The Essence of Aging.

The idea that aging is a purposeful, programmed series of events is intuitively appealing based on its many conserved aspects and the demonstrated feasibility of modifying life span by manipulating single genes or pathways. Yet, the case for a nonadaptive basis of aging is strong and now all but generally accepted in the field. Here, we briefly review why the case for programmed aging is weak, with a focus on the lack of possible evolutionary beneficial effects.