where t ‡ and t rxn are set to 180 kJ/mol and 1.0 kJ/g, respectively. The GA search starts with an initial population of 100 randomly generated genes of singly substituted molecules, for which the scores are computed using the linear regression models. Pairs of genes are then selected with a probability proportional to their score (roulette selection) and mated, by choosing a random cut point between bases for two parent genes and recombining. After each mating a mutation is performed 20% of the time by randomly changing one of the bases. This process is repeated 100 times and the 100 best scoring genes before and after mating is selected as the new population and the process is repeated for 100 generations.