Washington: In a new study, scientists have suggested that if you alter you genes to have a longer lifespan, it doesn't necessarily mean that it would be a healthier one too.
A study of long-lived mutant C. elegans by scientists at the University of Massachusetts Medical School shows that the genetically altered worms spend a greater portion of their life in a frail state and exhibit less activity as they age then typical nematodes.
Principal investigator of the study Heidi A. Tissenbaum, PhD, said that to find the genes that help people remain physically active during ageing, they may have to look beyond longevity as the sole criteria, and start looking at new genes that might play a part in 'healthspan.'
Dr. Tissenbaum and colleagues sought to investigate how healthy long-lived C. elegans mutants were as they aged.
Identifying both frailty and movement as measureable physical attributes that declined in the nematode with age and that could be tested, Ankita Bansal, PhD, , took four different C. elegans mutant specimen (daf-2, eat-2, ife-2 and clk-1) known to live longer than typical nematodes and measured their resistance to heat stress, oxidative stress and activity levels on solids and in liquids as they aged.
They compared these results with wild-type nematodes they found that all the animals-wild-type and mutants-declined physically as they aged. And depending on the mutant specimen and trait being measured, each declined at different rates. Overall they found that the mutant worms, despite having longer lifespans, spent a greater percentage of their lives at less than 50 percent of measured maximum function when compared to wild-type nematodes. The increased lifespan experienced by the mutants was spent, instead, in a frail and debilitated state.
The results are published in the Proceedings of the National Academy of Sciences.