MANY VARIABLES. “The identification of longevity-related genes does not explain the mechanisms of healthy aging and longevity rather pose questions on epigenetic contribution, gene regulation and the interactions with essential genomes, i.e. mitochondrial DNA and microbiota. To fully disentangle what appears to be an endless quest, all the components of the complexity of human longevity genetics are taken into account.”
http://www.ingentaconnect.com/content/ben/cvp/2014/00000012/00000005/art00007