This research illustrates one of the many challenges associated with untangling genetic contributions to longevity; some of those genes affect personality traits that are also known to correlate with longevity:
A variant of a gene associated with active personality traits in humans seems to also be involved with living a longer life. [This] derivative 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 lifespan increases in mouse studies.
The variant gene is part of the dopamine system, which facilitates the transmission of signals among neurons and plays a major role in the brain network responsible for attention and reward-driven learning. The DRD4 7R allele blunts dopamine signaling, which enhances individuals' reactivity to their environment.
People who carry this variant gene [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, 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."