Programmed Cell Death and Aging in Drosophila Melanogaster

Abstract

While a variety of theories regarding the etiology of aging have been proposed, they can be classified under two extreme models. One general model asserts that senescence is the result of attrition caused by normal “wear and tear”, that is the cumulative deleterious effects of environmental abuse and/or internal errors generated by all physical-chemical processes, with death as the inevitable result. At the other extreme is the model that posits aging as a normal part of the developmental process and therefore that at least in part, lifespan is genetically programmed. In their simplest form, neither model is absolutely correct, since aging, like any phenotype, must result from the sum of the interactions of environmental influences and genotype. The question is not whether genotype influences longevity; it certainly does. Rather, one might question whether lifespan is genetically programmed or not. Do genes exist whose principal, though not sole, role is to cause cell and organismal death? There is no strong evidence to support or reject the notion that such genes exist. Yet this hypothesis is testable.