EVOLUTIONARY BIOLOGISTS have produced the most satisfying explanations for why aging occurs in humans and other age-structured populations. The idea, reduced to its simplest form, is that we age because of a variety of gene actions that escape the force of natural selection. I have recently suggested a new classification of the types of gene actions that escape these forces, including "good" alleles that are the substrate for the evolution for decreased rates of aging and enhanced longevity.1 These gene actions are dynamic and plastic, however; given a sufficient number of generations and a continuation of the current trends in our developed societies to postpone the ages of reproduction, one may anticipate the gradual emergence of modified life histories, with longer life spans for Homo sapiens. I speculate, however, that there will be an intermediate period of increasing mutational loads, perhaps with the emergence of novel late-onset diseases of aging.
Martin GM. The Evolutionary Substrate of Aging. Arch Neurol. 2002;59(11):1702-1705. doi:10.1001/archneur.59.11.1702