Exploiting Natural Variation in Life Span to Evaluate Mechanisms of Aging

Abstract

A 40,000-fold variation exists in maximum longevity across the animal kingdom. Even among mammals, naturally occurring differences in maximum life span among similar-sized species far exceed experimental life-span exten- sion induced by genetic manipulations and/or caloric restriction. Elucidating mechanisms of different aging rates and of concomitant disparate longevity among different species of similar body composition, biochemistry, and physiology may provide new insights into aging and may also be used to test the ubiquity of find- ings reported with traditional models. As such, studies employing a comparative approach to aging are poised to make pivotal inroads leading to understanding the mechanisms of aging.