Dear Professor, please excuse me if my comment merely shows my ignorance on the subject. The position of seniority in evolutionary age of the mitochondrial system along with it's being incorporated into and acceptance by so many different organisms tells a story of ubiquitous success. Its a well established, a settled in, a widely accepted, very old system that has stood up to all the evolutionary challenges so far. I acknowledge it's capable of getting sick and developing nasty mutations. Besides when such things might affect it, I can't see a reason to suspect that it plays a major role in aging, but who knows, it might. Genetics is definitely the right field to be in, but there's more than one tree to be barked up. Take for instance the bristlecone pine (Pinus longaeva) and a regular pine. The only thing that sets them apart from each other is the difference that exists in their genetics. Somewhere within that bulk of different code, are held the recipes / keys to its extraordinary longevity as compared with more regular pines. I suppose since you are looking at mitochondria, you might do well to compare the mitochondrial sequences so to capture the differences between that of Pinus longaeva and the other shorter lived pine species. That might provide interesting results much sooner than the ROS hypothesis. I'm not sure which if any may have been sequenced to date. If none have, then I guess it would be a good place to start trying to uncover new information. I hope you make lots more interesting discoveries. Wishing you the best of luck!