New research suggests a genetic variant that accompanies active personality traits in humans also appears to be associated with living a longer life.
In a series of mouse studies, UC Irvine researchers and others discovered that an offshoot of a dopamine-receptor gene — called the DRD4 7R allele — appears in significantly higher rates in people more than 90 years old and is linked to life-span increases in mouse studies.
Robert Moyzis, Ph.D., professor of biological chemistry at UC Irvine, and Nora Volkow, M.D., a psychiatrist who conducts research at the Brookhaven National Laboratory, led the research effort. Findings are online in The Journal of Neuroscience.
Researchers say the variant gene is part of the dopamine system, a network which facilitates the transmission of signals among neurons and plays a major role in the brain network responsible for attention and reward-driven learning.
Investigators say the DRD4 7R allele moderates dopamine signaling, which enhances individuals’ reactivity to their environment.
People who carry this variant gene, Moyzis said, seem to be more motivated to pursue social, intellectual and physical activities. The variant is also linked to attention-deficit/hyperactivity disorder and addictive and risky behaviors.
“While the genetic variant may not directly influence longevity,” Moyzis said, “it is associated with personality traits that have been shown to be important for living a longer, healthier life.
“It’s been well documented that the more you’re involved with social and physical activities, the more likely you’ll live longer. It could be as simple as that.”
Numerous studies — including a number from the 90+ Study — have confirmed that being active is important for successful aging, and it may slow the advance of neurodegenerative diseases, such as Alzheimer’s.
Prior molecular evolutionary research indicated that this “longevity allele” was selected for during the nomadic out-of-Africa human exodus more than 30,000 years ago.
In the new study, the UC Irvine team analyzed genetic samples from 310 participants in the 90+ Study.
This “oldest-old” population had a 66 percent increase in individuals carrying the variant relative to a control group of 2,902 people between the ages of 7 and 45. The presence of the variant also was strongly correlated with higher levels of physical activity.
Next, Volkow, neuroscientist Panayotis Thanos, Ph.D., and colleagues found that mice without the variant had a 7 percent to 9.7 percent decrease in lifespan compared with those possessing the gene, even when raised in an enriched environment.
While it’s evident that the variant can contribute to longevity, Moyzis said further studies must take place to identify any immediate clinical benefits from the research.
“However, it is clear that individuals with this gene variant are already more likely to be responding to the well-known medical adage to get more physical activity,” he added.