title: Empirical verification of evolutionary theories of aging.
abstract: We recently selected 3 long-lived mutant strains ofSaccharomyces cerevisiaeby a lasting exposure to exogenous lithocholic acid. Each mutant strain can maintain the extended chronological lifespan after numerous passages in medium without lithocholic acid. In this study, we used these long-lived yeast mutants for empirical verification of evolutionary theories of aging. We provide evidence that the dominant polygenic trait extending longevity of each of these mutants 1) does not affect such key features of early-life fitness as the exponential growth rate, efficacy of post-exponential growth and fecundity; and 2) enhances such features of early-life fitness as susceptibility to chronic exogenous stresses, and the resistance to apoptotic and liponecrotic forms of programmed cell death. These findings validate evolutionary theories of programmed aging. We also demonstrate that under laboratory conditions that imitate the process of natural selection within an ecosystem, each of these long-lived mutant strains is forced out of the ecosystem by the parental wild-type strain exhibiting shorter lifespan. We therefore concluded that yeast cells have evolved some mechanisms for limiting their lifespan upon reaching a certain chronological age. These mechanisms drive the evolution of yeast longevity towards maintaining a finite yeast chronological lifespan within ecosystems.
authors: Department of Biology, Concordia University, Montreal, Quebec H4B 1R6, Canada.
authors: Pavlo
authors: P
authors: Kyryakov
authors: Department of Biology, Concordia University, Montreal, Quebec H4B 1R6, Canada.
authors: Alejandra
authors: A
authors: Gomez-Perez
authors: Department of Biology, Concordia University, Montreal, Quebec H4B 1R6, Canada.
authors: Anastasia
authors: A
authors: Glebov
authors: Department of Biology, Concordia University, Montreal, Quebec H4B 1R6, Canada.
authors: Nimara
authors: N
authors: Asbah
authors: Department of Biology, Concordia University, Montreal, Quebec H4B 1R6, Canada.
authors: Luigi
authors: L
authors: Bruno
authors: Department of Biology, Concordia University, Montreal, Quebec H4B 1R6, Canada.
authors: Carolynne
authors: C
authors: Meunier
authors: Department of Biology, Concordia University, Montreal, Quebec H4B 1R6, Canada.
authors: Tatiana
authors: T
authors: Iouk
authors: Department of Biology, Concordia University, Montreal, Quebec H4B 1R6, Canada.
authors: Vladimir I
authors: VI
authors: Titorenko
mesh_terms: D000375:Aging; D005075:Biological Evolution; D005838:Genotype; D008095:Lithocholic Acid / Q000494:pharmacology*; D009154:Mutation; D030781:Organisms, Genetically Modified; D012441:Saccharomyces cerevisiae / Q000187:drug effects* / Q000235:genetics
chemical_list: D008095:Lithocholic Acid
keywords: aging; ecosystems; evolution; longevity; yeast