According to Perls, centenarians could have different types of genetic characteristics underlying their extreme old age: they may lack the mutations that make some people more susceptible to the diseases of aging, such as Alzheimer’s and heart disease. They may also possess variations that protect against these diseases, or even longevity-enhancing genes, which actually slow the aging process.
“I think it’s unlikely there is going to be a single powerful gene for the fountain of youth,” Perls says. “It’s like the lottery in that you need six or seven numbers to win. Each is relatively common, but getting them all together is rare.”
It’s not yet clear if the Methuselah Project will be successful. If each of the genes responsible for healthy aging exerts only a modest effect, the 100 person project may be too small to pick them out. Genes that exert a modest effect on disease risk or other factors are much more difficult to identify than those that guarantee that the bearer will develop the disease, as is the case with Huntington’s. Most gene-chip studies have required hundreds to thousands of people to identify genetic variants linked to complex diseases.
Rothberg isn’t too concerned about his relatively small sample size at this point. He emphasizes that the first stage of the project is to test his new approach to sequencing. And as sequencing costs continue to fall, additional centenarians can be added to the pool. Fortunately, new members join this club of lucky lottery winners every day.