Four-year-old baby bull elephant „Num Choke“ kneels in front of a group of brides and grooms during their wedding ceremony in the northern Thai province of Ayutthaya, 80 km (50 miles) from Bangkok on February 14, 2003. A group of 14 couples took their wedding vows seated on the backs of elephants to mark Valentines Day. PHOTO - REUTERS

LOS ANGELES - 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 aging. 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 mitochrondrial DNA. Mitochondrial DNA, the portion of DNA located in the mitochondria or „powerhouses“ of the cell, passes only from the mother to offspring. The mitochondria capture the energy released from the oxidation of metabolites and convert it into energy.

Dr. Guiseppe Attardi, Caltech professor of molecular biology, and an author of the study, said lab studies are underway 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 percent of the 52 had a specific mutation called C150T transition, compared with only 3.4 percent of 117 people under the age of 99.

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. Reuters