The frequency of fitness peak shifts is increased at expanding range margins due to mutation surfing

Olivia J. Burton, Justin M. J. Travis

Research output: Contribution to journalArticle

33 Citations (Scopus)

Abstract

Dynamic species' ranges, those that are either invasive or shifting in response to environmental change, are the focus of much recent interest in ecology, evolution, and genetics. Understanding how range expansions can shape evolutionary trajectories requires the consideration of nonneutral variability and genetic architecture, yet the majority of empirical and theoretical work to date has explored patterns of neutral variability. Here we use forward computer simulations of population growth, dispersal, and mutation to explore how range-shifting dynamics can influence evolution on rugged fitness landscapes. We employ a two-locus model, incorporating sign epistasis, and find that there is an increased likelihood of fitness peak shifts during a period of range expansion. Maladapted valley genotypes can accumulate at an expanding range front through a phenomenon called mutation surfing, which increases the likelihood that a mutation leading to a higher peak will occur. Our results indicate that most peak shifts occur close to the expanding front. We also demonstrate that periods of range shifting are especially important for peak shifting in species with narrow geographic distributions. Our results imply that trajectories on rugged fitness landscapes can be modified substantially when ranges are dynamic.

Original languageEnglish
Pages (from-to)941-950
Number of pages10
JournalGenetics
Volume179
Issue number2
DOIs
Publication statusPublished - Jun 2008

Keywords

  • genetic diversity
  • large populations
  • sign epistasis
  • species range
  • wave-front
  • evolution
  • evolvability
  • dispersal
  • perspective
  • adaptation

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