Researchers at Salk Institute for Biological Studies demonstrate for the first time that the roundworm Caenorhabditis elegans succumbs to the trials of old age although its telomeres are still long, and moves with a youthful spring in its crawl despite short telomeres, they report in PLoS Genetics, available online now.
In the past, preventing telomere shortening has often been portrayed as the key to preventing aging and living longer. In their study, Salk scientists Jan Karlseder, an assistant professor in the Regulatory Biology Laboratory, and Andrew Dillin, an assistant professor in the Molecular and Cell Biology Laboratory, provide a much more nuanced view of telomeres and the process of cellular and organismal aging.
"Some long-lived species like humans have telomeres that are much shorter than the telomeres in species like mice, which live only a few years. Nobody yet knows why. But now we have conclusive evidence that telomeres alone do not dictate aging and lifespan," says Karlseder.
Each time a cell divides, its telomeres get shorter, a process called replicative or cellular aging. Some have likened this progressive erosion of telomeres to a genetic biological clock that winds down over time, leading to a gradual decline in our mental and physical prowess. Yet, C. elegans, a tiny creature, which spends the better part of its adult life without a single dividing cell in its body, still shows signs of old age and eventually dies, raising intriguing questions.
Are telomeres in non-dividing cells eroding slowly over time? If so, will worms with longer telomeres live longer? If not, how do worm cells and by extension non-dividing human cells, such as nerve cells, keep track of their biol