title: The Effect of Post-Reproductive Lifespan on the Fixation Probability of Beneficial Mutations.
abstract: Post-reproductive lifespan is a common trait among mammals and is usually considered to be neutral; i.e. with no influence on population dynamics. Here, we explore the role of post-reproductive lifespan in the fixation probability of beneficial genetic variation. We compare two separate, stationary populations living in a constant environment that are equivalent except for the average time their respective members spend in the post-reproductive stage of life. Using a recently derived approximation, we show that fixation of a beneficial mutation is more likely in the population with greater post-reproductive longevity. This finding is surprising, as the population with more prolonged post-reproductive lifespan has smaller effective size and the classic population-genetic model would suggest that decreasing effective size reduces fixation chances of beneficial mutations. Yet, as we explain, in the age-structured case, when effective size gets smaller because of longer post-reproductive lifespan but census size is kept equal, a beneficial mutation has a higher likelihood to get fixed because it finds itself at higher initial frequency.
authors.affiliation: Max Planck Research Group: Modeling the Evolution of Aging, Max Planck Institute for Demographic Research, Rostock, Germany.
authors.forename: Stefano
authors.initials: S
authors.lastname: Giaimo
authors.affiliation: Max Planck Research Group: Modeling the Evolution of Aging, Max Planck Institute for Demographic Research, Rostock, Germany.
authors.forename: Annette
authors.initials: A
authors.lastname: Baudisch
mesh_terms: D000818:Animals; D005828:Genetics, Population / Q000379:methods; D008017:Life Expectancy; D008322:Mammals / Q000235:genetics; D009154:Mutation / Q000235:genetics*; D011156:Population Density; D011157:Population Dynamics; D011336:Probability; D012098:Reproduction / Q000235:genetics*