title: The genetic signature of rapid range expansions: How dispersal, growth and invasion speed impact heterozygosity and allele surfing.
abstract: As researchers collect spatiotemporal population and genetic data in tandem, models that connect demography and dispersal to genetics are increasingly relevant. The dominant spatiotemporal model of invasion genetics is the stepping-stone model which represents a gradual range expansion in which individuals jump to uncolonized locations one step at a time. However, many range expansions occur quickly as individuals disperse far from currently colonized regions. For these types of expansion, stepping-stone models are inappropriate. To more accurately reflect wider dispersal in many organisms, we created kernel-based models of invasion genetics based on integrodifference equations. Classic theory relating to integrodifference equations suggests that the speed of range expansions is a function of population growth and dispersal. In our simulations, populations that expanded at the same speed but with spread rates driven by dispersal retained more heterozygosity along axes of expansion than range expansions with rates of spread that were driven primarily by population growth. To investigate surfing we introduced mutant alleles in wave fronts of simulated range expansions. In our models based on random mating, surfing alleles remained at relatively low frequencies and surfed less often compared to previous results based on stepping-stone simulations with asexual reproduction.
authors.affiliation: Department of Biological Sciences, CW 405, Biological Sciences Bldg., University of Alberta, Edmonton, Alberta, Canada T6G 2E9. Electronic address: goodsman@ualberta.ca.
authors.forename: Devin W
authors.initials: DW
authors.lastname: Goodsman
authors.affiliation: Canadian Forest Service, Northern Forestry Centre, 5320 122 Street Northwest, Edmonton, Alberta, Canada T6H 3S5. Electronic address: Barry.Cooke@NRCan-RNCan.gc.ca.
authors.forename: Barry
authors.initials: B
authors.lastname: Cooke
authors.affiliation: Department of Biological Sciences, CW 405, Biological Sciences Bldg., University of Alberta, Edmonton, Alberta, Canada T6G 2E9. Electronic address: dcoltman@ualberta.ca.
authors.forename: David W
authors.initials: DW
authors.lastname: Coltman
authors.affiliation: Department of Biological Sciences, CW 405, Biological Sciences Bldg., University of Alberta, Edmonton, Alberta, Canada T6G 2E9; Mathematical and Statistical Sciences, 632 CAB, University of Alberta, Edmonton, Alberta, Canada T6G 2G1. Electronic address: mark.lewis@ualberta.ca.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Lewis
mesh_terms: D000465:Algorithms; D000483:Alleles; D000818:Animals; D003198:Computer Simulation; D003710:Demography / Q000379:methods; D014644:Genetic Variation; D005828:Genetics, Population / Q000379:methods*; D019656:Loss of Heterozygosity / Q000235:genetics*; D008957:Models, Genetic; D015233:Models, Statistical; D009154:Mutation; D011157:Population Dynamics; D012098:Reproduction / Q000235:genetics*; D012100:Reproduction, Asexual / Q000235:genetics
keywords: Dispersal; Genetic diversity; Heterozygosity; Invasion; Range expansion