There's no simple trick to reaching 100 years old, although most experts say it's a mix of luck and taking good care of yourself. Plus, it really helps to have one of the nineteen "longevity" gene groups scientists just discovered.
The experiment considered the genomes of 1,055 centenarians and 1,267 younger controls.The team, led by Paola Sebastiani and Thomas T. Perls of Boston University, zeroed in on particular areas of the genome that varied between the experimental and control groups. They were able to build a genetic model that could predict with 77% accuracy which genomes belonged to the centenarians and which belonged to their younger counterparts. They built the model by locating about 150 cases where a difference in a particular nucleotide in the genetic sequence - known as a single-nucleotide polymorphism - correlated with exceptional longevity.
Sebastiani puts their success in context:
"Seventy-seven percent is very high accuracy for a genetic model. But 23 percent error rate also shows there us a lot that remains to be discovered."
Additionally, the team was able to put ninety percent of the centenarians into one of nineteen different genetic clusters of various combinations of genotypes. Some of the clusters promoted longer survival (naturally enough), while others delayed the onset of disease. Indeed, a surprise for Sebastiani and Perls was the discovery that the centenarians had all the same genes that lead to age-related illnesses as their younger counterparts; they just happened to also possess genes that canceled these diseases out.
Perls explains the significance of this find:
"We have noted in previous work that 90 percent of centenarians are disability-free at the average age of 93. We had long hypothesized that to get to 100 you have to have a relative lack of disease-associated variants. But in this case, we're finding that not to be the case."
As for the super-centenarians, those 110 years old or more, they found that forty percent of this group had three particular gene clusters in common. Even though that's less than half the group, such a correlation provides another useful hint as to which areas of the genome play the biggest role in increased longevity.
Ultimately, Perls advises caution in reading too much into these findings, at least at the moment:
"We're quite a ways away, still, in understanding what pathways are governed by these genes. I look at the complexity of this puzzle and feel very strongly that this will not lead to treatments that will get people to be centenarians.
That said, the 77 percent success rate of their genetic model is way ahead of anything that's been accomplished before, and the team hopes to push forward with further research. This particular study has been going on since 1995 and focused on Caucasians. Perls and Sebastiani say they want to next run similar tests on Japanese centenarians, as Japan is well-known for its unusually large elderly population.
DNA sculpture by Bathsheba Grossman.