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Walden N, Lucek K, Willi Y. Lineage‐specific adaptation to climate involves flowering time in North American
Arabidopsis lyrata. Mol Ecol 2020; 29:1436-1451. [DOI: 10.1111/mec.15338] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 11/16/2019] [Accepted: 12/10/2019] [Indexed: 01/06/2023]
Affiliation(s)
- Nora Walden
- Department of Environmental Sciences University of Basel Basel Switzerland
- Centre for Organismal Studies Heidelberg University of Heidelberg Heidelberg Germany
| | - Kay Lucek
- Department of Environmental Sciences University of Basel Basel Switzerland
| | - Yvonne Willi
- Department of Environmental Sciences University of Basel Basel Switzerland
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52
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Lucek K, Hohmann N, Willi Y. Postglacial ecotype formation under outcrossing and self-fertilization in Arabidopsis lyrata. Mol Ecol 2019; 28:1043-1055. [PMID: 30719799 DOI: 10.1111/mec.15035] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Revised: 01/18/2019] [Accepted: 01/28/2019] [Indexed: 12/01/2022]
Abstract
The formation of ecotypes has been invoked as an important driver of postglacial biodiversity, because many species colonized heterogeneous habitats and experienced divergent selection. Ecotype formation has been predominantly studied in outcrossing taxa, while far less attention has been paid to the implications of mating system shifts. Here, we addressed whether substrate-related ecotypes exist in selfing and outcrossing populations of Arabidopsis lyrata subsp. lyrata and whether the genomic footprint differs between mating systems. The North American subspecies colonized both rocky and sandy habitats during postglacial range expansion and shifted the mating system from predominantly outcrossing to predominantly selfing in a number of regions. We performed an association study on pooled whole-genome sequence data of 20 selfing or outcrossing populations, which suggested genes involved in adaptation to substrate. Motivated by enriched gene ontology terms, we compared root growth between plants from the two substrates in a common environment and found that plants originating from sand grew roots faster and produced more side roots, independent of mating system. Furthermore, single nucleotide polymorphisms associated with substrate-related ecotypes were more clustered among selfing populations. Our study provides evidence for substrate-related ecotypes in A. lyrata and divergence in the genomic footprint between mating systems. The latter is the likely result of selfing populations having experienced divergent selection on larger genomic regions due to higher genome-wide linkage disequilibrium.
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Affiliation(s)
- Kay Lucek
- Department of Environmental Sciences, University of Basel, Basel, Switzerland
| | - Nora Hohmann
- Department of Environmental Sciences, University of Basel, Basel, Switzerland
| | - Yvonne Willi
- Department of Environmental Sciences, University of Basel, Basel, Switzerland
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53
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Bélouard N, Paillisson J, Oger A, Besnard A, Petit EJ. Genetic drift during the spread phase of a biological invasion. Mol Ecol 2019; 28:4375-4387. [DOI: 10.1111/mec.15238] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 08/27/2019] [Accepted: 08/27/2019] [Indexed: 12/28/2022]
Affiliation(s)
- Nadège Bélouard
- UMR ECOBIO CNRS Université de Rennes 1 Rennes France
- UMR ESE Ecology and Ecosystem Health INRA, Agrocampus Ouest Rennes France
| | | | - Adrien Oger
- UMR ECOBIO CNRS Université de Rennes 1 Rennes France
| | - Anne‐Laure Besnard
- UMR ESE Ecology and Ecosystem Health INRA, Agrocampus Ouest Rennes France
| | - Eric J. Petit
- UMR ESE Ecology and Ecosystem Health INRA, Agrocampus Ouest Rennes France
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54
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Koski MH, Layman NC, Prior CJ, Busch JW, Galloway LF. Selfing ability and drift load evolve with range expansion. Evol Lett 2019; 3:500-512. [PMID: 31636942 PMCID: PMC6791181 DOI: 10.1002/evl3.136] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 08/09/2019] [Accepted: 08/11/2019] [Indexed: 12/16/2022] Open
Abstract
Colonization at expanding range edges often involves few founders, reducing effective population size. This process can promote the evolution of self-fertilization, but implicating historical processes as drivers of trait evolution is often difficult and requires an explicit model of biogeographic history. In plants, contemporary limits to outcrossing are often invoked as evolutionary drivers of self-fertilization, but historical expansions may shape mating system diversity, with leading-edge populations evolving elevated selfing ability. In a widespread plant, Campanula americana, we identified a glacial refugium in the southern Appalachian Mountains from spatial patterns of genetic drift among 24 populations. Populations farther from this refugium have smaller effective sizes and fewer rare alleles. They also displayed elevated heterosis in among-population crosses, reflecting the accumulation of deleterious mutations during range expansion. Although populations with elevated heterosis had reduced segregating mutation load, the magnitude of inbreeding depression lacked geographic pattern. The ability to self-fertilize was strongly positively correlated with the distance from the refugium and mutation accumulation-a pattern that contrasts sharply with contemporary mate and pollinator limitation. In this and other species, diversity in sexual systems may reflect the legacy of evolution in small, colonizing populations, with little or no relation to the ecology of modern populations.
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Affiliation(s)
- Matthew H Koski
- Department of Biology University of Virginia Charlottesville Virginia 22902.,Current Address: Department of Biological Sciences Clemson University Clemson SC 29631
| | - Nathan C Layman
- School of Biological Sciences Washington State University Pullman Washington 99164
| | - Carly J Prior
- School of Biological Sciences Washington State University Pullman Washington 99164
| | - Jeremiah W Busch
- School of Biological Sciences Washington State University Pullman Washington 99164
| | - Laura F Galloway
- Department of Biology University of Virginia Charlottesville Virginia 22902
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55
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Willi Y. The relevance of mutation load for species range limits. AMERICAN JOURNAL OF BOTANY 2019; 106:757-759. [PMID: 31162640 DOI: 10.1002/ajb2.1296] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Accepted: 03/26/2019] [Indexed: 06/09/2023]
Affiliation(s)
- Yvonne Willi
- Department of Environmental Sciences, University of Basel, 4056, Basel, Switzerland
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56
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Braasch J, Barker BS, Dlugosch KM. Expansion history and environmental suitability shape effective population size in a plant invasion. Mol Ecol 2019; 28:2546-2558. [PMID: 30993767 DOI: 10.1111/mec.15104] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 04/02/2019] [Accepted: 04/04/2019] [Indexed: 12/19/2022]
Abstract
The margins of an expanding range are predicted to be challenging environments for adaptation. Marginal populations should often experience low effective population sizes (Ne ) where genetic drift is high due to demographic expansion and/or census population size is low due to unfavourable environmental conditions. Nevertheless, invasive species demonstrate increasing evidence of rapid evolution and potential adaptation to novel environments encountered during colonization, calling into question whether significant reductions in Ne are realized during range expansions in nature. Here we report one of the first empirical tests of the joint effects of expansion dynamics and environment on effective population size variation during invasive range expansion. We estimate contemporary values of Ne using rates of linkage disequilibrium among genome-wide markers within introduced populations of the highly invasive plant Centaurea solstitialis (yellow starthistle) in North America (California, USA), and within native Eurasian populations. As predicted, we find that Ne within the invaded range is positively correlated with both expansion history (time since founding) and habitat quality (abiotic climate). History and climate had independent additive effects with similar effect sizes, indicating an important role for both factors in this invasion. These results support theoretical expectations for the population genetics of range expansion, though whether these processes can ultimately arrest the spread of an invasive species remains an unanswered question.
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Affiliation(s)
- Joseph Braasch
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, Arizona
| | - Brittany S Barker
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, Arizona.,Integrated Plant Protection Center and Department of Horticulture, Oregon State University, Corvallis, Oregon
| | - Katrina M Dlugosch
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, Arizona
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57
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Abstract
Factors that limit the geographic distribution of species are broadly important in ecology and evolutionary biology, and understanding distribution limits is imperative for predicting how species will respond to environmental change. Good data indicate that factors such as dispersal limitation, small effective population size, and isolation are sometimes important. But empirical research highlights no single factor that explains the ubiquity of distribution limits. In this article, we outline a guide to tackling distribution limits that integrates established causes, such as dispersal limitation and spatial environmental heterogeneity, with understudied causes, such as mutational load and genetic or developmental integration of traits limiting niche expansion. We highlight how modeling and quantitative genetic and genomic analyses can provide insight into sources of distribution limits. Our practical guide provides a framework for considering the many factors likely to determine species distributions and how the different approaches can be integrated to predict distribution limits using eco-evolutionary modeling. The framework should also help predict distribution limits of invasive species and of species under climate change.
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58
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Demastes JW, Hafner DJ, Hafner MS, Light JE, Spradling TA. Loss of genetic diversity, recovery and allele surfing in a colonizing parasite, Geomydoecus aurei. Mol Ecol 2019; 28:703-720. [PMID: 30589151 DOI: 10.1111/mec.14997] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Accepted: 12/17/2018] [Indexed: 02/07/2023]
Abstract
Understanding the genetic consequences of changes in species distributions has wide-ranging implications for predicting future outcomes of climate change, for protecting threatened or endangered populations and for understanding the history that has led to current genetic patterns within species. Herein, we examine the genetic consequences of range expansion over a 25-year period in a parasite (Geomydoecus aurei) that is in the process of expanding its geographic range via invasion of a novel host. By sampling the genetics of 1,935 G. aurei lice taken from 64 host individuals collected over this time period using 12 microsatellite markers, we test hypotheses concerning linear spatial expansion, genetic recovery time and allele surfing. We find evidence of decreasing allelic richness (AR) with increasing distance from the source population, supporting a linear, stepping stone model of spatial expansion that emphasizes the effects of repeated bottleneck events during colonization. We provide evidence of post-bottleneck genetic recovery, with average AR of infrapopulations increasing about 30% over the 225-generation span of time observed directly in this study. Our estimates of recovery rate suggest, however, that recovery has plateaued and that this population may not reach genetic diversity levels of the source population without further immigration from the source population. Finally, we employ a grid-based sampling scheme in the region of ongoing population expansion and provide empirical evidence for the power of allele surfing to impart genetic structure on a population, even under conditions of selective neutrality and in a place that lacks strong barriers to gene flow.
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Affiliation(s)
- James W Demastes
- Department of Biology, University of Northern Iowa, Cedar Falls, Iowa
| | - David J Hafner
- Museum of Southwestern Biology, University of New Mexico, Albuquerque, New Mexico
| | - Mark S Hafner
- Museum of Natural Science and Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana
| | - Jessica E Light
- Department of Wildlife and Fisheries Sciences, Texas A&M University, College Station, Texas
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Lee-Yaw JA, Zenni RD, Hodgins KA, Larson BMH, Cousens R, Webber BL. Range shifts and local adaptation: integrating data and theory towards a new understanding of species' distributions in the Anthropocene. THE NEW PHYTOLOGIST 2019; 221:644-647. [PMID: 30569613 DOI: 10.1111/nph.15554] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Affiliation(s)
- Julie A Lee-Yaw
- Department of Botany, University of British Columbia, 6270 University Blvd, Vancouver, BC, V6T 1Z4, Canada
| | - Rafael D Zenni
- Department of Biology, Federal University of Lavras, Av. Central, S/N Campus Universitário, Lavras, Minas Gerais, 37200-000, Brazil
| | - Kathryn A Hodgins
- School of Biological Sciences, Monash University, Clayton, Vic, 3800, Australia
| | - Brendon M H Larson
- School of Environment, Resources and Sustainability, University of Waterloo, 200 University Avenue W., Waterloo, ON, N2L 3G1, Canada
| | - Roger Cousens
- School of BioSciences, The University of Melbourne, Melbourne, Vic, 3010, Australia
| | - Bruce L Webber
- CSIRO Land and Water, Centre for Environment and Life Sciences, 147 Underwood Ave, Floreat, WA, 6014, Australia
- School of Biological Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, WA, 6009, Australia
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60
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Gilbert KJ, Peischl S, Excoffier L. Mutation load dynamics during environmentally-driven range shifts. PLoS Genet 2018; 14:e1007450. [PMID: 30265675 PMCID: PMC6179293 DOI: 10.1371/journal.pgen.1007450] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 10/10/2018] [Accepted: 08/29/2018] [Indexed: 11/29/2022] Open
Abstract
The fitness of spatially expanding species has been shown to decrease over time and space, but specialist species tracking their changing environment and shifting their range accordingly have been little studied. We use individual-based simulations and analytical modeling to compare the impact of range expansions and range shifts on genetic diversity and fitness loss, as well as the ability to recover fitness after either a shift or expansion. We find that the speed of a shift has a strong impact on fitness evolution. Fastest shifts show the strongest fitness loss per generation, but intermediate shift speeds lead to the strongest fitness loss per geographic distance. Range shifting species lose fitness more slowly through time than expanding species, however, their fitness measured at equal geographic distances from the source of expansion can be considerably lower. These counter-intuitive results arise from the combination of time over which selection acts and mutations enter the system. Range shifts also exhibit reduced fitness recovery after a geographic shift and may result in extinction, whereas range expansions can persist from the core of the species range. The complexity of range expansions and range shifts highlights the potential for severe consequences of environmental change on species survival.
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Affiliation(s)
- Kimberly J. Gilbert
- Institute of Ecology and Evolution, University of Bern, Bern, Switzerland
- Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Stephan Peischl
- Swiss Institute of Bioinformatics, Lausanne, Switzerland
- Interfaculty Bioinformatics Unit, University of Bern, Bern, Switzerland
| | - Laurent Excoffier
- Institute of Ecology and Evolution, University of Bern, Bern, Switzerland
- Swiss Institute of Bioinformatics, Lausanne, Switzerland
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61
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Bonchev G, Willi Y. Accumulation of transposable elements in selfing populations of Arabidopsis lyrata supports the ectopic recombination model of transposon evolution. THE NEW PHYTOLOGIST 2018; 219:767-778. [PMID: 29757461 DOI: 10.1111/nph.15201] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 04/01/2018] [Indexed: 06/08/2023]
Abstract
Transposable elements (TE) can constitute a large fraction of plant genomes, yet our understanding of their evolution and fitness effect is still limited. Here we tested several models of evolution that make specific predictions about differences in TE abundance between selfing and outcrossing taxa, and between small and large populations. We estimated TE abundance in multiple populations of North American Arabidopsis lyrata differing in mating system and long-term size, using transposon insertion display on several TE families. Selfing populations had higher TE copy numbers per individual and higher TE allele frequencies, supporting models which assume that selection against TEs acts predominantly against heterozygotes via the process of ectopic recombination. In outcrossing populations differing in long-term size, the data supported neither a model of density-regulated transposition nor a model of direct deleterious effect. Instead, the population structure of TEs revealed that outcrossing populations tended to split into western and eastern groups - as previously detected using microsatellite markers - whereas selfing populations from west and east were less differentiated. This, too, agrees with the model of ectopic recombination. Overall, our results suggest that TE elements are nearly neutral except for their deleterious potential to disturb meiosis in the heterozygous state.
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Affiliation(s)
- Georgi Bonchev
- Institute of Biology, Evolutionary Botany, University of Neuchâtel, Neuchâtel, 2000, Switzerland
- Institute of Plant Physiology and Genetics, Laboratory of Genome Dynamics and Stability, Bulgarian Academy of Sciences, Sofia, 1113, Bulgaria
| | - Yvonne Willi
- Institute of Biology, Evolutionary Botany, University of Neuchâtel, Neuchâtel, 2000, Switzerland
- Department of Environmental Sciences, University of Basel, Basel, 4056, Switzerland
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