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In 1983 scientists discovered a bacterial gene, CP4, which encodes for a highly efficient, glyphosate-resistant form of EPSPS (Padgette et al., 1996a). Using the new, gene-based methods of biotechnology, crop developers were able to deliver the Agrobacterium CP4 gene into crop plants. As a result, biotech crops contain both the glyphosate-susceptible form of EPSPS, encoded by crop genes, and the glyphosate-resistant EPSPS encoded by the microbial CP4 gene. Having the bacterial form of EPSPS allows crops to continue to synthesize aromatic amino acids, even as the plant EPSPS enzyme is inactivated by glyphosate competitive inhibition, because glyphosate does not bind to bacterial EPSPS. The bacterial CP4 gene provides the basis of glyphosate resistance in most biotech crops that are resistant to the herbicide.