0.8225	0.8443	0.022
0.01	2.834	0.8334	0.8360	0.003
0	very large	0.8347	0.8347	0

Numerical results with a = 10², b = 1; c = 10⁻², d = 10⁻¹ (for which Σ≈0.8347). The ΔΔG₀ indicated is the free-energy difference between the weakest complementary interaction (codon II) and the mismatch. A value of e = 0.7226 implies a ΔΔG₀ of 0.2 kcal mol⁻¹, which is the approximate difference between AU (Watson-Crick) and GU (Wobble) base-pairs [20].