1
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Dunning LT, Olofsson JK, Papadopulos AST, Hibdige SGS, Hidalgo O, Leitch IJ, Baleeiro PC, Ntshangase S, Barker N, Jobson RW. Hybridisation and chloroplast capture between distinct Themeda triandra lineages in Australia. Mol Ecol 2022; 31:5846-5860. [PMID: 36089907 PMCID: PMC9828686 DOI: 10.1111/mec.16691] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 09/07/2022] [Accepted: 09/09/2022] [Indexed: 01/13/2023]
Abstract
Ecotypes are distinct populations within a species that are adapted to specific environmental conditions. Understanding how these ecotypes become established, and how they interact when reunited, is fundamental to elucidating how ecological adaptations are maintained. This study focuses on Themeda triandra, a dominant grassland species across Asia, Africa and Australia. It is the most widespread plant in Australia, where it has distinct ecotypes that are usually restricted to either wetter and cooler coastal regions or the drier and hotter interior. We generate a reference genome for T. triandra and use whole genome sequencing for over 80 Themeda accessions to reconstruct the evolutionary history of T. triandra and related taxa. Organelle phylogenies confirm that Australia was colonized by T. triandra twice, with the division between ecotypes predating their arrival in Australia. The nuclear genome provides evidence of differences in the dominant ploidal level and gene-flow among the ecotypes. In northern Queensland there appears to be a hybrid zone between ecotypes with admixed nuclear genomes and shared chloroplast haplotypes. Conversely, in the cracking claypans of Western Australia, there is cytonuclear discordance with individuals possessing the coastal chloroplast and interior clade nuclear genome. This chloroplast capture is potentially a result of adaptive introgression, with selection detected in the rpoC2 gene which is associated with water use efficiency. The reason that T. triandra is the most widespread plant in Australia appears to be a result of distinct ecotypic genetic variation and genome duplication, with the importance of each depending on the geographic scale considered.
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Affiliation(s)
- Luke T. Dunning
- Ecology and Evolutionary Biology, School of BiosciencesUniversity of SheffieldSheffieldUK
| | - Jill K. Olofsson
- Section for Forest, Nature and Biomass, Department of Geosciences and Natural Resource ManagementUniversity of CopenhagenFrederiksberg CDenmark
| | | | - Samuel G. S. Hibdige
- Ecology and Evolutionary Biology, School of BiosciencesUniversity of SheffieldSheffieldUK
| | - Oriane Hidalgo
- Royal Botanic GardensSurreyUK,Institut Botànic de Barcelona (IBB), CSIC‐Ajuntament de BarcelonaBarcelonaSpain
| | | | - Paulo C. Baleeiro
- Department of Biological ScienceThe University of QueenslandSt LuciaQueenslandAustralia
| | | | - Nigel Barker
- Department of Plant and Soil SciencesUniversity of PretoriaHatfieldSouth Africa
| | - Richard W. Jobson
- National Herbarium of New South Wales, Australian Institute of Botanical ScienceSydneyNew South WalesAustralia
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2
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Mitchell N, Luu H, Owens GL, Rieseberg LH, Whitney KD. Hybrid evolution repeats itself across environmental contexts in Texas sunflowers (Helianthus). Evolution 2022; 76:1512-1528. [PMID: 35665925 PMCID: PMC9544064 DOI: 10.1111/evo.14536] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 05/05/2022] [Accepted: 05/09/2022] [Indexed: 01/22/2023]
Abstract
To what extent is evolution repeatable? Little is known about whether the evolution of hybrids is more (or less) repeatable than that of nonhybrids. We used field experimental evolution in annual sunflowers (Helianthus) in Texas to ask the extent to which hybrid evolution is repeatable across environments compared to nonhybrid controls. We created hybrids between Helianthus annuus (L.) and H. debilis (Nutt.) and grew plots of both hybrids and nonhybrid controls through eight generations at three sites in Texas. We collected seeds from each generation and grew each generation × treatment × home site combination at two final common gardens. We estimated the strength and direction of evolution in terms of fitness and 24 traits, tested for repeated versus nonrepeated evolution, and assessed overall phenotypic evolution across lineages and in relation to a locally adapted phenotype. Hybrids consistently evolved higher fitness over time, while controls did not, although trait evolution varied in strength across home sites. Repeated evolution was more evident in hybrids versus nonhybrid controls, and hybrid evolution was often in the direction of the locally adapted phenotype. Our findings have implications for both the nature of repeatability in evolution and the contribution of hybridization to evolution across environmental contexts.
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Affiliation(s)
- Nora Mitchell
- Department of BiologyUniversity of New MexicoAlbuquerqueNew MexicoUSA,Department of BiologyUniversity of Wisconsin – Eau ClaireEau ClaireWisconsinUSA
| | - Hoang Luu
- Department of Environmental and Plant BiologyOhio UniversityAthensOhioUSA
| | - Gregory L. Owens
- Department of BiologyUniversity of VictoriaVictoriaBritish ColumbiaCanada
| | - Loren H. Rieseberg
- Department of Botany and Biodiversity Research CentreUniversity of British ColumbiaBritish ColumbiaCanada
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3
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Wang Z, Jiang Y, Yang X, Bi H, Li J, Mao X, Ma Y, Ru D, Zhang C, Hao G, Wang J, Abbott RJ, Liu J. Molecular signatures of parallel adaptive divergence causing reproductive isolation and speciation across two genera. Innovation (N Y) 2022; 3:100247. [PMID: 35519515 PMCID: PMC9065898 DOI: 10.1016/j.xinn.2022.100247] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 04/16/2022] [Indexed: 11/18/2022] Open
Abstract
Parallel evolution of reproductive isolation (PERI) provides strong evidence for natural selection playing a fundamental role in the origin of species. However, PERI has been rarely demonstrated for well established species drawn from different genera. In particular, parallel molecular signatures for the same genes in response to similar habitat divergence in such different lineages is lacking. Here, based on whole-genome sequencing data, we first explore the speciation process in two sister species of Carpinus (Betulaceae) in response to divergence for temperature and soil-iron concentration in habitats they occupy in northern and southwestern China, respectively. We then determine whether parallel molecular mutations occur during speciation in this pair of species and also in another sister-species pair of the related genus, Ostryopsis, which occupy similarly divergent habitats in China. We show that gene flow occurred during the origin of both pairs of sister species since approximately 9.8 or approximately 2 million years ago, implying strong natural selection during divergence. Also, in both species pairs we detected concurrent positive selection in a gene (LHY) for flowering time and in two paralogous genes (FRO4 and FRO7) of a gene family known to be important for iron tolerance. These changes were in addition to changes in other major genes related to these two traits. The different alleles of these particular candidate genes possessed by the sister species of Carpinus were functionally tested and indicated likely to alter flowering time and iron tolerance as previously demonstrated in the pair of Ostryopsis sister species. Allelic changes in these genes may have effectively resulted in high levels of prezygotic reproductive isolation to evolve between sister species of each pair. Our results show that PERI can occur in different genera at different timescales and involve similar signatures of molecular evolution at genes or paralogues of the same gene family, causing reproductive isolation as a consequence of adaptation to similarly divergent habitats. PERI provides strong evidence for natural selection playing a fundamental role in the origin of species PERI is rarely demonstrated for well-established species drawn from different genera We detected PERI across two genera (Carpinus and Ostryopsis) in the family Betulaceae PERI can occur in different genera at different timescales and involve molecular signatures at similar pathways
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Affiliation(s)
- Zefu Wang
- State Key Laboratory of Grassland Agro-Ecosystem, College of Ecology, Lanzhou University, Lanzhou 730000, China
- Key Laboratory for Bio-resource and Eco-environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, China
| | - Yuanzhong Jiang
- Key Laboratory for Bio-resource and Eco-environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, China
| | - Xiaoyue Yang
- State Key Laboratory of Grassland Agro-Ecosystem, College of Ecology, Lanzhou University, Lanzhou 730000, China
| | - Hao Bi
- Key Laboratory for Bio-resource and Eco-environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, China
| | - Jialiang Li
- Key Laboratory for Bio-resource and Eco-environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, China
| | - Xingxing Mao
- Key Laboratory for Bio-resource and Eco-environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, China
| | - Yazhen Ma
- Key Laboratory for Bio-resource and Eco-environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, China
| | - Dafu Ru
- State Key Laboratory of Grassland Agro-Ecosystem, College of Ecology, Lanzhou University, Lanzhou 730000, China
| | - Cheng Zhang
- Key Laboratory for Bio-resource and Eco-environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, China
- Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China
| | - Guoqian Hao
- Sichuan Tea College, Yibin University, Yibin 644000, China
| | - Jing Wang
- Key Laboratory for Bio-resource and Eco-environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, China
| | | | - Jianquan Liu
- State Key Laboratory of Grassland Agro-Ecosystem, College of Ecology, Lanzhou University, Lanzhou 730000, China
- Key Laboratory for Bio-resource and Eco-environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, China
- Corresponding author
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4
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James ME, Arenas-Castro H, Groh JS, Allen SL, Engelstädter J, Ortiz-Barrientos D. Highly Replicated Evolution of Parapatric Ecotypes. Mol Biol Evol 2021; 38:4805-4821. [PMID: 34254128 PMCID: PMC8557401 DOI: 10.1093/molbev/msab207] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Parallel evolution of ecotypes occurs when selection independently drives the evolution of similar traits across similar environments. The multiple origins of ecotypes are often inferred based on a phylogeny that clusters populations according to geographic location and not by the environment they occupy. However, the use of phylogenies to infer parallel evolution in closely related populations is problematic because gene flow and incomplete lineage sorting can uncouple the genetic structure at neutral markers from the colonization history of populations. Here, we demonstrate multiple origins within ecotypes of an Australian wildflower, Senecio lautus. We observed strong genetic structure as well as phylogenetic clustering by geography and show that this is unlikely due to gene flow between parapatric ecotypes, which was surprisingly low. We further confirm this analytically by demonstrating that phylogenetic distortion due to gene flow often requires higher levels of migration than those observed in S. lautus. Our results imply that selection can repeatedly create similar phenotypes despite the perceived homogenizing effects of gene flow.
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Affiliation(s)
- Maddie E James
- School of Biological Sciences, The University of Queensland,St. Lucia, QLD, Australia
| | - Henry Arenas-Castro
- School of Biological Sciences, The University of Queensland,St. Lucia, QLD, Australia
| | - Jeffrey S Groh
- School of Biological Sciences, The University of Queensland,St. Lucia, QLD, Australia
| | - Scott L Allen
- School of Biological Sciences, The University of Queensland,St. Lucia, QLD, Australia
| | - Jan Engelstädter
- School of Biological Sciences, The University of Queensland,St. Lucia, QLD, Australia
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5
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Pflugbeil G, Affenzeller M, Tribsch A, Comes HP. Primary hybrid zone formation in Tephroseris helenitis (Asteraceae), following postglacial range expansion along the central Northern Alps. Mol Ecol 2021; 30:1704-1720. [PMID: 33548078 PMCID: PMC8048512 DOI: 10.1111/mec.15832] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 01/26/2021] [Accepted: 01/27/2021] [Indexed: 11/26/2022]
Abstract
Distinguishing between secondary versus primary hybrid zone formation remains a challenging task as, for instance, the time window in which these historical (vicariant) versus contemporary (environmental-selective) processes are distinguishable may be relatively narrow. Here, we examine the origin and structure of a transition zone between two subspecies of Tephroseris helenitis along the central Northern Alps, using molecular (AFLP) and morphological (achene type) data in combination with ecological niche models (ENMs) to hindcast ranges at the Last Glacial Maximum (LGM) and mid-Holocene. Samples were collected over a c. 350 km long transect, largely covered by ice during the LGM. Genetically nonadmixed individuals of subspp. helenitis versus salisburgensis dominated the westernmost versus eastern transect areas, with admixed individuals occurring in between. Clines for achene morphology and outlier loci potentially under climate-driven selection were steep, largely noncoincidental, and displaced to the east of the cline centre for neutral AFLPs. During the LGM, ssp. helenitis should have been able to persist in a refugium southwest of the transect, while suitable habitat for ssp. salisburgensis was apparently absent at this time. Together with patterns of genetic and clinal variation, our ENM data are suggestive of a primary hybrid zone that originated after the species' postglacial, eastward expansion. The observed clinal changes may thus reflect random/nonadaptive processes during expansion and selection on particular loci, and possibly achene type, in response to a long-term, west-to-east climate gradient in the direction of more stressful (e.g., wetter/cooler) conditions. Overall, this study adds to the vast hybrid zone literature a rare example of a hybrid zone caused by primary differentiation within a plant species, underlaid by historical range expansion.
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Affiliation(s)
- Georg Pflugbeil
- Department of Biosciences, University of Salzburg, Salzburg, Austria
| | | | - Andreas Tribsch
- Department of Biosciences, University of Salzburg, Salzburg, Austria
| | - Hans Peter Comes
- Department of Biosciences, University of Salzburg, Salzburg, Austria
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6
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Konečná V, Yant L, Kolář F. The Evolutionary Genomics of Serpentine Adaptation. FRONTIERS IN PLANT SCIENCE 2020; 11:574616. [PMID: 33391295 PMCID: PMC7772150 DOI: 10.3389/fpls.2020.574616] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/20/2020] [Accepted: 11/23/2020] [Indexed: 06/12/2023]
Abstract
Serpentine barrens are among the most challenging settings for plant life. Representing a perfect storm of hazards, serpentines consist of broadly skewed elemental profiles, including abundant toxic metals and low nutrient contents on drought-prone, patchily distributed substrates. Accordingly, plants that can tolerate the challenges of serpentine have fascinated biologists for decades, yielding important insights into adaptation to novel ecologies through physiological change. Here we highlight recent progress from studies which demonstrate the power of serpentine as a model for the genomics of adaptation. Given the moderate - but still tractable - complexity presented by the mix of hazards on serpentine, these venues are well-suited for the experimental inquiry of adaptation both in natural and manipulated conditions. Moreover, the island-like distribution of serpentines across landscapes provides abundant natural replicates, offering power to evolutionary genomic inference. Exciting recent insights into the genomic basis of serpentine adaptation point to a partly shared basis that involves sampling from common allele pools available from retained ancestral polymorphism or via gene flow. However, a lack of integrated studies deconstructing complex adaptations and linking candidate alleles with fitness consequences leaves room for much deeper exploration. Thus, we still seek the crucial direct link between the phenotypic effect of candidate alleles and their measured adaptive value - a prize that is exceedingly rare to achieve in any study of adaptation. We expect that closing this gap is not far off using the promising model systems described here.
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Affiliation(s)
- Veronika Konečná
- Department of Botany, Faculty of Science, Charles University, Prague, Czechia
- Institute of Botany, The Czech Academy of Sciences, Pru˚honice, Czechia
| | - Levi Yant
- Future Food Beacon and School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Filip Kolář
- Department of Botany, Faculty of Science, Charles University, Prague, Czechia
- Institute of Botany, The Czech Academy of Sciences, Pru˚honice, Czechia
- Natural History Museum, University of Oslo, Oslo, Norway
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7
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Yamaguchi R, Otto SP. Insights from Fisher's geometric model on the likelihood of speciation under different histories of environmental change. Evolution 2020; 74:1603-1619. [DOI: 10.1111/evo.14032] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 05/25/2020] [Accepted: 05/30/2020] [Indexed: 02/02/2023]
Affiliation(s)
- Ryo Yamaguchi
- Department of Advanced Transdisciplinary SciencesHokkaido University Sapporo Hokkaido 060‐0810 Japan
- Department of Biological SciencesTokyo Metropolitan University Hachioji Tokyo 192‐0397 Japan
| | - Sarah P. Otto
- Department of Zoology & Biodiversity Research CentreUniversity of British Columbia Vancouver BC V6T 1Z4 Canada
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8
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Duchen P, Hautphenne S, Lehmann L, Salamin N. Linking micro and macroevolution in the presence of migration. J Theor Biol 2019; 486:110087. [PMID: 31758967 DOI: 10.1016/j.jtbi.2019.110087] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 10/06/2019] [Accepted: 11/18/2019] [Indexed: 01/26/2023]
Abstract
Understanding macroevolutionary patterns is central to evolutionary biology. This involves the process of divergence within a species, which starts at the microevolutionary level, for instance, when two subpopulations evolve towards different phenotypic optima. The speed at which these optima are reached is controlled by the degree of stabilising selection, which pushes the mean trait towards different optima in the different subpopulations, and ongoing migration that pulls the mean phenotype away from that optimum. Traditionally, macro phenotypic evolution is modelled by directional selection processes, but these models usually ignore the role of migration within species. Here, our goal is to reconcile the processes of micro and macroevolution by modelling migration as part of the speciation process. More precisely, we introduce an Ornstein-Uhlenbeck (OU) model where migration happens between two subpopulations within a branch of a phylogeny and this migration decreases over time as it happens during speciation. We then use this model to study the evolution of trait means along a phylogeny, as well as the way phenotypic disparity between species changes with successive epochs. We show that ignoring the effect of migration in sampled time-series data biases significantly the estimation of the selective forces acting upon it. We also show that migration decreases the expected phenotypic disparity between species and we analyse the effect of migration in the particular case of niche filling. We further introduce a method to jointly estimate selection and migration from time-series data. Our model extends traditional quantitative genetics results of selection and migration from a microevolutionary time frame to multiple speciation events at a macroevolutionary scale. Our results further support that not accounting for gene flow has important consequences in inferences at both the micro and macroevolutionary scale.
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Affiliation(s)
- Pablo Duchen
- Department of Computational Biology, University of Lausanne, Lausanne, Switzerland.
| | - Sophie Hautphenne
- School of Mathematics and Statistics, University of Melbourne, Melbourne, Australia; Institute of Mathematics, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Laurent Lehmann
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
| | - Nicolas Salamin
- Department of Computational Biology, University of Lausanne, Lausanne, Switzerland
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9
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Cai Z, Zhou L, Ren NN, Xu X, Liu R, Huang L, Zheng XM, Meng QL, Du YS, Wang MX, Geng MF, Chen WL, Jing CY, Zou XH, Guo J, Chen CB, Zeng HZ, Liang YT, Wei XH, Guo YL, Zhou HF, Zhang FM, Ge S. Parallel Speciation of Wild Rice Associated with Habitat Shifts. Mol Biol Evol 2019; 36:875-889. [PMID: 30861529 PMCID: PMC6501882 DOI: 10.1093/molbev/msz029] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The occurrence of parallel speciation strongly implies the action of natural selection. However, it is unclear how general a phenomena parallel speciation is since it was only shown in a small number of animal species. In particular, the adaptive process and mechanisms underlying the process of parallel speciation remain elusive. Here, we used an integrative approach incorporating population genomics, common garden, and crossing experiments to investigate parallel speciation of the wild rice species Oryza nivara from O. rufipogon. We demonstrated that O. nivara originated multiple times from different O. rufipogon populations and revealed that different O. nivara populations have evolved similar phenotypes under divergent selection, a reflection of recurrent local adaptation of ancient O. rufipogon populations to dry habitats. Almost completed premating isolation was detected between O. nivara and O. rufipogon in the absence of any postmating barriers between and within these species. These results suggest that flowering time is a “magic” trait that contributes to both local adaptation and reproductive isolation in the origin of wild rice species. Our study thus demonstrates a convincing case of parallel ecological speciation as a consequence of adaptation to new environments.
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Affiliation(s)
- Zhe Cai
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Lian Zhou
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Ning-Ning Ren
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Xun Xu
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Rong Liu
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing, China
| | - Lei Huang
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing, China
| | - Xiao-Ming Zheng
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing, China
| | - Qing-Lin Meng
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Yu-Su Du
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Mei-Xia Wang
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Mu-Fan Geng
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Wen-Li Chen
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing, China
| | - Chun-Yan Jing
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Xin-Hui Zou
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Jie Guo
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing, China
| | - Cheng-Bin Chen
- Guangxi Academy Agricultural Sciences, Nanning, Guangxi, China
| | - Hua-Zhong Zeng
- Guangxi Academy Agricultural Sciences, Nanning, Guangxi, China
| | - Yun-Tao Liang
- Guangxi Academy Agricultural Sciences, Nanning, Guangxi, China
| | - Xing-Hua Wei
- State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, China
| | - Ya-Long Guo
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Hai-Fei Zhou
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing, China
| | - Fu-Min Zhang
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Song Ge
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
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10
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Oke KB, Motivans E, Quinn TP, Hendry AP. Sexual dimorphism modifies habitat‐associated divergence: Evidence from beach and creek breeding sockeye salmon. J Evol Biol 2018; 32:227-242. [DOI: 10.1111/jeb.13407] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 11/17/2018] [Accepted: 11/20/2018] [Indexed: 12/13/2022]
Affiliation(s)
- Krista B. Oke
- Department of Biology and Redpath Museum McGill University Montreal Quebec Canada
- College of Fisheries and Ocean Sciences University of Alaska Fairbanks Juneau Alaska
| | - Elena Motivans
- Department of Biology and Redpath Museum McGill University Montreal Quebec Canada
- Helmholtz Centre for Environmental Research Leipzig Germany
| | - Thomas P. Quinn
- School of Aquatic and Fishery Sciences University of Washington Seattle Washington
| | - Andrew P. Hendry
- Department of Biology and Redpath Museum McGill University Montreal Quebec Canada
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11
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Thompson KA, Rieseberg LH, Schluter D. Speciation and the City. Trends Ecol Evol 2018; 33:815-826. [DOI: 10.1016/j.tree.2018.08.007] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Revised: 08/18/2018] [Accepted: 08/22/2018] [Indexed: 12/30/2022]
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12
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Yoichi W, Kawamata I, Matsuki Y, Suyama Y, Uehara K, Ito M. Phylogeographic analysis suggests two origins for the riparian azalea Rhododendron indicum (L.) Sweet. Heredity (Edinb) 2018; 121:594-604. [PMID: 29479059 DOI: 10.1038/s41437-018-0064-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Revised: 01/18/2018] [Accepted: 01/18/2018] [Indexed: 11/09/2022] Open
Abstract
Ecological speciation is an important factor in the diversification of plants. The distribution of the woody species Rhododendron indicum, which grows along rivers and is able to withstand water flow when rivers flood (i.e. it is a rheophyte), is disjunct, in contrast to the widespread distribution of its relative, Rhododendron kaempferi. This study aimed to elucidate the phylogenetic relationships between R. indicum and R. kaempferi and the evolutionary processes that gave rise to them. The sequences of three non-coding chloroplast DNA regions (total length 1977 bp) were obtained from 21 populations covering the ranges of the two species. In addition, genome-wide SNPs were genotyped from 20 populations using a genotyping by sequencing method. Leaf morphologies were measured for eight representative populations. Two chloroplast DNA haplotypes, which were detected in R. indicum, were shared between the two species. Genome-wide SNPs identified two lineages in R. indicum and these lineages did not constitute a monophyletic group. Each of these two lineages was related to geographically close populations of R. kaempferi. Leaf morphology, which is a characteristic feature in rheophytes, was not differentiated between the two lineages in R. indicum. The morphological similarity between the two heterogeneous lineages may be a result of parallel evolution from R. kaempferi or of introgressive hybridization between the species due to strong selective pressure imposed by flooding.
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Affiliation(s)
- Watanabe Yoichi
- Graduate School of Horticulture, Chiba University, Matsudo 648, Matsudo, Chiba, 271-8510, Japan.
| | - Izumi Kawamata
- Faculty of Horticulture, Chiba University, Matsudo 648, Matsudo, Chiba, 271-8510, Japan
| | - Yu Matsuki
- Graduate School of Agricultural Science, Tohoku University, Naruko-onsen Yomogida 232-3, Osaki, Miyagi, 989-6711, Japan
| | - Yoshihisa Suyama
- Graduate School of Agricultural Science, Tohoku University, Naruko-onsen Yomogida 232-3, Osaki, Miyagi, 989-6711, Japan
| | - Koichi Uehara
- College of Liberal Arts and Sciences, Chiba University, Yayoi-cho 1-33, Inage-ku, Chiba, 263-8522, Japan
| | - Motomi Ito
- Graduate School of Arts and Sciences, The University of Tokyo, Komaba 3-8-1, Meguro-ku, Tokyo, 153-8902, Japan
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13
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Phylogeographic testing of alternative histories of single-origin versus parallel evolution of early flowering serpentine populations of Picris hieracioides L. (Asteraceae) in Japan. Ecol Res 2017. [DOI: 10.1007/s11284-017-1536-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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14
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Pérez-Pereira N, Quesada H, Caballero A. Can parallel ecological speciation be detected with phylogenetic analyses? Mol Phylogenet Evol 2017; 116:149-156. [PMID: 28870507 DOI: 10.1016/j.ympev.2017.08.019] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Revised: 07/26/2017] [Accepted: 08/31/2017] [Indexed: 11/25/2022]
Abstract
Distinguishing parallel divergence from vicariance scenarios is crucial to establish the determinism of natural selection in the formation of new species. It has been proposed that phylogenetic methods can be used to disentangle a single origin in allopatry and multiple origins in sympatry for ecological speciation. However, a key issue is to what extent introgression in a patchy environment may complicate the distinction between both origins through the analysis of variation at neutral markers. While divergence at environmentally-based selected loci retains the initial correlation with ecological variables, such association may be lost at neutral loci unlinked to any selected locus. Thus, neutral divergence might reflect in the long-term the molecular fingerprint of isolation by distance regardless of the model of speciation considered, and a question arises as to whether phylogenetic analyses of neutral markers are able or not to retrieve the signals acquired in the ancestral populations. Here, we use computer simulations to show that the detection of the original signal using a phylogenetic method strongly depends on the migration rates among populations. Recombination accelerates the loss of the initial phylogenetic signal, but this effect is rather small compared with the effect of migration, and only substantial when recombination is very large. For model species with reduced gene flow between distant populations and between populations adapted to different habitats, the phylogenetic approach is able to distinguish a single origin in allopatry from multiple origins in sympatry.
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Affiliation(s)
- Noelia Pérez-Pereira
- Departamento de Bioquímica, Genética e Inmunología, Facultad de Biología, Universidad de Vigo, 36310 Vigo, Pontevedra, Spain
| | - Humberto Quesada
- Departamento de Bioquímica, Genética e Inmunología, Facultad de Biología, Universidad de Vigo, 36310 Vigo, Pontevedra, Spain
| | - Armando Caballero
- Departamento de Bioquímica, Genética e Inmunología, Facultad de Biología, Universidad de Vigo, 36310 Vigo, Pontevedra, Spain.
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15
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RADseq provides evidence for parallel ecotypic divergence in the autotetraploid Cochlearia officinalis in Northern Norway. Sci Rep 2017; 7:5573. [PMID: 28717144 PMCID: PMC5514025 DOI: 10.1038/s41598-017-05794-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 06/02/2017] [Indexed: 11/08/2022] Open
Abstract
Speciation encompasses a continuum over time from freely interbreeding populations to reproductively isolated species. Along this process, ecotypes - the result of local adaptation - may be on the road to new species. We investigated whether three autotetraploid Cochlearia officinalis ecotypes, adapted to different habitats (beach, estuary, spring), are genetically differentiated and result from parallel ecotypic divergence in two distinct geographical regions. We obtained genetic data from thousands of single nucleotide polymorphisms (SNPs) from restriction-site associated DNA sequencing (RADseq) and from six microsatellite markers for 12 populations to assess genetic divergence at ecotypic, geographic and population level. The genetic patterns support differentiation among ecotypes as suggested by morphology and ecology. The data fit a scenario where the ancestral beach ecotype has recurrently and polytopically given rise to the estuary and spring ecotypes. Several ecologically-relevant loci with consistent non-random segregating patterns are identified across the recurrent origins, in particular around genes related to salt stress. Despite being ecologically distinct, the Cochlearia ecotypes still represent an early stage in the process of speciation, as reproductive isolation has not (yet) developed. A sequenced annotated genome is needed to specifically target candidate genes underlying local adaptation.
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16
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Hooker OE, Van Leeuwen TE, Adams CE. The physiological costs of prey switching reinforce foraging specialization. J Anim Ecol 2017; 86:605-614. [DOI: 10.1111/1365-2656.12632] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Accepted: 11/28/2016] [Indexed: 11/28/2022]
Affiliation(s)
- Oliver E. Hooker
- Scottish Centre for Ecology and the Natural Environment IBAHCM University of Glasgow Rowardennan Loch Lomond Glasgow G63 0AW UK
- PR Statistics 3/1, 128 Brunswick Street Glasgow G1 1TF UK
| | - Travis E. Van Leeuwen
- Scottish Centre for Ecology and the Natural Environment IBAHCM University of Glasgow Rowardennan Loch Lomond Glasgow G63 0AW UK
| | - Colin E. Adams
- Scottish Centre for Ecology and the Natural Environment IBAHCM University of Glasgow Rowardennan Loch Lomond Glasgow G63 0AW UK
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17
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Hanson D, Barrett RDH, Hendry AP. Testing for parallel allochronic isolation in lake-stream stickleback. J Evol Biol 2015; 29:47-57. [DOI: 10.1111/jeb.12761] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Revised: 09/02/2015] [Accepted: 09/10/2015] [Indexed: 01/17/2023]
Affiliation(s)
- D. Hanson
- Redpath Museum and Department of Biology; McGill University; Montreal QC Canada
| | - R. D. H. Barrett
- Redpath Museum and Department of Biology; McGill University; Montreal QC Canada
| | - A. P. Hendry
- Redpath Museum and Department of Biology; McGill University; Montreal QC Canada
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18
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Baack E, Melo MC, Rieseberg LH, Ortiz-Barrientos D. The origins of reproductive isolation in plants. THE NEW PHYTOLOGIST 2015; 207:968-84. [PMID: 25944305 DOI: 10.1111/nph.13424] [Citation(s) in RCA: 192] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Accepted: 03/16/2015] [Indexed: 05/23/2023]
Abstract
Reproductive isolation in plants occurs through multiple barriers that restrict gene flow between populations, but their origins remain uncertain. Work in the past decade has shown that postpollination barriers, such as the failure to form hybrid seeds or sterility of hybrid offspring, are often less strong than prepollination barriers. Evidence implicates multiple evolutionary forces in the origins of reproductive barriers, including mutation, stochastic processes and natural selection. Although adaptation to different environments is a common element of reproductive isolation, genomic conflicts also play a role, including female meiotic drive. The genetic basis of some reproductive barriers, particularly flower colour influencing pollinator behaviour, is well understood in some species, but the genetic changes underlying many other barriers, especially pollen-stylar interactions, are largely unknown. Postpollination barriers appear to accumulate at a faster rate in annuals compared with perennials, due in part to chromosomal rearrangements. Chromosomal changes can be important isolating barriers in themselves but may also reduce the recombination of genes contributing to isolation. Important questions for the next decade include identifying the evolutionary forces responsible for chromosomal rearrangements, determining how often prezygotic barriers arise due to selection against hybrids, and establishing the relative importance of genomic conflicts in speciation.
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Affiliation(s)
- Eric Baack
- Department of Biology, Luther College, Decorah, IA, 52101, USA
| | - Maria Clara Melo
- School of Biological Sciences, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Loren H Rieseberg
- Department of Botany, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
- Department of Biology, Indiana University, Bloomington, IN, 47405, USA
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19
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Breitkopf H, Onstein RE, Cafasso D, Schlüter PM, Cozzolino S. Multiple shifts to different pollinators fuelled rapid diversification in sexually deceptive Ophrys orchids. THE NEW PHYTOLOGIST 2015; 207:377-389. [PMID: 25521237 DOI: 10.1111/nph.13219] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Accepted: 10/31/2014] [Indexed: 05/03/2023]
Abstract
Episodes of rapid speciation provide unique insights into evolutionary processes underlying species radiations and patterns of biodiversity. Here we investigated the radiation of sexually deceptive bee orchids (Ophrys). Based on a time-calibrated phylogeny and by means of ancestral character reconstruction and divergence time estimation, we estimated the tempo and mode of this radiation within a state-dependent evolutionary framework. It appears that, in the Pleistocene, the evolution of Ophrys was marked by episodes of rapid diversification coinciding with shifts to different pollinator types: from wasps to Eucera bees to Andrena and other bees. An abrupt increase in net diversification rate was detected in three clades. Among these, two phylogenetically distant lineages switched from Eucera to Andrena and other bees in a parallel fashion and at about the same time in their evolutionary history. Lack of early radiation associated with the evolution of the key innovation of sexual deception suggests that Ophrys diversification was mainly driven by subsequent ecological opportunities provided by the exploitation of novel pollinator groups, encompassing many bee species slightly differing in their sex pheromone communication systems, and by spatiotemporal fluctuations in the pollinator mosaic.
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Affiliation(s)
- Hendrik Breitkopf
- Department of Biology, University of Naples Federico II, Naples, Italy
- Institute of Biochemistry and Biology, Biodiversity Research/Systematic Botany, University of Potsdam, Potsdam, Germany
| | - Renske E Onstein
- Institute of Systematic Botany, University of Zurich, Zurich, Switzerland
| | - Donata Cafasso
- Department of Biology, University of Naples Federico II, Naples, Italy
| | - Philipp M Schlüter
- Institute of Systematic Botany, University of Zurich, Zurich, Switzerland
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20
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Xu S, Schlüter PM. Modeling the two-locus architecture of divergent pollinator adaptation: how variation in SAD paralogs affects fitness and evolutionary divergence in sexually deceptive orchids. Ecol Evol 2015; 5:493-502. [PMID: 25691974 PMCID: PMC4314279 DOI: 10.1002/ece3.1378] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Accepted: 12/01/2014] [Indexed: 01/26/2023] Open
Abstract
Divergent selection by pollinators can bring about strong reproductive isolation via changes at few genes of large effect. This has recently been demonstrated in sexually deceptive orchids, where studies (1) quantified the strength of reproductive isolation in the field; (2) identified genes that appear to be causal for reproductive isolation; and (3) demonstrated selection by analysis of natural variation in gene sequence and expression. In a group of closely related Ophrys orchids, specific floral scent components, namely n-alkenes, are the key floral traits that control specific pollinator attraction by chemical mimicry of insect sex pheromones. The genetic basis of species-specific differences in alkene production mainly lies in two biosynthetic genes encoding stearoyl–acyl carrier protein desaturases (SAD) that are associated with floral scent variation and reproductive isolation between closely related species, and evolve under pollinator-mediated selection. However, the implications of this genetic architecture of key floral traits on the evolutionary processes of pollinator adaptation and speciation in this plant group remain unclear. Here, we expand on these recent findings to model scenarios of adaptive evolutionary change at SAD2 and SAD5, their effects on plant fitness (i.e., offspring number), and the dynamics of speciation. Our model suggests that the two-locus architecture of reproductive isolation allows for rapid sympatric speciation by pollinator shift; however, the likelihood of such pollinator-mediated speciation is asymmetric between the two orchid species O. sphegodes and O. exaltata due to different fitness effects of their predominant SAD2 and SAD5 alleles. Our study not only provides insight into pollinator adaptation and speciation mechanisms of sexually deceptive orchids but also demonstrates the power of applying a modeling approach to the study of pollinator-driven ecological speciation.
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Affiliation(s)
- Shuqing Xu
- Department of Molecular Ecology, Max Planck Institute for Chemical Ecology Hans-Knöll-Straße 8, D-07745, Jena, Germany
| | - Philipp M Schlüter
- Institute of Systematic Botany, University of Zurich Zollikerstrasse 107, CH-8008, Zürich, Switzerland
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21
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Incipient radiation within the dominant Hawaiian tree Metrosideros polymorpha. Heredity (Edinb) 2014; 113:334-42. [PMID: 24824285 DOI: 10.1038/hdy.2014.47] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Revised: 03/23/2014] [Accepted: 04/01/2014] [Indexed: 01/19/2023] Open
Abstract
Although trees comprise a primary component of terrestrial species richness, the drivers and temporal scale of divergence in trees remain poorly understood. We examined the landscape-dominant tree, Metrosideros polymorpha, for variation at nine microsatellite loci across 23 populations on young Hawai'i Island, sampling each of the island's five varieties throughout its full geographic range. For four varieties, principal coordinate analysis revealed strong clustering of populations by variety across the 10 430 km(2) island, indicating partitioning of the species into multiple evolutionarily significant units. The single island-endemic form, riparian var. newellii, showed especially strong differentiation from other varieties despite occurring in sympatry with other varieties and likely evolved from a bog form on the oldest volcano, Kohala, within the past 500 000 years. Along with comparable riparian forms on other Pacific Islands, var. newellii appears to represent parallel incipient ecological speciation within Metrosideros. Greater genetic distance among the more common varieties on the oldest volcano and an inverse relationship between allelic diversity and substrate age appear consistent with colonization of Hawai'i Island by older, partially diverged varieties followed by increased hybridization among varieties on younger volcanoes. This study demonstrates that broad population-level sampling is required to uncover patterns of diversification within a ubiquitous and long-lived tree species. Hawaiian Metrosideros appears to be a case of incipient radiation in trees and thus should be useful for studies of divergence and the evolution of reproductive isolating barriers at the early stages of speciation.
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22
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Butlin RK, Saura M, Charrier G, Jackson B, André C, Caballero A, Coyne JA, Galindo J, Grahame JW, Hollander J, Kemppainen P, Martínez-Fernández M, Panova M, Quesada H, Johannesson K, Rolán-Alvarez E. Parallel evolution of local adaptation and reproductive isolation in the face of gene flow. Evolution 2013; 68:935-49. [PMID: 24299519 PMCID: PMC4261988 DOI: 10.1111/evo.12329] [Citation(s) in RCA: 122] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Accepted: 11/06/2013] [Indexed: 01/28/2023]
Abstract
Parallel evolution of similar phenotypes provides strong evidence for the operation of natural selection. Where these phenotypes contribute to reproductive isolation, they further support a role for divergent, habitat-associated selection in speciation. However, the observation of pairs of divergent ecotypes currently occupying contrasting habitats in distinct geographical regions is not sufficient to infer parallel origins. Here we show striking parallel phenotypic divergence between populations of the rocky-shore gastropod, Littorina saxatilis, occupying contrasting habitats exposed to either wave action or crab predation. This divergence is associated with barriers to gene exchange but, nevertheless, genetic variation is more strongly structured by geography than by ecotype. Using approximate Bayesian analysis of sequence data and amplified fragment length polymorphism markers, we show that the ecotypes are likely to have arisen in the face of continuous gene flow and that the demographic separation of ecotypes has occurred in parallel at both regional and local scales. Parameter estimates suggest a long delay between colonization of a locality and ecotype formation, perhaps because the postglacial spread of crab populations was slower than the spread of snails. Adaptive differentiation may not be fully genetically independent despite being demographically parallel. These results provide new insight into a major model of ecologically driven speciation.
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Affiliation(s)
- Roger K Butlin
- Animal and Plant Sciences, The University of Sheffield, Sheffield S10 2TN, United Kingdom; Biological and Environmental Sciences-Tjärnö, University of Gothenburg, SE-452 96, Strömstad, Sweden.
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23
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Pereyra RT, Huenchuñir C, Johansson D, Forslund H, Kautsky L, Jonsson PR, Johannesson K. Parallel speciation or long-distance dispersal? Lessons from seaweeds (Fucus) in the Baltic Sea. J Evol Biol 2013; 26:1727-37. [PMID: 23859364 DOI: 10.1111/jeb.12170] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Revised: 03/04/2013] [Accepted: 03/28/2013] [Indexed: 11/30/2022]
Abstract
Parallel evolution has been invoked as a forceful mechanism of ecotype and species formation in many animal taxa. However, parallelism may be difficult to separate from recently monophyletically diverged species that are likely to show complex genetic relationships as a result of considerable shared ancestral variation and secondary hybridization in local areas. Thus, species' degrees of reproductive isolation, barriers to dispersal and, in particular, limited capacities for long-distance dispersal will affect demographical structures underlying mechanisms of divergent evolution. Here, we used nine microsatellite DNA markers to study intra- and interspecific genetic diversity of two recently diverged species of brown macroalgae, Fucus radicans (L. Bergström & L. Kautsky) and F. vesiculosus (Linnaeus), in the Baltic Sea. We further performed biophysical modelling to identify likely connectivity patterns influencing the species' genetic structures. For each species, we found intraspecific contrasting patterns of clonality incidence and population structure. In addition, strong genetic differentiation between the two species within each locality supported the existence of two distinct evolutionary lineages (FST = 0.15-0.41). However, overall genetic clustering analyses across both species' populations revealed that all populations from one region (Estonia) were more genetically similar to each other than to their own taxon from the other two regions (Sweden and Finland). Our data support a hypothesis of parallel speciation. Alternatively, Estonia may be the ancestral source of both species, but is presently isolated by oceanographic barriers to dispersal. Thus, a limited gene flow in combination with genetic drift could have shaped the seemingly parallel structure.
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Affiliation(s)
- R T Pereyra
- Department of Biological and Environmental Sciences - Tjärnö, University of Gothenburg, Strömstad, Sweden.
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24
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Andrew RL, Kane NC, Baute GJ, Grassa CJ, Rieseberg LH. Recent nonhybrid origin of sunflower ecotypes in a novel habitat. Mol Ecol 2012; 22:799-813. [DOI: 10.1111/mec.12038] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Revised: 07/27/2012] [Accepted: 07/30/2012] [Indexed: 02/04/2023]
Affiliation(s)
- Rose L. Andrew
- Department of Botany; University of British Columbia; 3529-6270 University Blvd; Vancouver; BC; Canada; V6T 1Z4
| | - Nolan C. Kane
- Department of Botany; University of British Columbia; 3529-6270 University Blvd; Vancouver; BC; Canada; V6T 1Z4
| | - Greg J. Baute
- Department of Botany; University of British Columbia; 3529-6270 University Blvd; Vancouver; BC; Canada; V6T 1Z4
| | - Christopher J. Grassa
- Department of Botany; University of British Columbia; 3529-6270 University Blvd; Vancouver; BC; Canada; V6T 1Z4
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25
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Thorpe RS, Surget-Groba Y, Johansson H. Quantitative traits and mode of speciation in Martinique anoles. Mol Ecol 2012; 21:5299-308. [PMID: 23043323 DOI: 10.1111/j.1365-294x.2012.05737.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Revised: 06/21/2012] [Accepted: 06/28/2012] [Indexed: 01/08/2023]
Abstract
We investigate extensive quantitative trait variation (dewlap hue, colour pattern, dorsum hue, body proportions and scalation) in the Martinique anole across eight transects representing nascent parapatric ecological speciation, nascent allopatric speciation and allopatric divergence without sufficient genetic structure to suggest speciation. Quantitative trait divergence can be extremely large between adjacent sets of populations, but with one exception that this is associated with difference in habitat rather than past allopatry. Nascent ecological speciation shows the greatest level of quantitative trait divergence across all character sets including those implicated in natural, as well as sexual selection. The sole example of nascent allopatric speciation is associated with fairly strong quantitative trait divergence among most character sets, but not the set most implicated in natural (rather than sexual) selection. The role of sexual selection in ecological speciation is discussed, both in terms of female choice with assortative mating and male-male competition with condition-dependant sexual signals.
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Affiliation(s)
- Roger S Thorpe
- School of Biological Sciences, Bangor University, Bangor, LL57 2UW, UK.
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26
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The Role of Parasitism in Adaptive Radiations—When Might Parasites Promote and When Might They Constrain Ecological Speciation? INTERNATIONAL JOURNAL OF ECOLOGY 2012. [DOI: 10.1155/2012/280169] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Research on speciation and adaptive radiation has flourished during the past decades, yet factors underlying initiation of reproductive isolation often remain unknown. Parasites represent important selective agents and have received renewed attention in speciation research. We review the literature on parasite-mediated divergent selection in context of ecological speciation and present empirical evidence for three nonexclusive mechanisms by which parasites might facilitate speciation: reduced viability or fecundity of immigrants and hybrids, assortative mating as a pleiotropic by-product of host adaptation, and ecologically-based sexual selection. We emphasise the lack of research on speciation continuums, which is why no study has yet made a convincing case for parasite driven divergent evolution to initiate the emergence of reproductive isolation. We also point interest towards selection imposed by single versus multiple parasite species, conceptually linking this to strength and multifariousness of selection. Moreover, we discuss how parasites, by manipulating behaviour or impairing sensory abilities of hosts, may change the form of selection that underlies speciation. We conclude that future studies should consider host populations at variable stages of the speciation process, and explore recurrent patterns of parasitism and resistance that could pinpoint the role of parasites in imposing the divergent selection that initiates ecological speciation.
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