In the Microbial Genome Program, scientists are altering the genome of the bacterium Deinococcus radiodurans to increase its potential usefulness in cleaning up toxic-waste sites around the globe. Studies have revealed that the microbe's extraordinary DNA-repair processes enable it to thrive in high-radiation environments. Through the use of biotechnological processes, scientists hope to add genes from other organisms that will confer the ability to degrade toxic chemicals such as toluene, commonly found in mixed, chemical, and radiation waste sites.

Other examples of current and potential applications of genetic engineering follow.

• Production of pharmaceuticals by bacteria that produce human insulin for diabetics or human growth hormone for individuals with dwarfism. Scientists are perfecting ways to transfer human genes for important proteins into cows, sheep, and goats to obtain medically significant products from the milk of these animals.

• Development of diagnostics to detect disease-causing organisms and monitor the safety of food and water supplies. Investigators also are developing systems for identifying pathogens that may someday be used as biological weapons by rogue nations or even terrorist groups.

• Use of bacteria as living sensors (biosensors) of particular chemicals in soil, air, and water. In some studies, bacteria have been genetically altered to emit a green fluorescent protein visible in ultraviolet light when they metabolize the explosive TNT leaking from land mines. Researchers envision a day when bacteria can be applied to a tract of land with a crop duster and then analyzed from a helicopter.