17. Do telomeres drive aging?

Telomere attrition can be a limiting factor in some tissues and species, especially where rapid cell turnover is required, but it does not define aging across the organism. Telomeres are one class of replicative constraint that can trigger dysfunction when critical thresholds are reached; however, many age-related failures occur in largely post-mitotic tissues and through mechanisms unrelated to telomere length. The rate of telomere shortening may help quantify aging, but it is not a universal clock.