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Wong ELY, Filatov DA. The role of recombination landscape in species hybridisation and speciation. FRONTIERS IN PLANT SCIENCE 2023; 14:1223148. [PMID: 37484464 PMCID: PMC10361763 DOI: 10.3389/fpls.2023.1223148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 06/13/2023] [Indexed: 07/25/2023]
Abstract
It is now well recognised that closely related species can hybridize and exchange genetic material, which may promote or oppose adaptation and speciation. In some cases, interspecific hybridisation is very common, making it surprising that species identity is preserved despite active gene exchange. The genomes of most eukaryotic species are highly heterogeneous with regard to gene density, abundance of repetitive DNA, chromatin compactisation etc, which can make certain genomic regions more prone or more resistant to introgression of genetic material from other species. Heterogeneity in local recombination rate underpins many of the observed patterns across the genome (e.g. actively recombining regions are typically gene rich and depleted for repetitive DNA) and it can strongly affect the permeability of genomic regions to interspecific introgression. The larger the region lacking recombination, the higher the chance for the presence of species incompatibility gene(s) in that region, making the entire non- or rarely recombining block impermeable to interspecific introgression. Large plant genomes tend to have highly heterogeneous recombination landscape, with recombination frequently occurring at the ends of the chromosomes and central regions lacking recombination. In this paper we review the relationship between recombination and introgression in plants and argue that large rarely recombining regions likely play a major role in preserving species identity in actively hybridising plant species.
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Affiliation(s)
- Edgar L. Y. Wong
- Department of Biology, University of Oxford, Oxford, United Kingdom
- Senckenberg Biodiversity and Climate Research Centre, Frankfurt am Main, Germany
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2
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Caeiro-Dias G, Brelsford A, Meneses-Ribeiro M, Crochet PA, Pinho C. Hybridization in late stages of speciation: Strong but incomplete genome-wide reproductive isolation and 'large Z-effect' in a moving hybrid zone. Mol Ecol 2023. [PMID: 37316984 DOI: 10.1111/mec.17035] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 04/27/2023] [Accepted: 05/12/2023] [Indexed: 06/16/2023]
Abstract
In organisms reproducing sexually, speciation occurs when increasing divergence results in pre- or post-zygotic reproductive isolation between lineages. Studies focusing on reproductive isolation origin in early stages of speciation are common and many rely on genomic scans to infer introgression providing limited information on the genomic architecture of reproductive isolation long-term maintenance. This study analyses a natural hybrid zone between two species in a late stage of speciation. We used ddRADseq genotyping in the contact between Podarcis bocagei and P. carbonelli to examine admixture extent, analyse hybrid zone stability and assess genome-wide variation in selection against introgression. We confirmed strong but incomplete reproductive isolation in a bimodal hybrid zone. New findings revealed population genetic structure within P. carbonelli in the contact zone; geographical and genomic clines analysis suggested strong selection against gene flow, but a relatively small proportion of the loci can introgress, mostly within the narrow contact zone. However, geographical clines revealed that a few introgressed loci show signs of potential positive selection, particularly into P. bocagei. Geographical clines also detected a signal of hybrid zone movement towards P. bocagei distribution. Genomic cline analysis revealed heterogeneous patterns of introgression among loci within the syntopy zone, but the majority maintain a strong association with the genomic background of origin. However, incongruences between both cline approaches were found, potentially driven by confounding effects on genomic clines. Last, an important role of the Z chromosome in reproductive isolation is suggested. Importantly, overall patterns of restricted introgression seem to result from numerous strong intrinsic barriers across the genome.
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Affiliation(s)
- Guilherme Caeiro-Dias
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO Laboratório Associado, Universidade do Porto, Vairão, Portugal
- Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Porto, Portugal
- CEFE, CNRS, Univ Montpellier, EPHE, IRD, Montpellier, France
| | - Alan Brelsford
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
- Biology Department, University of California Riverside, Riverside, California, USA
| | - Mariana Meneses-Ribeiro
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO Laboratório Associado, Universidade do Porto, Vairão, Portugal
- Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Porto, Portugal
- BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Vairão, Portugal
| | - Pierre-André Crochet
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
| | - Catarina Pinho
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO Laboratório Associado, Universidade do Porto, Vairão, Portugal
- BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Vairão, Portugal
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3
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Id-Lahoucine S, Casellas J, Miglior F, Schenkel FS, Cánovas A. Parent-offspring genotyped trios unravelling genomic regions with gametic and genotypic epistatic transmission bias on the cattle genome. Front Genet 2023; 14:1132796. [PMID: 37091801 PMCID: PMC10117652 DOI: 10.3389/fgene.2023.1132796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Accepted: 03/20/2023] [Indexed: 04/08/2023] Open
Abstract
Several biological mechanisms affecting the sperm and ova fertility and viability at developmental stages of the reproductive cycle resulted in observable transmission ratio distortion (i.e., deviation from Mendelian expectations). Gene-by-gene interactions (or epistasis) could also potentially cause specific transmission ratio distortion patterns at different loci as unfavorable allelic combinations are under-represented, exhibiting deviation from Mendelian proportions. Here, we aimed to detect pairs of loci with epistatic transmission ratio distortion using 283,817 parent-offspring genotyped trios (sire-dam-offspring) of Holstein cattle. Allelic and genotypic parameterization for epistatic transmission ratio distortion were developed and implemented to scan the whole genome. Different epistatic transmission ratio distortion patterns were observed. Using genotypic models, 7, 19 and 6 pairs of genomic regions were found with decisive evidence with additive-by-additive, additive-by-dominance/dominance-by-additive and dominance-by-dominance effects, respectively. Using the allelic transmission ratio distortion model, more insight was gained in understanding the penetrance of single-locus distortions, revealing 17 pairs of SNPs. Scanning for the depletion of individuals carrying pairs of homozygous genotypes for unlinked loci, revealed 56 pairs of SNPs with recessive epistatic transmission ratio distortion patterns. The maximum number of expected homozygous offspring, with none of them observed, was 23. Finally, in this study, we identified candidate genomic regions harboring epistatic interactions with potential biological implications in economically important traits, such as reproduction.
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Affiliation(s)
- Samir Id-Lahoucine
- Centre for Genetic Improvement of Livestock, Department of Animal Biosciences, University of Guelph, Guelph, ON, Canada
| | - Joaquim Casellas
- Departament de Ciència Animal i dels Aliments, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Filippo Miglior
- Centre for Genetic Improvement of Livestock, Department of Animal Biosciences, University of Guelph, Guelph, ON, Canada
| | - Flavio S. Schenkel
- Centre for Genetic Improvement of Livestock, Department of Animal Biosciences, University of Guelph, Guelph, ON, Canada
| | - Angela Cánovas
- Centre for Genetic Improvement of Livestock, Department of Animal Biosciences, University of Guelph, Guelph, ON, Canada
- *Correspondence: Angela Cánovas,
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4
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Wong ELY, Nevado B, Hiscock SJ, Filatov DA. Rapid evolution of hybrid breakdown following recent divergence with gene flow in Senecio species on Mount Etna, Sicily. Heredity (Edinb) 2023; 130:40-52. [PMID: 36494489 PMCID: PMC9814926 DOI: 10.1038/s41437-022-00576-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Revised: 11/07/2022] [Accepted: 11/08/2022] [Indexed: 12/13/2022] Open
Abstract
How do nascent species evolve reproductive isolation during speciation with on-going gene flow? How do hybrid lineages become stabilised hybrid species? While commonly used genomic approaches provide an indirect way to identify species incompatibility factors, synthetic hybrids generated from interspecific crosses allow direct pinpointing of phenotypic traits involved in incompatibilities and the traits that are potentially adaptive in hybrid species. Here we report the analysis of phenotypic variation and hybrid breakdown in crosses between closely-related Senecio aethnensis and S. chrysanthemifolius, and their homoploid hybrid species, S. squalidus. The two former species represent a likely case of recent (<200 ky) speciation with gene flow driven by adaptation to contrasting conditions of high- and low-elevations on Mount Etna, Sicily. As these species form viable and fertile hybrids, it remains unclear whether they have started to evolve reproductive incompatibility. Our analysis represents the first study of phenotypic variation and hybrid breakdown involving multiple Senecio hybrid families. It revealed wide range of variation in multiple traits, including the traits previously unrecorded in synthetic hybrids. Leaf shape, highly distinct between S. aethnensis and S. chrysanthemifolius, was extremely variable in F2 hybrids, but more consistent in S. squalidus. Our study demonstrates that interspecific incompatibilities can evolve rapidly despite on-going gene flow between the species. Further work is necessary to understand the genetic bases of these incompatibilities and their role in speciation with gene flow.
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Affiliation(s)
- Edgar L. Y. Wong
- grid.4991.50000 0004 1936 8948Department of Biology, University of Oxford, Oxford, UK ,grid.507705.0Senckenberg Biodiversity and Climate Research Centre, Frankfurt am Main, Germany
| | - Bruno Nevado
- grid.4991.50000 0004 1936 8948Department of Biology, University of Oxford, Oxford, UK ,grid.9983.b0000 0001 2181 4263Centre for Ecology, Evolution and Environmental Changes, University of Lisbon, Lisbon, Portugal
| | - Simon J. Hiscock
- grid.4991.50000 0004 1936 8948Department of Biology, University of Oxford, Oxford, UK ,Oxford Botanic Garden and Arboretum, Oxford, UK
| | - Dmitry A. Filatov
- grid.4991.50000 0004 1936 8948Department of Biology, University of Oxford, Oxford, UK
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5
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Wang D, Xu X, Zhang H, Xi Z, Abbott RJ, Fu J, Liu JQ. Abiotic niche divergence of hybrid species from their progenitors. Am Nat 2022; 200:634-645. [DOI: 10.1086/721372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Hörandl E. Novel Approaches for Species Concepts and Delimitation in Polyploids and Hybrids. PLANTS (BASEL, SWITZERLAND) 2022; 11:plants11020204. [PMID: 35050093 PMCID: PMC8781807 DOI: 10.3390/plants11020204] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 01/07/2022] [Accepted: 01/10/2022] [Indexed: 05/08/2023]
Abstract
Hybridization and polyploidization are important processes for plant evolution. However, classification of hybrid or polyploid species has been notoriously difficult because of the complexity of processes and different evolutionary scenarios that do not fit with classical species concepts. Polyploid complexes are formed via combinations of allopolyploidy, autopolyploidy and homoploid hybridization with persisting sexual reproduction, resulting in many discrete lineages that have been classified as species. Polyploid complexes with facultative apomixis result in complicated net-work like clusters, or rarely in agamospecies. Various case studies illustrate the problems that apply to traditional species concepts to hybrids and polyploids. Conceptual progress can be made if lineage formation is accepted as an inevitable consequence of meiotic sex, which is established already in the first eukaryotes as a DNA restoration tool. The turnaround of the viewpoint that sex forms species as lineages helps to overcome traditional thinking of species as "units". Lineage formation and self-sustainability is the prerequisite for speciation and can also be applied to hybrids and polyploids. Species delimitation is aided by the improved recognition of lineages via various novel -omics methods, by understanding meiosis functions, and by recognizing functional phenotypes by considering morphological-physiological-ecological adaptations.
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Affiliation(s)
- Elvira Hörandl
- Department of Systematics, Biodiversity and Evolution of Plants (with Herbarium), University of Goettingen, 37073 Göttingen, Germany
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7
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Wong ELY, Hiscock SJ, Filatov DA. The Role of Interspecific Hybridisation in Adaptation and Speciation: Insights From Studies in Senecio. FRONTIERS IN PLANT SCIENCE 2022; 13:907363. [PMID: 35812981 PMCID: PMC9260247 DOI: 10.3389/fpls.2022.907363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Accepted: 06/03/2022] [Indexed: 05/08/2023]
Abstract
Hybridisation is well documented in many species, especially plants. Although hybrid populations might be short-lived and do not evolve into new lineages, hybridisaiton could lead to evolutionary novelty, promoting adaptation and speciation. The genus Senecio (Asteraceae) has been actively used to unravel the role of hybridisation in adaptation and speciation. In this article, we first briefly describe the process of hybridisation and the state of hybridisation research over the years. We then discuss various roles of hybridisation in plant adaptation and speciation illustrated with examples from different Senecio species, but also mention other groups of organisms whenever necessary. In particular, we focus on the genomic and transcriptomic consequences of hybridisation, as well as the ecological and physiological aspects from the hybrids' point of view. Overall, this article aims to showcase the roles of hybridisation in speciation and adaptation, and the research potential of Senecio, which is part of the ecologically and economically important family, Asteraceae.
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Affiliation(s)
- Edgar L. Y. Wong
- Department of Plant Sciences, University of Oxford, Oxford, United Kingdom
- *Correspondence: Edgar L. Y. Wong,
| | - Simon J. Hiscock
- Department of Plant Sciences, University of Oxford, Oxford, United Kingdom
- Oxford Botanic Garden and Arboretum, Oxford, United Kingdom
| | - Dmitry A. Filatov
- Department of Plant Sciences, University of Oxford, Oxford, United Kingdom
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8
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Xia F, Ouyang Y. Recurrent breakdown and rebalance of segregation distortion in the genomes: battle for the transmission advantage. ABIOTECH 2020; 1:246-254. [PMID: 36304131 PMCID: PMC9590546 DOI: 10.1007/s42994-020-00023-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Accepted: 05/28/2020] [Indexed: 01/25/2023]
Abstract
Mendel's laws state that each of the two alleles would segregate during gamete formation and show the same transmission ratio in the next generation. However, an unexpected biased allele transmission was first detected in Drosophila a century ago, and was subsequently observed in other animals, plants, and microorganisms. Such segregation distortion (SD) shows substantial effects in population structure and fitness of the progenies, which would ultimately lead to reproductive isolation and speciation. Here, we trace the early investigations on the violation of Mendelian genetic principle, which appears as a wide-existence phenomenon rather than a case of exception. The occurence of SD in the whole genome was observed in a number of plant species at the single- and multi-locus level. Biased transmission ratio might occur at meiosis stage due to asymmetric movement of the chromosome; transmission ratio advantage is also caused by interaction and battle between the alleles from respective genomes at the genetic and molecular level. The origin of a SD system is likely to be determined by coevolution of the killer and protector via recurrent breakdown or rebalance loop. These updated understandings also promote genetic improvement of hybrid crops.
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Affiliation(s)
- Fan Xia
- National Key Laboratory of Crop Genetic Improvement and National Centre of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan, 430070 China
| | - Yidan Ouyang
- National Key Laboratory of Crop Genetic Improvement and National Centre of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan, 430070 China
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9
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Nevado B, Harris SA, Beaumont MA, Hiscock SJ. Rapid homoploid hybrid speciation in British gardens: The origin of Oxford ragwort (
Senecio squalidus
). Mol Ecol 2020; 29:4221-4233. [DOI: 10.1111/mec.15630] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 08/21/2020] [Accepted: 08/26/2020] [Indexed: 01/17/2023]
Affiliation(s)
- Bruno Nevado
- Department of Plant Sciences University of Oxford Oxford UK
| | | | | | - Simon J. Hiscock
- Department of Plant Sciences University of Oxford Oxford UK
- Oxford Botanic Garden and Arboretum Oxford UK
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10
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Walter GM, Abbott RJ, Brennan AC, Bridle JR, Chapman M, Clark J, Filatov D, Nevado B, Ortiz-Barrientos D, Hiscock SJ. Senecio as a model system for integrating studies of genotype, phenotype and fitness. THE NEW PHYTOLOGIST 2020; 226:326-344. [PMID: 31951018 DOI: 10.1111/nph.16434] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Accepted: 12/17/2019] [Indexed: 05/24/2023]
Abstract
Two major developments have made it possible to use examples of ecological radiations as model systems to understand evolution and ecology. First, the integration of quantitative genetics with ecological experiments allows detailed connections to be made between genotype, phenotype, and fitness in the field. Second, dramatic advances in molecular genetics have created new possibilities for integrating field and laboratory experiments with detailed genetic sequencing. Combining these approaches allows evolutionary biologists to better study the interplay between genotype, phenotype, and fitness to explore a wide range of evolutionary processes. Here, we present the genus Senecio (Asteraceae) as an excellent system to integrate these developments, and to address fundamental questions in ecology and evolution. Senecio is one of the largest and most phenotypically diverse genera of flowering plants, containing species ranging from woody perennials to herbaceous annuals. These Senecio species exhibit many growth habits, life histories, and morphologies, and they occupy a multitude of environments. Common within the genus are species that have hybridized naturally, undergone polyploidization, and colonized diverse environments, often through rapid phenotypic divergence and adaptive radiation. These diverse experimental attributes make Senecio an attractive model system in which to address a broad range of questions in evolution and ecology.
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Affiliation(s)
- Greg M Walter
- School of Biological Sciences, University of Bristol, Bristol, BS8 1TQ, UK
| | - Richard J Abbott
- School of Biology, University of St Andrews, St Andrews, Fife, KY16 9TH, UK
| | - Adrian C Brennan
- School of Biological and Biomedical Sciences, University of Durham, Durham, DH1 3LE, UK
| | - Jon R Bridle
- School of Biological Sciences, University of Bristol, Bristol, BS8 1TQ, UK
| | - Mark Chapman
- School of Biological Sciences, University of Southampton, Southampton, SO17 1BJ, UK
| | - James Clark
- Department of Plant Sciences, University of Oxford, Oxford, OX1 3RB, UK
| | - Dmitry Filatov
- Department of Plant Sciences, University of Oxford, Oxford, OX1 3RB, UK
| | - Bruno Nevado
- Department of Plant Sciences, University of Oxford, Oxford, OX1 3RB, UK
| | | | - Simon J Hiscock
- Department of Plant Sciences, University of Oxford, Oxford, OX1 3RB, UK
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11
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Wong ELY, Nevado B, Osborne OG, Papadopulos AST, Bridle JR, Hiscock SJ, Filatov DA. Strong divergent selection at multiple loci in two closely related species of ragworts adapted to high and low elevations on Mount Etna. Mol Ecol 2019; 29:394-412. [PMID: 31793091 DOI: 10.1111/mec.15319] [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: 06/11/2019] [Revised: 11/28/2019] [Accepted: 11/28/2019] [Indexed: 12/20/2022]
Abstract
Recently diverged species present particularly informative systems for studying speciation and maintenance of genetic divergence in the face of gene flow. We investigated speciation in two closely related Senecio species, S. aethnensis and S. chrysanthemifolius, which grow at high and low elevations, respectively, on Mount Etna, Sicily and form a hybrid zone at intermediate elevations. We used a newly generated genome-wide single nucleotide polymorphism (SNP) dataset from 192 individuals collected over 18 localities along an elevational gradient to reconstruct the likely history of speciation, identify highly differentiated SNPs, and estimate the strength of divergent selection. We found that speciation in this system involved heterogeneous and bidirectional gene flow along the genome, and species experienced marked population size changes in the past. Furthermore, we identified highly-differentiated SNPs between the species, some of which are located in genes potentially involved in ecological differences between species (such as photosynthesis and UV response). We analysed the shape of these SNPs' allele frequency clines along the elevational gradient. These clines show significantly variable coincidence and concordance, indicative of the presence of multifarious selective forces. Selection against hybrids is estimated to be very strong (0.16-0.78) and one of the highest reported in literature. The combination of strong cumulative selection across the genome and previously identified intrinsic incompatibilities probably work together to maintain the genetic and phenotypic differentiation between these species - pointing to the importance of considering both intrinsic and extrinsic factors when studying divergence and speciation.
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Affiliation(s)
- Edgar L Y Wong
- Department of Plant Sciences, University of Oxford, Oxford, UK
| | - Bruno Nevado
- Department of Plant Sciences, University of Oxford, Oxford, UK
| | - Owen G Osborne
- Department of Plant Sciences, University of Oxford, Oxford, UK
| | | | - Jon R Bridle
- School of Biological Sciences, University of Bristol, Bristol, UK
| | - Simon J Hiscock
- Department of Plant Sciences, University of Oxford, Oxford, UK
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12
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Volis S, Zhang YH, Deng T, Dorman M, Blecher M, Abbott RJ. Divergence and reproductive isolation between two closely related allopatric Iris species. Biol J Linn Soc Lond 2019. [DOI: 10.1093/biolinnean/blz014] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Sergei Volis
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
| | - Yong-Hong Zhang
- Life Science Department, Yunnan Normal University, Kunming, China
| | - Tao Deng
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
| | - Michael Dorman
- Geography Department, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Michael Blecher
- En Gedi Nature Reserve, Israel Nature and Parks Authority, Dead Sea, Israel
| | - Richard J Abbott
- School of Biology, Harold Mitchell Building, University of St Andrews, St Andrews, Fife, UK
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13
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Delame M, Prado E, Blanc S, Robert-Siegwald G, Schneider C, Mestre P, Rustenholz C, Merdinoglu D. Introgression reshapes recombination distribution in grapevine interspecific hybrids. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2019; 132:1073-1087. [PMID: 30535509 DOI: 10.1007/s00122-018-3260-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 12/03/2018] [Indexed: 05/25/2023]
Abstract
In grapevine interspecific hybrids, meiotic recombination is suppressed in homeologous regions and enhanced in homologous regions of recombined chromosomes, whereas crossover rate remains unchanged when chromosome pairs are entirely homeologous. Vitis rotundifolia, an American species related to the cultivated European grapevine Vitis vinifera, has a high level of resistance to several grapevine major diseases and is consequently a valuable resource for grape breeding. However, crosses between both species most often lead to very few poorly fertile hybrids. In this context, identifying genetic and genomic features that make cross-breeding between both species difficult is essential. To this end, three mapping populations were generated by pseudo-backcrosses using V. rotundifolia as the donor parent and several V. vinifera cultivars as the recurrent parents. Genotyping-by-sequencing was used to establish high-density genetic linkage maps and to determine the genetic composition of the chromosomes of each individual. A good collinearity of the SNP positions was observed between parental maps, confirming the synteny between both species, except on lower arm of chromosome 7. Interestingly, recombination rate in V. rotundifolia × V. vinifera interspecific hybrids depends on the length of the introgressed region. It is similar to grapevine for chromosome pairs entirely homeologous. Conversely, for chromosome pairs partly homeologous, recombination is suppressed in the homeologous regions, whereas it is enhanced in the homologous ones. This balance leads to the conservation of the total genetic length of each chromosome between V. vinifera and hybrid maps, whatever the backcross level and the proportion of homeologous region. Altogether, these results provide new insight to optimize the use of V. rotundifolia in grape breeding and, more generally, to improve the introgression of gene of interest from wild species related to crops.
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Affiliation(s)
- Marion Delame
- SVQV UMR-A 1131, INRA, Université de Strasbourg, 68000, Colmar, France
- Direction des Formations Doctorales, AgroParisTech, 19 avenue du Maine, 75015, Paris, France
| | - Emilce Prado
- SVQV UMR-A 1131, INRA, Université de Strasbourg, 68000, Colmar, France
| | - Sophie Blanc
- SVQV UMR-A 1131, INRA, Université de Strasbourg, 68000, Colmar, France
| | | | | | - Pere Mestre
- SVQV UMR-A 1131, INRA, Université de Strasbourg, 68000, Colmar, France
| | | | - Didier Merdinoglu
- SVQV UMR-A 1131, INRA, Université de Strasbourg, 68000, Colmar, France.
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14
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Brennan AC, Hiscock SJ, Abbott RJ. Completing the hybridization triangle: the inheritance of genetic incompatibilities during homoploid hybrid speciation in ragworts ( Senecio). AOB PLANTS 2019; 11:ply078. [PMID: 30740200 PMCID: PMC6360072 DOI: 10.1093/aobpla/ply078] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 01/04/2019] [Indexed: 05/24/2023]
Abstract
A new homoploid hybrid lineage needs to establish a degree of reproductive isolation from its parent species if it is to persist as an independent entity, but the role hybridization plays in this process is known in only a handful of cases. The homoploid hybrid ragwort species, Senecio squalidus (Oxford ragwort), originated following the introduction of hybrid plants to the UK approximately 320 years ago. The source of the hybrid plants was from a naturally occurring hybrid zone between S. aethnensis and S. chrysanthemifolius on Mount Etna, Sicily. Previous studies of the parent species found evidence for multiple incompatibility loci causing transmission ratio distortion of genetic markers in their hybrid progeny. This study closes the hybridization triangle by reporting a genetic mapping analysis of the remaining two paired cross combinations between S. squalidus and its parents. Genetic maps produced from F2 mapping families were generally collinear but with half of the linkage groups showing evidence of genomic reorganization between genetic maps. The new maps produced from crosses between S. squalidus and each parent showed multiple incompatibility loci distributed across the genome, some of which co-locate with previously reported incompatibility loci between the parents. These findings suggest that this young homoploid hybrid species has inherited a unique combination of genomic rearrangements and incompatibilities from its parents that contribute to its reproductive isolation.
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Affiliation(s)
- Adrian C Brennan
- Department of Biosciences, University of Durham, South Road, Durham, UK
- School of Biology, University of St Andrews, St Andrews, Fife, UK
| | - Simon J Hiscock
- Department of Plant Sciences, University of Oxford, Oxford, UK
| | - Richard J Abbott
- School of Biology, University of St Andrews, St Andrews, Fife, UK
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15
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Giesbers AKJ, den Boer E, Ulen JJWEH, van Kaauwen MPW, Visser RGF, Niks RE, Jeuken MJW. Patterns of Transmission Ratio Distortion in Interspecific Lettuce Hybrids Reveal a Sex-Independent Gametophytic Barrier. Genetics 2019; 211:263-276. [PMID: 30401697 PMCID: PMC6325705 DOI: 10.1534/genetics.118.301566] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 10/30/2018] [Indexed: 11/18/2022] Open
Abstract
Interspecific crosses can result in progeny with reduced vitality or fertility due to genetic incompatibilities between species, a phenomenon known as hybrid incompatibility (HI). HI is often caused by a bias against deleterious allele combinations, which results in transmission ratio distortion (TRD). Here, we determined the genome-wide distribution of HI between wild lettuce, Lactuca saligna, and cultivated lettuce, L. sativa, in a set of backcross inbred lines (BILs) with single introgression segments from L. saligna introgressed into a L. sativa genetic background. Almost all BILs contained an introgression segment in a homozygous state except a few BILs, for which we were able to obtain only a single heterozygous introgression. Their inbred progenies displayed severe TRD with a bias toward the L. sativa allele and complete nontransmission of the homozygous L. saligna introgression, i.e., absolute HI. These HI might be caused by deleterious heterospecific allele combinations at two loci. We used an multilocus segregating interspecific F2 population to identify candidate conspecific loci that can nullify the HI in BILs. Segregation analysis of developed double-introgression progenies showed nullification of three HI and proved that these HI are explained by nuclear pairwise incompatibilities. One of these digenic HI showed 29% reduced seed set and its pattern of TRD pointed to a sex-independent gametophytic barrier. Namely, this HI was caused by complete nontransmission of one heterospecific allele combination at the haploid stage, surprisingly in both male and female gametophytes. Our study shows that two-locus incompatibility systems contribute to reproductive barriers among Lactuca species.
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Affiliation(s)
- Anne K J Giesbers
- Plant Breeding, Wageningen University and Research, 6708 PB Wageningen, The Netherlands
| | - Erik den Boer
- Plant Breeding, Wageningen University and Research, 6708 PB Wageningen, The Netherlands
| | | | | | - Richard G F Visser
- Plant Breeding, Wageningen University and Research, 6708 PB Wageningen, The Netherlands
| | - Rients E Niks
- Plant Breeding, Wageningen University and Research, 6708 PB Wageningen, The Netherlands
| | - Marieke J W Jeuken
- Plant Breeding, Wageningen University and Research, 6708 PB Wageningen, The Netherlands
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16
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The Limits to Parapatric Speciation II: Strengthening a Preexisting Genetic Barrier to Gene Flow in Parapatry. Genetics 2018; 209:241-254. [PMID: 29496748 PMCID: PMC5937195 DOI: 10.1534/genetics.117.300652] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Accepted: 02/27/2018] [Indexed: 11/25/2022] Open
Abstract
By encompassing the whole continuum between allopatric and sympatric scenarios, parapatric speciation includes many potential scenarios for the evolution of new species. Here, we investigate how a genetic barrier to gene flow, that relies on a single postzygotic genetic incompatibility, may further evolve under ongoing migration. We consider a continent island model with three loci involved in pairwise Dobzhansky–Muller incompatibilities (DMIs). Using an analytic approach, we derive the conditions for invasion of a new mutation and its consequences for the strength and stability of the initial genetic barrier. Our results show that the accumulation of genetic incompatibilities in the presence of gene flow is under strong selective constraints. In particular, preexisting incompatibilities do not always facilitate the invasion of further barrier genes. If new mutations do invade, they will often weaken or destroy the barrier rather than strengthening it. We conclude that migration is highly effective at disrupting the so-called “snowball effect”, the accelerated accumulation of DMIs that has been described for allopatric populations en route to reproductive isolation.
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17
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Jordan CY, Lohse K, Turner F, Thomson M, Gharbi K, Ennos RA. Maintaining their genetic distance: Little evidence for introgression between widely hybridizing species of Geum with contrasting mating systems. Mol Ecol 2018; 27:1214-1228. [PMID: 29134729 PMCID: PMC5900869 DOI: 10.1111/mec.14426] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2017] [Revised: 11/02/2017] [Accepted: 11/02/2017] [Indexed: 01/02/2023]
Abstract
Within the plant kingdom, many genera contain sister lineages with contrasting outcrossing and inbreeding mating systems that are known to hybridize. The evolutionary fate of these sister lineages is likely to be influenced by the extent to which they exchange genes. We measured gene flow between outcrossing Geum rivale and selfing Geum urbanum, sister species that hybridize in contemporary populations. We generated and used a draft genome of G. urbanum to develop dd-RAD data scorable in both species. Coalescent analysis of RAD data from allopatric populations indicated that the species diverged 2-3 Mya, and that historical gene flow between them was extremely low (1 migrant every 25 generations). Comparison of genetic divergence between species in sympatry and allopatry, together with an analysis of allele frequencies in potential parental and hybrid populations, provided no evidence of contemporary introgression in sympatric populations. Cluster- and species-specific marker analyses revealed that, apart from four early-generation hybrids, individuals in sympatric populations fell into two genetically distinct groups that corresponded exactly to their morphological species classification with maximum individual admixture estimates of only 1-3%. However, we did observe joint segregation of four putatively introgressed SNPs across two scaffolds in the G. urbanum population that was associated with significant morphological variation, interpreted as tentative evidence for rare, recent interspecific gene flow. Overall, our results indicate that despite the presence of hybrids in contemporary populations, genetic exchange between G. rivale and G. urbanum has been extremely limited throughout their evolutionary history.
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Affiliation(s)
- Crispin Y. Jordan
- Ashworth LaboratoriesInstitute of Evolutionary BiologyUniversity of EdinburghEdinburghUK
| | - Konrad Lohse
- Ashworth LaboratoriesInstitute of Evolutionary BiologyUniversity of EdinburghEdinburghUK
| | | | | | - Karim Gharbi
- Ashworth LaboratoriesEdinburgh GenomicsEdinburghUK
| | - Richard A. Ennos
- Ashworth LaboratoriesInstitute of Evolutionary BiologyUniversity of EdinburghEdinburghUK
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18
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Sung C, Bell KL, Nice CC, Martin NH. Integrating Bayesian genomic cline analyses and association mapping of morphological and ecological traits to dissect reproductive isolation and introgression in a Louisiana Iris hybrid zone. Mol Ecol 2018; 27:959-978. [DOI: 10.1111/mec.14481] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Accepted: 12/14/2017] [Indexed: 01/01/2023]
Affiliation(s)
- Cheng‐Jung Sung
- Population and Conservation Biology Program Department of Biology Texas State University San Marcos TX USA
| | - Katherine L. Bell
- Population and Conservation Biology Program Department of Biology Texas State University San Marcos TX USA
| | - Chris C. Nice
- Population and Conservation Biology Program Department of Biology Texas State University San Marcos TX USA
| | - Noland H. Martin
- Population and Conservation Biology Program Department of Biology Texas State University San Marcos TX USA
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19
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Linkage Map of Lissotriton Newts Provides Insight into the Genetic Basis of Reproductive Isolation. G3-GENES GENOMES GENETICS 2017; 7:2115-2124. [PMID: 28500054 PMCID: PMC5499121 DOI: 10.1534/g3.117.041178] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Linkage maps are widely used to investigate structure, function, and evolution of genomes. In speciation research, maps facilitate the study of the genetic architecture of reproductive isolation by allowing identification of genomic regions underlying reduced fitness of hybrids. Here we present a linkage map for European newts of the Lissotriton vulgaris species complex, constructed using two families of F2 L. montandoni × L. vulgaris hybrids. The map consists of 1146 protein-coding genes on 12 linkage groups, equal to the haploid chromosome number, with a total length of 1484 cM (1.29 cM per marker). It is notably shorter than two other maps available for salamanders, but the differences in map length are consistent with cytogenetic estimates of the number of chiasmata per chromosomal arm. Thus, large salamander genomes do not necessarily translate into long linkage maps, as previously suggested. Consequently, salamanders are an excellent model to study evolutionary consequences of recombination rate variation in taxa with large genomes and a similar number of chromosomes. A complex pattern of transmission ratio distortion (TRD) was detected: TRD occurred mostly in one family, in one breeding season, and was clustered in two genomic segments. This is consistent with environment-dependent mortality of individuals carrying L. montandoni alleles in these two segments and suggests a role of TRD blocks in reproductive isolation. The reported linkage map will empower studies on the genomic architecture of divergence and interactions between the genomes of hybridizing newts.
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20
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Makabe S, Motohashi R, Nakamura I. Growth increase of Arabidopsis by forced expression of rice 45S rRNA gene. PLANT CELL REPORTS 2017; 36:243-254. [PMID: 27864606 DOI: 10.1007/s00299-016-2075-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2016] [Accepted: 11/08/2016] [Indexed: 06/06/2023]
Abstract
Forced expression of rice 45S rRNA gene conferred ca. 2-fold increase of above-ground growth in transgenic Arabidopsis . This growth increase was probably brought by cell proliferation, not by cell enlargement. Recent increase in carbon dioxide emissions is causing global climate change. The use of plant biomass as alternative energy source is one way to reduce these emissions. Therefore, reinforcement of plant biomass production is an urgent key issue to overcome both depletion of fossil energies and emission of carbon dioxide. Here, we created transgenic Arabidopsis with a 2-fold increase in above-ground growth by forced expression of the rice 45S rRNA gene using the maize ubiquitin promoter. Although the size of guard cells and ploidy of leaf-cells were similar between transgenic and control plants, numbers of stomata and pavement cells were much increased in the transgenic leaf. This data suggested that cell number, not cell expansion, was responsible for the growth increase, which might be brought by the forced expression of exogenous and full-length 45S rRNA gene. The expression level of rice 45S rRNA transcripts was very low, possibly triggering unknown machinery to enhance cell proliferation. Although microarray analysis showed enhanced expression of ethylene-responsive transcription factors, these factors might respond to ethylene induced by abiotic/biotic stresses or genomic incompatibility, which might be involved in the expression of species-specific internal transcribed spacer (ITS) sequences within rice 45S rRNA transcripts. Further analysis of the mechanism underlying the growth increase will contribute to understanding the regulation of the cell proliferation and the mechanism of hybrid vigor.
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Affiliation(s)
- So Makabe
- Plant Cell Technology Laboratory, Graduate School of Horticulture, Chiba University, 648 Matsudo, Matsudo, Chiba, 271-8510, Japan
| | - Reiko Motohashi
- Faculty of Agriculture, Shizuoka University, 836 Ohya, Shizuoka, Shizuoka, 422-8529, Japan
| | - Ikuo Nakamura
- Plant Cell Technology Laboratory, Graduate School of Horticulture, Chiba University, 648 Matsudo, Matsudo, Chiba, 271-8510, Japan.
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21
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Brennan AC, Hiscock SJ, Abbott RJ. Genomic architecture of phenotypic divergence between two hybridizing plant species along an elevational gradient. AOB PLANTS 2016; 8:plw022. [PMID: 27083198 PMCID: PMC4887755 DOI: 10.1093/aobpla/plw022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Accepted: 03/19/2016] [Indexed: 05/03/2023]
Abstract
Knowledge of the genetic basis of phenotypic divergence between species and how such divergence is caused and maintained is crucial to an understanding of speciation and the generation of biodiversity. The hybrid zone between Senecio aethnensis and S. chrysanthemifolius on Mount Etna, Sicily, provides a well-studied example of species divergence in response to conditions at different elevations, despite hybridization and gene flow. Here, we investigate the genetic architecture of divergence between these two species using a combination of quantitative trait locus (QTL) mapping and genetic differentiation measures based on genetic marker analysis. A QTL architecture characterized by physical QTL clustering, epistatic interactions between QTLs, and pleiotropy was identified, and is consistent with the presence of divergent QTL complexes resistant to gene flow. A role for divergent selection between species was indicated by significant negative associations between levels of interspecific genetic differentiation at mapped marker gene loci and map distance from QTLs and hybrid incompatibility loci. Within-species selection contributing to interspecific differentiation was evidenced by negative associations between interspecific genetic differentiation and genetic diversity within species. These results show that the two Senecio species, while subject to gene flow, maintain divergent genomic regions consistent with local selection within species and selection against hybrids between species which, in turn, contribute to the maintenance of their distinct phenotypic differences.
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Affiliation(s)
- Adrian C Brennan
- School of Biology, University of St Andrews, Harold Mitchell Building, St Andrews, Fife KY16 9TH, UK Estación Biológica de Doñana (EBD-CSIC), Avenida Américo Vespucio s/n, 41092 Sevilla, Spain Present address: School of Biological and Biomedical Sciences, University of Durham, South Road, Durham DH1 3LE, UK
| | - Simon J Hiscock
- School of Biological Sciences, University of Bristol, Woodland Road, Bristol BS8 1UG, UK
| | - Richard J Abbott
- School of Biology, University of St Andrews, Harold Mitchell Building, St Andrews, Fife KY16 9TH, UK
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22
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Schaefer J, Duvernell D, Campbell DC. Hybridization and introgression in two ecologically dissimilarFundulushybrid zones. Evolution 2016; 70:1051-63. [DOI: 10.1111/evo.12920] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Revised: 03/25/2016] [Accepted: 03/26/2016] [Indexed: 02/01/2023]
Affiliation(s)
- Jacob Schaefer
- Department of Biological Sciences; The University of Southern Mississippi; Hattiesburg Mississippi 39406
| | - David Duvernell
- Department of Biological Sciences; Southern Illinois University Edwardsville; Edwardsville Illinois 62026
| | - Dave Cooper Campbell
- Department of Biological Sciences; The University of Southern Mississippi; Hattiesburg Mississippi 39406
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23
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Filatov DA, Osborne OG, Papadopulos AST. Demographic history of speciation in a Senecio altitudinal hybrid zone on Mt. Etna. Mol Ecol 2016; 25:2467-81. [PMID: 26994342 DOI: 10.1111/mec.13618] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Revised: 02/29/2016] [Accepted: 02/29/2016] [Indexed: 01/16/2023]
Abstract
Hybrid zones typically form as a result of species coming into secondary contact, but can also be established in situ as an ecotonal hybrid zone, a situation which has been reported far less frequently. An altitudinal hybrid zone on Mount Etna between two ragwort species (the low elevation Senecio chrysanthemifolius and high elevation S. aethnensis) could potentially represent either of these possibilities. However, a scenario of secondary contact vs. speciation with gene flow has not been explicitly tested. Here, we test these alternatives and demonstrate that the data do not support secondary contact. Furthermore, we report that the previous analyses of speciation history of these species were based on admixed populations, which has led to inflated estimates of ongoing, interspecific gene flow. Our new analyses, based on 'pure' S. aethnensis and S. chrysanthemifolius populations, reveal gene exchange of less than one effective migrant per generation, a level low enough to allow the species to accumulate neutral, genomewide differences. Overall, our results are consistent with a scenario of speciation with gene flow and a divergence time which coincides with the rise of Mt. Etna to altitudes above 2000 m (~150 KY). Further work to quantify the role of adaptation to contrasting environments of high and low altitudes will be needed to support the scenario of recent ecological speciation in this system.
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Affiliation(s)
- Dmitry A Filatov
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, UK
| | - Owen G Osborne
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, UK
| | - Alexander S T Papadopulos
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, UK.,Royal Botanic Gardens, Kew, Richmond, TW9 3AB, UK
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24
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Osborne OG, Chapman MA, Nevado B, Filatov DA. Maintenance of Species Boundaries Despite Ongoing Gene Flow in Ragworts. Genome Biol Evol 2016; 8:1038-47. [PMID: 26979797 PMCID: PMC4860686 DOI: 10.1093/gbe/evw053] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/07/2016] [Indexed: 12/22/2022] Open
Abstract
The role of hybridization between diversifying species has been the focus of a huge amount of recent evolutionary research. While gene flow can prevent speciation or initiate species collapse, it can also generate new hybrid species. Similarly, while adaptive divergence can be wiped out by gene flow, new adaptive variation can be introduced via introgression. The relative frequency of these outcomes, and indeed the frequency of hybridization and introgression in general are largely unknown. One group of closely-related species with several documented cases of hybridization is the Mediterranean ragwort (genus: Senecio) species-complex. Examples of both polyploid and homoploid hybrid speciation are known in the clade, although their evolutionary relationships and the general frequency of introgressive hybridization among them remain unknown. Using a whole genome gene-space dataset comprising eight Senecio species we fully resolve the phylogeny of these species for the first time despite phylogenetic incongruence across the genome. Using a D-statistic approach, we demonstrate previously unknown cases of introgressive hybridization between multiple pairs of taxa across the species tree. This is an important step in establishing these species as a study system for diversification with gene flow, and suggests that introgressive hybridization may be a widespread and important process in plant evolution.
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Affiliation(s)
- Owen G Osborne
- Department of Plant Sciences, University of Oxford, Oxford, United Kingdom Department of Life Sciences, Imperial College London - Silwood Park Campus, Berkshire, United Kingdom
| | - Mark A Chapman
- Department of Plant Sciences, University of Oxford, Oxford, United Kingdom Department of Life Sciences, Imperial College London - Silwood Park Campus, Berkshire, United Kingdom Centre for Biological Sciences, Faculty of Natural & Environmental Sciences, University of Southampton, Southampton, United Kingdom
| | - Bruno Nevado
- Department of Plant Sciences, University of Oxford, Oxford, United Kingdom
| | - Dmitry A Filatov
- Department of Plant Sciences, University of Oxford, Oxford, United Kingdom
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25
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Liu S, Li Y, Qin Z, Geng X, Bao L, Kaltenboeck L, Kucuktas H, Dunham R, Liu Z. High-density interspecific genetic linkage mapping provides insights into genomic incompatibility between channel catfish and blue catfish. Anim Genet 2015; 47:81-90. [PMID: 26537786 DOI: 10.1111/age.12372] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/30/2015] [Indexed: 02/01/2023]
Abstract
Catfish is the leading aquaculture species in the United States. The interspecific hybrid catfish produced by mating female channel catfish with male blue catfish outperform both of their parent species in a number of traits. However, mass production of the hybrids has been difficult because of reproductive isolation. Investigations of genome structure and organization of the hybrids provide insights into the genetic basis for maintenance of species divergence in the face of gene flow, thereby helping develop strategies for introgression and efficient production of the hybrids for aquaculture. In this study, we constructed a high-density genetic linkage map using the hybrid catfish system with the catfish 250K SNP array. A total of 26,238 SNPs were mapped to 29 linkage groups, with 12,776 unique marker positions. The linkage map spans approximately 3240 cM with an average intermarker distance of 0.25 cM. A fraction of markers (986 of 12,776) exhibited significant deviation from the expected Mendelian ratio of segregation, and they were clustered in major genomic blocks across 15 LGs, most notably LG9 and LG15. The distorted markers exhibited significant bias for maternal alleles among the backcross progenies, suggesting strong selection against the blue catfish alleles. The clustering of distorted markers within genomic blocks should lend insights into speciation as marked by incompatibilities between the two species. Such findings should also have profound implications for understanding the genomic evolution of closely related species as well as the introgression of hybrid production programs in aquaculture.
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Affiliation(s)
- S Liu
- The Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences and Program of Cell and Molecular Biosciences, Auburn University, Auburn, AL, 36849, USA
| | - Y Li
- The Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences and Program of Cell and Molecular Biosciences, Auburn University, Auburn, AL, 36849, USA
| | - Z Qin
- The Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences and Program of Cell and Molecular Biosciences, Auburn University, Auburn, AL, 36849, USA
| | - X Geng
- The Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences and Program of Cell and Molecular Biosciences, Auburn University, Auburn, AL, 36849, USA
| | - L Bao
- The Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences and Program of Cell and Molecular Biosciences, Auburn University, Auburn, AL, 36849, USA
| | - L Kaltenboeck
- The Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences and Program of Cell and Molecular Biosciences, Auburn University, Auburn, AL, 36849, USA
| | - H Kucuktas
- The Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences and Program of Cell and Molecular Biosciences, Auburn University, Auburn, AL, 36849, USA
| | - R Dunham
- The Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences and Program of Cell and Molecular Biosciences, Auburn University, Auburn, AL, 36849, USA
| | - Z Liu
- The Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences and Program of Cell and Molecular Biosciences, Auburn University, Auburn, AL, 36849, USA
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26
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Chapman MA, Hiscock SJ, Filatov DA. The genomic bases of morphological divergence and reproductive isolation driven by ecological speciation in Senecio (Asteraceae). J Evol Biol 2015; 29:98-113. [PMID: 26414668 DOI: 10.1111/jeb.12765] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Revised: 08/18/2015] [Accepted: 09/18/2015] [Indexed: 12/18/2022]
Abstract
Ecological speciation, driven by adaptation to contrasting environments, provides an attractive opportunity to study the formation of distinct species, and the role of selection and genomic divergence in this process. Here, we focus on a particularly clear-cut case of ecological speciation to reveal the genomic bases of reproductive isolation and morphological differences between closely related Senecio species, whose recent divergence within the last ~200,000 years was likely driven by the uplift of Mt. Etna (Sicily). These species form a hybrid zone, yet remain morphologically and ecologically distinct, despite active gene exchange. Here, we report a high-density genetic map of the Senecio genome and map hybrid breakdown to one large and several small quantitative trait loci (QTL). Loci under diversifying selection cluster in three 5 cM regions which are characterized by a significant increase in relative (F(ST)), but not absolute (d(XY)), interspecific differentiation. They also correspond to some of the regions of greatest marker density, possibly corresponding to 'cold-spots' of recombination, such as centromeres or chromosomal inversions. Morphological QTL for leaf and floral traits overlap these clusters. We also detected three genomic regions with significant transmission ratio distortion (TRD), possibly indicating accumulation of intrinsic genetic incompatibilities between these recently diverged species. One of the TRD regions overlapped with a cluster of high species differentiation, and another overlaps the large QTL for hybrid breakdown, indicating that divergence of these species may have occurred due to a complex interplay of ecological divergence and accumulation of intrinsic genetic incompatibilities.
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Affiliation(s)
- M A Chapman
- Department of Plant Sciences, University of Oxford, Oxford, UK.,Centre for Biological Sciences, University of Southampton, Southampton, UK
| | - S J Hiscock
- University of Oxford Botanic Garden, Rose Lane, Oxford, UK
| | - D A Filatov
- Department of Plant Sciences, University of Oxford, Oxford, UK
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27
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Crawford DJ, Doyle JJ, Soltis DE, Soltis PS, Wendel JF. Contemporary and future studies in plant speciation, morphological/floral evolution and polyploidy: honouring the scientific contributions of Leslie D. Gottlieb to plant evolutionary biology. Philos Trans R Soc Lond B Biol Sci 2014; 369:20130341. [PMID: 24958916 PMCID: PMC4071516 DOI: 10.1098/rstb.2013.0341] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Affiliation(s)
- Daniel J Crawford
- Department of Ecology and Evolutionary Biology, and Biodiversity Institute, University of Kansas, Lawrence, KS 66045, USA
| | - Jeffrey J Doyle
- L. H. Bailey Hortorium, Department of Plant Biology, Cornell University, Ithaca, NY 14853, USA
| | - Douglas E Soltis
- Department of Biology, University of Florida, Gainesville, FL 17 32611, USA
| | - Pamela S Soltis
- Florida Museum of Natural History, University of Florida, Gainesville, FL 17 32611, USA
| | - Jonathan F Wendel
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA 50011, USA
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28
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Abbott RJ, Brennan AC. Altitudinal gradients, plant hybrid zones and evolutionary novelty. Philos Trans R Soc Lond B Biol Sci 2014; 369:20130346. [PMID: 24958920 PMCID: PMC4071520 DOI: 10.1098/rstb.2013.0346] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Altitudinal gradients are characterized by steep changes of the physical and biotic environment that present challenges to plant adaptation throughout large parts of the world. Hybrid zones may form where related species inhabit different neighbouring altitudes and can facilitate interspecific gene flow and potentially the breakdown of species barriers. Studies of such hybrid zones can reveal much about the genetic basis of adaptation to environmental differences stemming from changes in altitude and the maintenance of species divergence in the face of gene flow. Furthermore, owing to recombination and transgressive effects, such hybrid zones can be sources of evolutionary novelty. We document plant hybrid zones associated with altitudinal gradients and emphasize similarities and differences in their structure. We then focus on recent studies of a hybrid zone between two Senecio species that occur at high and low altitude on Mount Etna, Sicily, showing how adaptation to local environments and intrinsic selection against hybrids act to maintain it. Finally, we consider the potential of altitudinal hybrid zones for generating evolutionary novelty through adaptive introgression and hybrid speciation. Examples of homoploid hybrid species of Senecio and Pinus that originated from altitudinal hybrid zones are discussed.
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Affiliation(s)
- Richard J Abbott
- School of Biology, University of St Andrews, St Andrews, Fife KY16 9TH, UK
| | - Adrian C Brennan
- School of Biology, University of St Andrews, St Andrews, Fife KY16 9TH, UK School of Biological and Biomedical Sciences, University of Durham, South Road, Durham DH1 3LE, UK
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