Figure 10

Evolution of early codes by selecting on the ATP yield. Evolution of the assignation of amino acids to adapters by selecting on the resulting ATP yield. (A) Employing only the simplest four Miller amino acids (alanine, aspartic acid, glycine and valine) 104 runs with initial random associations converged to optimise the ATP yield, in all cases reaching to the maximum of 2 moles of ATP. (B) 100 runs started from random associations to alanine and glycine and every 7000 generations a new Miller amino acid, randomly selected, was included and assigned to a random adapter. Most runs converged to optimal codes (with the maximum yield of 3 moles of ATP), but three did not.