Aging and Genomic Instability
Ouroboros looks at recent longevity research in the context of DNA damage and other genomic instability - a good follow-on to a recent post on that subject at Fight Aging!: "Earlier this week we learned that mutations in the kinase SCH9, combined with intervention in the RAS and TOR pathways, can extend the chronological lifespan of yeast by as much as tenfold. ... Mutation of SCH9, which extends lifespan on its own, suppresses the longevity-shortening phenotype of SGS1 deletion. Since calorie restriction (CR) has no effect on chromosomal rearrangements in the SGS1 mutants, this study has parsed the contributions of SCH9 and CR to at least one molecular correlate of aging (specifically, genome stability). The authors argue that their results further demonstrate the importance of genome stability to the aging process, a point on which certain researchers focusing on mammalian aging would agree. The question remains, however: Does genomic instability shorten lifespan by increasing transcriptional noise, as suggested by the Vijg lab's stochasticity experiments, or via another mechanism?" A good question indeed. The precise relationship between damage to the genome and aging is up for debate.
Link: http://ouroboros.wordpress.com/2008/01/18/longevity-mutation-suppresses-genome-instability/