For the best experience, open this PDF portfolio in Acrobat 9 or Adobe Reader 9, or later. Get Adobe Reader Now! Suicide Genes © Josh Mitteldorf A1: Disposable Soma 299 APPENDIX ONE +##-Versions of the Disposable Soma Theory #-Sha

One of the ways that the evolutionary theory of aging has survived in the face of contravening evidence is that it shifts shape. I have characterized the field in terms of three main theories (Mutation Accumulation (MA), Antagonistic Pleiotropy (AP) and Disposable Soma (DS)), and within these there are variations and interpretations. More than the others, the DS theory is associated with a single theorist, Tom Kirkwood, but in different writing and at different times, he has characterized the DS theory variously. This multiplicity of theories is itself a problem. The fact that aging appeared early in the history of life, and that genes for aging have been preserved and spread almost universally over a billion years of evolution suggests that aging has a fundamental evolutionary purpose. The story may turn out to be more complicated, but certainly it would be fitting and satisfying to find a single theory that applies similarly across a wide swath of the biosphere. There are four basic versions of the Disposable Soma theory. Proponents of the theory apply the most expeditious version in each experimental situation, and nowhere are the versions clearly distinguished. The four versions are based on either metabolic tradeoffs or genetic tradeoffs; and the tradeoffs either involve allocation of energy or of other unspecified ‘resources’. A genetic tradeoff in implies a fixed strategy, programmed into the genes over evolutionary time, dictating the body’s energy usage in pre-determined proportions, regardless of present circumstances. A metabolic tradeoff is unfolding within an individual’s lifetime, depending on actual (as opposed to potential) allocation of energy. As an illustration of the difference, consider that both hypotheses would predict an inverse correlation between fertility and longevity for animals in the wild. But suppose a genetically homogeneous group of rodent