( ited States the machine can sort about...)Fluorescing lab worms signal longer life spans

Genetic testing on both the bright and dim worms revealed that the levels of the green fluorescent protein expressed by parent worms were not passed down to offspring and therefore not heritable, said Rea.

Research suggests that humans possess several similar types of "stress-response" systems tuned to counter environmental insults like oxidative stress, pathogens, alcohol and heat, said Rea. Some of the stress-response systems appear to overlap with each other, while others operate completely independently, he said.

"We suspect several different biomarkers exist that represent the many different stress-response systems present in an organism," Rea said. "By finding them, we should ultimately be able to find what makes an animal robust to many different insults."

Johnson authored a milestone paper in 1988 showing that mutating a single gene in roundworms could double their life span -- the first evidence that the lifespan of an animal could be increased by genetic alteration. Since then, researchers around the world have been tinkering with proteins and genes of C. elegans in attempts to understand more about how life span can be increased.

Although interventions involving pharmaceuticals and other treatments clearly have a substantial effect on human longevity, many believe that the primary key to longer and healthier lives may involve genetic manipulation, said Rea. "But genes and environment are not the entire answer," he said. "Clearly, there is a large component of chance."

In the future, scientists could conceivably analyze human fluid samples for a variety of biomarkers similar to HSP-16 in order to determine a person's life span, said Rea. "They might even be able to tweak each stress-response system and set them for maximum longevity, which is believed to be about 120 years."