Aging in a statistical sense is the increasing probability of death with increasing time of an organism’s existence (1, 2). Can we extrapolate this to self-regenerating tissues and most particularly to the stem cells that drive the replenishment of lost and damaged cells throughout life? To be succinct, how close is the linkage between the vitality of the stem cell population and organismal
longevity? These questions are currently without clear answers and thenature of the linkage, if any, is likely to be complicated, but is nonetheless conceptually compelling.