Learning From Nature: How Mole Rats And Beavers Achieve Exceptional Lifespans

Getting your Trinity Audio player ready...

Researchers studied the genomes of the two longest-lived rodent species: the naked mole-rat and Canadian beaver.
Both species appear have evolved common mechanisms of lifespan extension in the form of enhanced resistance to DNA damage and cellular stress.
Genes affecting energy and fatty acid metabolism were the most strongly selected for during evolution.

Species that are closely related on the evolutionary tree can differ greatly in average lifespan. A naked mole rat is genetically much closer to a guinea pig than to a dog, yet can live to over 35 – over twice as long as most dogs will. How and why evolution has selected for exceptional longevity in certain species is a mystery that, if solved, could help us control longevity in humans.

To better understand the genetic and molecular factors that control longevity, this study compared the genomes of the two longest-lived rodents: the naked mole rat and the Canadian beaver. The findings suggest these species have evolved similar means of lifespan extension.

The average lifespans of beavers and naked mole-rats greatly exceed those of their genetic neighbours.

Using genetic sequencing data, they were able to score molecular pathways for how strongly they were selected for during evolution. They found that the highest scoring pathways that were shared between the two species were related to energy production and lipid metabolism. For example, the electron transport chain in the mitochondria (in which the cell’s energy is produced) was a major driver of selection in both species. In general, conserved genes involved protection from oxidative stress and DNA damage.

Lipid metabolism and energy metabolism in general are thought to play an important role in the ageing process. Damage caused by byproducts of these pathways – such as reactive oxygen species – eventually outstrip a cell’s repair abilities, causing it to enter a state of dormancy called senescence. The fact that the two longest-lived rodents both independently acquired mutations to protect against this kind of damage is further evidence that these processes are important in the ageing process.

Studying the genomes of long-lived rodents and other animals may help us to discover genetic factors involved in lifespan control.