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Studying Age-dependent Genomic Instability using the S. cerevisiae Chronological Lifespan Model
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A computer model of the evolution of specific maximum lifespan
Mechanisms of Ageing and Development
|May 1, 1981
Summary
Organisms evolve finite lifespans due to natural selection acting on maximum lifespan, which plateaus as environmental changes and reproduction rates increase. This evolutionary model explains lifespan limits without requiring external lifespan-shortening factors.
Area of Science:
- Evolutionary biology
- Theoretical biology
- Genetics
Background:
- Organisms exhibit finite and specific maximum lifespans, a phenomenon not fully explained by evolutionary theory.
- Existing hypotheses suggest lifespan limits arise from a balance between selection and lifespan-decreasing processes.
Purpose of the Study:
- To investigate the evolutionary mechanisms driving the development of finite and specific maximum lifespans in organisms.
- To determine if natural selection alone can explain the evolution of limited lifespans.
Main Methods:
- Development and experimental study of a discrete-event simulation model for lifespan evolution.
- Analysis of natural selection's effect on maximum lifespan under varying niche fluctuations and fecundity.
Main Results:
- The simulation model evolved a plateau in maximum lifespan, influenced by niche fluctuations and fecundity.
- This plateau results from natural selection's diminishing rate of increasing maximum lifespan, approaching zero as lifespan increases.
- Group selection was ruled out as the cause for the observed lifespan plateau.
Conclusions:
- Finite and specific maximum lifespans can evolve through natural selection without necessarily invoking external lifespan-shortening processes.
- The study supports hypotheses involving weak selection equilibrium but suggests a more general counter-process: a bias in genetic drift toward shorter lifespans.
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