Directed molecular evolution is a powerful tool to evolve genes with commer
cial applications. Its most common application is to evolve enzymes with im
proved kinetics, altered substrate or product specificities, or improved fu
nction in different cellular environments. The technique is beginning to be
applied to goals relevant to agriculture. Recent examples include the gene
ration of novel carotenoids, enhanced herbicide detoxification, and the imp
rovement of insect resistance genes.