Los Angeles, Feb. 13 (Reuters): Scientists for the first time have identified a common genetic mutation in people over 100 years old, a finding they say could be a key to discovering a way to avoid the ravages of ageing.
In a study conducted at the California Institute of Technology in Pasadena, California, researchers found that centenarians were five times more likely than others to have the same mutation in their mitochondrial DNA.
Mitochondrial DNA, the portion of DNA located in the mitochondria or “powerhouses” of the cell, passes only from the mother to the offspring. The mitochondria capture the energy released from the oxidation of metabolites and convert them into energy.
“It is possible that in the process of replication these molecules are less damaged by oxidation, but we don’t know that yet,” said Dr. Guiseppe Attardi, Caltech professor of molecular biology, and an author of the study.
He said further lab studies are under way to determine the exact physiological effect of the genetic mutation.
The key mutation shifts the site at which mitochondrial DNA starts to replicate, and perhaps that may accelerate its replication, allowing the individual to replace damaged molecules faster, he said.
In the study of a group of 52 Italian centenarians, the researchers found a common mutation in the same main control region. Looking at mitochondrial DNA in white blood cells, they found that 17 per cent of the 52 had a specific mutation called C150T transition, compared with only 3.4 per cent of 117 people under the age of 99. The results are published in the latest issue of the Proceedings of the National Academy of Sciences.
To see whether the mutation is inherited, the team studied skin cells collected from the same individuals between nine and 19 years apart.
In some, both samples showed that the mutation already existed, while in others, it either appeared or became more abundant during the intervening years. These results suggest that some people inherit the mutation from their mother, while others acquire it during their lifetime, Attardi said.
“The selection of the C150T mutation in centenarians suggests that it may promote survival,” he said.