Clams May Hold the Secrets to a Longer Life, Scientists Claim

Could the secret to a longer life be hiding inside clams? Scientists think so.

In a new study from Italy's University of Bologna, researchers have discovered a group of genes that allow these creatures to live for hundreds of years, many of which may play a role in the aging of our own species.

"Longevity research can aim not only to extend human lifespan but also to increase the healthy period of life span and delay the development of diseases," Mariangela Iannello, a research fellow in the university's Department of Biological, Geological and Environmental Sciences, told Newsweek.

"[However,] so far many studies in the longevity field focused on the investigation of yeasts, fruit flies and worms," she said. "While such species offer in general many advantages in biology research—for example, they are easy handling and we know different aspects of their biology very well—they have a very short life span. Studying them for investigating longevity may be considered a paradox."

Studies in these animals have revealed that aging is largely driven by the accumulation of cellular damage over time. And much of this damage is caused by mutations in the genetic code, as well as a shortening of the protective caps at the ends of our DNA. But to understand how to slow this aging process, these short-lived animals are not the most helpful models.

"An alternative approach to better understanding the mechanisms responsible for the extension of longevity can be studying animals with particularly long life spans," Iannello said. "Some species evolved indeed the capability to live longer. The features that allow such longevity are encoded in their genomes, and the analysis of such features may help to identify key regulators that contribute to extension of life span."

Among these long-lived animals are the bivalve mollusks, a group of soft-bodied invertebrates surrounded by a two-part hinged shell. This group includes clams, oysters, mussels and scallops, among others.

"We know that bivalve mollusks include species with extreme longevity," Iannello said. "The most striking example is Arctica islandica, a clam species that can live more than 500 years. With such extraordinary life span, this species is the longest-lived non-colonial animal known so far. Despite that, the study of bivalves in the longevity field has been overlooked."

In their recent study, published in the journal Genome Biology and Evolution, Iannello and her team examined the DNA of four species of long-lived mollusk, including Arctica islandica, and compared these genes to those present in their short-lived relatives.

"The analysis of such interacting genes in their entirety is a new step toward a comprehensive characterization of the complex genetic pathways underlying longevity," Iannello said.

What they found was that many of the genetic variants present in the long-lived species were involved in the repair and maintenance of the animals' DNA.

"We found many genes involved in the repair of damages on DNA and in the maintenance of protein stability," Iannello said.

She continued: "This is interesting because the accumulation of errors in cells—due, for example, to an increased number of mutations in DNA and the accumulation of damaged proteins—is a primary hallmark of aging. We believe that genes that can contrast such error accumulation may have a central role in [delaying] aging and, therefore, extending lifespan.

An additional group of interesting genes the team found is involved in the control of cell proliferation, she said.

"Control of cell proliferation is a process of crucial importance in many organisms, as it prevents the proliferation of tumoral cells. Interestingly, tumors are rare in long-lived bivalves, and the genes we found may have a role in contrasting the insurgence of tumors in such species and consequently extending their life spans," Iannello said.

Interestingly, this is not the first time these genes have been implicated in longevity research.

"What I find the most exciting is that many genes in this network had been previously associated with longevity in other species," Iannello said. "This suggests that mechanisms involved in life span extension are shared across animals."

The widespread nature of these genes in long-lived animals provides useful clues into how our DNA controls our own longevity.

"We believe that this is an important result, as it reveals that we can take advantage of even very different species with extreme longevity to identify new genes and pathways that may have a role in regulating life span of other species, including humans," Iannello said.