1
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Stone BW, Rodríguez-Peña RA, Wolfe AD. Testing hypotheses of hybrid taxon formation in the shrubby beardtongues (Penstemon subgenus Dasanthera). AMERICAN JOURNAL OF BOTANY 2023; 110:e16118. [PMID: 36480414 DOI: 10.1002/ajb2.16118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 08/29/2022] [Accepted: 08/30/2022] [Indexed: 06/17/2023]
Abstract
PREMISE Hybridization is increasingly being identified in the genomes of species across the tree of life, leading to a general recognition that hybridization plays an important role in the generation of species diversity. While hybridization may increase species diversity directly via the formation of new taxa through hybrid speciation, it may also act indirectly via the exchange of phenotypic and genetic variance between species, which may in turn stimulate future speciation events. METHODS Using high-throughput sequence data, we resolved phylogenetic relationships and investigated the role of hybridization as a diversification mechanism in the shrubby beardtongues (Penstemon subgenus Dasanthera), a group of North American wildflowers that has undergone a recent and rapid adaptive radiation. Specifically, we tested four hypotheses of hybrid taxon formation resulting from hybridization between P. davidsonii and P. fruticosus. RESULTS Species tree inference supports the monophyly of subgenus Dasanthera and elucidates relationships between taxa distributed in the Cascades and Sierra Nevada Mountains. Results also provide evidence of gene flow between P. davidsonii and P. fruticosus and support at least one hybrid origin hypothesis (P. davidsonii var. menziesii) in a region of contemporary distributional overlap. Hybridization may have also been facilitated by historical overlap in geographic distribution caused by species' responses to climatic changes during the Pleistocene. CONCLUSIONS Our results support a history of hybridization between focal taxa in a rapidly radiating clade of plants and more broadly contribute to our growing understanding of the role of hybridization as a diversification mechanism in plants.
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Affiliation(s)
- Benjamin W Stone
- Department of Evolution, Ecology, & Organismal Biology, The Ohio State University, Columbus, OH, 43210, USA
| | | | - Andrea D Wolfe
- Department of Evolution, Ecology, & Organismal Biology, The Ohio State University, Columbus, OH, 43210, USA
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2
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O'Donnell ST, Fitz-Gibbon ST, Sork VL. Ancient Introgression Between Distantly Related White Oaks (Quercus sect. Quercus) Shows Evidence of Climate-Associated Asymmetric Gene Exchange. J Hered 2021; 112:663-670. [PMID: 34508641 DOI: 10.1093/jhered/esab053] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 09/10/2021] [Indexed: 12/14/2022] Open
Abstract
Ancient introgression can be an important source of genetic variation that shapes the evolution and diversification of many taxa. Here, we estimate the timing, direction, and extent of gene flow between two distantly related oak species in the same section (Quercus sect. Quercus). We estimated these demographic events using genotyping by sequencing data, which generated 25 702 single nucleotide polymorphisms for 24 individuals of California scrub oak (Quercus berberidifolia) and 23 individuals of Engelmann oak (Quercus engelmannii). We tested several scenarios involving gene flow between these species using the diffusion approximation-based population genetic inference framework and model-testing approach of the Python package DaDi. We found that the most likely demographic scenario includes a bottleneck in Q. engelmannii that coincides with asymmetric gene flow from Q. berberidifolia into Q. engelmannii. Given that the timing of this gene flow coincides with the advent of a Mediterranean-type climate in the California Floristic Province, we propose that changing precipitation patterns and seasonality may have favored the introgression of climate-associated genes from the endemic into the non-endemic California oak.
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Affiliation(s)
- Scott T O'Donnell
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA, USA
| | - Sorel T Fitz-Gibbon
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA, USA
| | - Victoria L Sork
- Institute of the Environment and Sustainability, University of California, Los Angeles, CA, USA
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3
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Larson DA, Vargas OM, Vicentini A, Dick CW. Admixture may be extensive among hyperdominant Amazon rainforest tree species. THE NEW PHYTOLOGIST 2021; 232:2520-2534. [PMID: 34389989 PMCID: PMC9292926 DOI: 10.1111/nph.17675] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Accepted: 08/04/2021] [Indexed: 05/25/2023]
Abstract
Admixture is a mechanism by which species of long-lived plants may acquire novel alleles. However, the potential role of admixture in the origin and maintenance of tropical plant diversity is unclear. We ask whether admixture occurs in an ecologically important clade of Eschweilera (Parvifolia clade, Lecythidaceae), which includes some of the most widespread and abundant tree species in Amazonian forests. Using target capture sequencing, we conducted a detailed phylogenomic investigation of 33 species in the Parvifolia clade and investigated specific hypotheses of admixture within a robust phylogenetic framework. We found strong evidence of admixture among three ecologically dominant species, E. coriacea, E. wachenheimii and E. parviflora, but a lack of evidence for admixture among other lineages. Accepted species were largely distinguishable from one another, as was geographic structure within species. We show that hybridization may play a role in the evolution of the most widespread and ecologically variable Amazonian tree species. While admixture occurs among some species of Eschweilera, it has not led to widespread erosion of most species' genetic or morphological identities. Therefore, current morphological based species circumscriptions appear to provide a useful characterization of the clade's lineage diversity.
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Affiliation(s)
- Drew A. Larson
- Department of Ecology & Evolutionary BiologyUniversity of MichiganAnn ArborMI48109USA
| | - Oscar M. Vargas
- Department of Biological SciencesHumboldt State UniversityArcataCA95521USA
| | - Alberto Vicentini
- Instituto Nacional de Pesquisas da Amazônia (INPA)ManausAMCEP 69067‐375Brazil
| | - Christopher W. Dick
- Department of Ecology & Evolutionary BiologyUniversity of MichiganAnn ArborMI48109USA
- Smithsonian Tropical Research InstitutePanama CityRepublic of Panama
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4
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Zalmat AS, Sotola VA, Nice CC, Martin NH. Genetic structure in Louisiana Iris species reveals patterns of recent and historical admixture. AMERICAN JOURNAL OF BOTANY 2021; 108:2257-2268. [PMID: 34618352 DOI: 10.1002/ajb2.1758] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 08/10/2021] [Accepted: 08/18/2021] [Indexed: 06/13/2023]
Abstract
PREMISE When divergent lineages come into secondary contact, reproductive isolation may be incomplete, thus providing an opportunity to investigate how speciation is manifested in the genome. The Louisiana Irises (Iris, series Hexagonae) comprise a group of three or more ecologically and reproductively divergent lineages that can produce hybrids where they come into contact. We estimated standing genetic variation to understand the current distribution of population structure in the Louisiana Irises. METHODS We used genotyping-by-sequencing techniques to sample the genomes of Louisiana Iris species across their ranges. We sampled 20 populations (n = 632 individuals) across 11,249 loci and used Entropy and PCA models to assess population genetic data. RESULTS We discovered evidence for interspecific gene flow in parts of the range. Our analysis revealed patterns of population structure at odds with widely accepted nominal taxonomy. We discovered undescribed hybrid populations, designated as belonging to the I. brevicaulis lineage. Iris nelsonii shared significant ancestry with only one of the purported parent species, I. fulva, evidence inconsistent with a hybrid origin. CONCLUSIONS This study provides several key findings important to the investigation of standing genetic variation in the Louisiana Iris species complex. Compared to the other nominal species, I. brevicaulis contains a large amount of genetic diversity. In addition, we discovered a previously unknown hybrid zone between I. brevicaulis and I. hexagona along the Texas coast. Finally, our results do not support the long-standing hypothesis that I. nelsonii has mixed ancestry from three parental taxa.
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Affiliation(s)
- Alexander S Zalmat
- Department of Biology, Texas State University, San Marcos, Texas, 78666-0202, USA
| | - V Alex Sotola
- Department of Genetics, University of Georgia, Athens, Georgia, 30602-7223, USA
| | - Chris C Nice
- Department of Biology, Texas State University, San Marcos, Texas, 78666-0202, USA
| | - Noland H Martin
- Department of Biology, Texas State University, San Marcos, Texas, 78666-0202, USA
- Director of the Population and Conservation Biology Program, Department of Biology, Texas State University, San Marcos, Texas, 78666-0202, USA
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5
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Li Y, Wu DD. Finding unknown species in the genomes of extant species. J Genet Genomics 2021; 48:867-871. [PMID: 34509382 DOI: 10.1016/j.jgg.2021.05.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 05/21/2021] [Accepted: 05/23/2021] [Indexed: 11/18/2022]
Abstract
Although many species have gone extinct, their genetic components might exist in extant species because of ancient hybridization. Via advances in genome sequencing and development of modern population genetics, one can find the legacy of unknown or extinct species in the context of available genomes from extant species. Such discovery can be used as a strategy to search for hidden species or fossils in conservation biology and archeology, gain novel insight into complex evolutionary history, and provide the new sources of genetic variation for breeding and trait improvement in agriculture.
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Affiliation(s)
- Yan Li
- State Key Laboratory for Conservation and Utilization of Bio-resource in Yunnan and School of Life Science & School of Ecology and Environmental Science, Yunnan University, Kunming 650091, China.
| | - Dong-Dong Wu
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China; Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences, Kunming 650223, China
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6
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Cruzan MB, Thompson PG, Diaz NA, Hendrickson EC, Gerloff KR, Kline KA, Machiorlete HM, Persinger JM. Weak coupling among barrier loci and waves of neutral and adaptive introgression across an expanding hybrid zone. Evolution 2021; 75:3098-3114. [PMID: 34668193 PMCID: PMC9298192 DOI: 10.1111/evo.14381] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 09/14/2021] [Accepted: 09/19/2021] [Indexed: 01/02/2023]
Abstract
Hybridization can serve as an evolutionary stimulus, but we have little understanding of introgression at early stages of hybrid zone formation. We analyze reproductive isolation and introgression between a range‐limited and a widespread species. Reproductive barriers are estimated based on differences in flowering time, ecogeographic distributions, and seed set from crosses. We find an asymmetrical mating barrier due to cytonuclear incompatibility that is consistent with observed clusters of coincident and concordant tension zone clines (barrier loci) for mtDNA haplotypes and nuclear SNPs. These groups of concordant clines are spread across the hybrid zone, resulting in weak coupling among barrier loci and extensive introgression. Neutral clines had nearly equal introgression into both species’ ranges, whereas putative cases of adaptive introgression had exceptionally wide clines with centers shifted toward one species. Analyses of cline shape indicate that secondary contact was initiated within the last 800 generations with the per‐generation dispersal between 200 and 400 m, and provide some of the first estimates of the strength of selection required to account for observed levels of adaptive introgression. The weak species boundary between these species appears to be in early stages of dissolution, and ultimately will precipitate genetic swamping of the range‐limited species.
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Affiliation(s)
- Mitchell B Cruzan
- Department of Biology, Portland State University, Portland, Oregon, 97201
| | - Pamela G Thompson
- Department of Biology, Portland State University, Portland, Oregon, 97201
| | - Nicolas A Diaz
- Department of Biology, Portland State University, Portland, Oregon, 97201
| | | | - Katie R Gerloff
- Department of Biology, Portland State University, Portland, Oregon, 97201
| | - Katie A Kline
- Department of Biology, Portland State University, Portland, Oregon, 97201
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7
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Bautista C, Marsit S, Landry CR. Interspecific hybrids show a reduced adaptive potential under DNA damaging conditions. Evol Appl 2021; 14:758-769. [PMID: 33767750 PMCID: PMC7980265 DOI: 10.1111/eva.13155] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Accepted: 10/12/2020] [Indexed: 12/15/2022] Open
Abstract
Hybridization may increase the probability of adaptation to extreme stresses. This advantage could be caused by an increased genome plasticity in hybrids, which could accelerate the search for adaptive mutations. High ultraviolet (UV) radiation is a particular challenge in terms of adaptation because it affects the viability of organisms by directly damaging DNA, while also challenging future generations by increasing mutation rate. Here we test whether hybridization accelerates adaptive evolution in response to DNA damage, using yeast as a model. We exposed 180 populations of hybrids between species (Saccharomyces cerevisiae and Saccharomyces paradoxus) and their parental strains to UV mimetic and control conditions for approximately 100 generations. Although we found that adaptation occurs in both hybrids and parents, hybrids achieved a lower rate of adaptation, contrary to our expectations. Adaptation to DNA damage conditions comes with a large and similar cost for parents and hybrids, suggesting that this cost is not responsible for the lower adaptability of hybrids. We suggest that the lower adaptive potential of hybrids in this condition may result from the interaction between DNA damage and the inherent genetic instability of hybrids.
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Affiliation(s)
- Carla Bautista
- Institut de Biologie Intégrative et des Systèmes (IBIS)Université LavalQuébecQCCanada
- Département de BiologieFaculté des Sciences et de GénieUniversité LavalQuébecQCCanada
- Regroupement québécois de recherche sur la fonction, la structure et l'ingénierie des protéines (PROTEO)Université LavalQuébecQCCanada
- Centre de Recherche en Données Massives (CRDM)Université LavalQuébecQCCanada
| | - Souhir Marsit
- Institut de Biologie Intégrative et des Systèmes (IBIS)Université LavalQuébecQCCanada
- Département de BiologieFaculté des Sciences et de GénieUniversité LavalQuébecQCCanada
- Regroupement québécois de recherche sur la fonction, la structure et l'ingénierie des protéines (PROTEO)Université LavalQuébecQCCanada
- Centre de Recherche en Données Massives (CRDM)Université LavalQuébecQCCanada
| | - Christian R. Landry
- Institut de Biologie Intégrative et des Systèmes (IBIS)Université LavalQuébecQCCanada
- Département de BiologieFaculté des Sciences et de GénieUniversité LavalQuébecQCCanada
- Regroupement québécois de recherche sur la fonction, la structure et l'ingénierie des protéines (PROTEO)Université LavalQuébecQCCanada
- Centre de Recherche en Données Massives (CRDM)Université LavalQuébecQCCanada
- Département de Biochimie, de Microbiologie et de Bio‐informatiqueFaculté des Sciences et de GénieUniversité LavalQuébecQCCanada
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8
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Arida BL, Scopece G, Machado RM, Moraes AP, Forni-Martins E, Pinheiro F. Reproductive barriers and fertility of two neotropical orchid species and their natural hybrid. Evol Ecol 2021. [DOI: 10.1007/s10682-020-10095-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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9
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Akopyan M, Gompert Z, Klonoski K, Vega A, Kaiser K, Mackelprang R, Rosenblum EB, Robertson JM. Genetic and phenotypic evidence of a contact zone between divergent colour morphs of the iconic red-eyed treefrog. Mol Ecol 2020; 29:4442-4456. [PMID: 32945036 DOI: 10.1111/mec.15639] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 07/21/2020] [Accepted: 09/03/2020] [Indexed: 12/28/2022]
Abstract
Hybrid zones act as natural laboratories where divergent genomes interact, providing powerful systems for examining the evolutionary processes underlying biological diversity. In this study, we characterized patterns of genomic and phenotypic variation resulting from hybridization between divergent intraspecific lineages of the Neotropical red-eyed treefrog (Agalychnis callidryas). We found genetic evidence of a newly discovered contact zone and phenotypic novelty in leg colour-a trait suspected to play a role in mediating assortative mating in this species. Analysis of hybrid ancestry revealed an abundance of later-generation Fn individuals, suggesting persistence of hybrids in the contact zone. Hybrids are predominantly of southern ancestry but are phenotypically more similar to northern populations. Genome-wide association mapping revealed QTL with measurable effects on leg-colour variation, but further work is required to dissect the architecture of this trait and establish causal links. Further, genomic cline analyses indicated substantial variation in patterns of introgression across the genome. Directional introgression of loci associated with different aspects of leg colour are inherited from each parental lineage, creating a distinct hybrid colour pattern. We show that hybridization can generate new phenotypes, revealing the evolutionary processes that potentially underlie patterns of phenotypic diversity in this iconic polytypic frog. Our study is consistent with a role of hybridization and sexual selection in lineage diversification, evolutionary processes that have been implicated in accelerating divergence in the most phenotypically diverse species.
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Affiliation(s)
- Maria Akopyan
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, USA.,Department of Biology, California State University, Northridge, CA, USA
| | | | - Karina Klonoski
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA, USA
| | | | - Kristine Kaiser
- Department of Biology, California State University, Northridge, CA, USA
| | | | - Erica Bree Rosenblum
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA, USA
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10
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Nieto Feliner G, Casacuberta J, Wendel JF. Genomics of Evolutionary Novelty in Hybrids and Polyploids. Front Genet 2020; 11:792. [PMID: 32849797 PMCID: PMC7399645 DOI: 10.3389/fgene.2020.00792] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 07/03/2020] [Indexed: 12/15/2022] Open
Abstract
It has long been recognized that hybridization and polyploidy are prominent processes in plant evolution. Although classically recognized as significant in speciation and adaptation, recognition of the importance of interspecific gene flow has dramatically increased during the genomics era, concomitant with an unending flood of empirical examples, with or without genome doubling. Interspecific gene flow is thus increasingly thought to lead to evolutionary innovation and diversification, via adaptive introgression, homoploid hybrid speciation and allopolyploid speciation. Less well understood, however, are the suite of genetic and genomic mechanisms set in motion by the merger of differentiated genomes, and the temporal scale over which recombinational complexity mediated by gene flow might be expressed and exposed to natural selection. We focus on these issues here, considering the types of molecular genetic and genomic processes that might be set in motion by the saltational event of genome merger between two diverged species, either with or without genome doubling, and how these various processes can contribute to novel phenotypes. Genetic mechanisms include the infusion of new alleles and the genesis of novel structural variation including translocations and inversions, homoeologous exchanges, transposable element mobilization and novel insertional effects, presence-absence variation and copy number variation. Polyploidy generates massive transcriptomic and regulatory alteration, presumably set in motion by disrupted stoichiometries of regulatory factors, small RNAs and other genome interactions that cascade from single-gene expression change up through entire networks of transformed regulatory modules. We highlight both these novel combinatorial possibilities and the range of temporal scales over which such complexity might be generated, and thus exposed to natural selection and drift.
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Affiliation(s)
- Gonzalo Nieto Feliner
- Department of Biodiversity and Conservation, Real Jardín Botánico, CSIC, Madrid, Spain
| | - Josep Casacuberta
- Center for Research in Agricultural Genomics, CRAG (CSIC-IRTA-UAB-UB), Barcelona, Spain
| | - Jonathan F. Wendel
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA, United States
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11
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Smukowski Heil CS, Large CRL, Patterson K, Hickey ASM, Yeh CLC, Dunham MJ. Temperature preference can bias parental genome retention during hybrid evolution. PLoS Genet 2019; 15:e1008383. [PMID: 31525194 PMCID: PMC6762194 DOI: 10.1371/journal.pgen.1008383] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Revised: 09/26/2019] [Accepted: 08/22/2019] [Indexed: 11/18/2022] Open
Abstract
Interspecific hybridization can introduce genetic variation that aids in adaptation to new or changing environments. Here, we investigate how hybrid adaptation to temperature and nutrient limitation may alter parental genome representation over time. We evolved Saccharomyces cerevisiae x Saccharomyces uvarum hybrids in nutrient-limited continuous culture at 15°C for 200 generations. In comparison to previous evolution experiments at 30°C, we identified a number of responses only observed in the colder temperature regime, including the loss of the S. cerevisiae allele in favor of the cryotolerant S. uvarum allele for several portions of the hybrid genome. In particular, we discovered a genotype by environment interaction in the form of a loss of heterozygosity event on chromosome XIII; which species' haplotype is lost or maintained is dependent on the parental species' temperature preference and the temperature at which the hybrid was evolved. We show that a large contribution to this directionality is due to a temperature dependent fitness benefit at a single locus, the high affinity phosphate transporter gene PHO84. This work helps shape our understanding of what forces impact genome evolution after hybridization, and how environmental conditions may promote or disfavor the persistence of hybrids over time.
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Affiliation(s)
- Caiti S. Smukowski Heil
- Genome Sciences Department, University of Washington, Seattle, Washington, United States of America
| | - Christopher R. L. Large
- Genome Sciences Department, University of Washington, Seattle, Washington, United States of America
| | - Kira Patterson
- Genome Sciences Department, University of Washington, Seattle, Washington, United States of America
| | - Angela Shang-Mei Hickey
- Genome Sciences Department, University of Washington, Seattle, Washington, United States of America
| | - Chiann-Ling C. Yeh
- Genome Sciences Department, University of Washington, Seattle, Washington, United States of America
| | - Maitreya J. Dunham
- Genome Sciences Department, University of Washington, Seattle, Washington, United States of America
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12
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Presotto A, Hernández F, Mercer KL. Phenotypic selection under two contrasting environments in wild sunflower and its crop-wild hybrid. Evol Appl 2019; 12:1703-1717. [PMID: 31462924 PMCID: PMC6708420 DOI: 10.1111/eva.12828] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 05/16/2019] [Accepted: 05/23/2019] [Indexed: 01/20/2023] Open
Abstract
Hybridization is a common phenomenon in plants and can lead to the introgression of alleles from one population into another, generate new hybrid lineages, or cause species extinction. The environmental conditions and the genetic background of the participating populations may influence these outcomes since they can affect the fitness of hybrids, thereby increasing or decreasing the chances of introgression. Thus, it is important to understand the context-dependent prospects for introgression of alleles into diverse populations and under multiple ecological environments. Crop-wild hybridization presents an opportunity to explore these dynamics in agroecosystems. To this end, we used diverse wild and hybrid sunflowers from across the northern United States as a basis for evaluating variation in morphological traits and assessing context-dependent selection. These crop-wild hybrids and their wild counterparts were grown under agricultural conditions in the field with and without wheat competition. Interactions between origin and cross type affected expression of early functional traits, while interactions between competition and cross type acted on reproductive traits. A smattering of early and reproductive traits was affected by interactions between cross type and competition that varied by origin (i.e., 3-way interactions). Seven functional traits, especially number of branches and tertiary head diameter, underwent net and direct directional selection, while six out of these seven traits appear to also be experiencing nonlinear selection dynamics. In general, wild-like traits were favored under both sets of conditions, while, under wheat competition, some crop-like traits related to fast growth and primary head diameter became important. These data reaffirm the hypothesis that stressful conditions establish a scenario more suitable for crop introgression and clarify that nonlinear selection dynamics may play a role in this process.
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Affiliation(s)
- Alejandro Presotto
- Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS), Departamento de AgronomíaUniversidad Nacional del Sur (UNS)‐ CONICETBahía BlancaBuenos AiresArgentina
| | - Fernando Hernández
- Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS), Departamento de AgronomíaUniversidad Nacional del Sur (UNS)‐ CONICETBahía BlancaBuenos AiresArgentina
| | - Kristin L. Mercer
- Department of Horticulture and Crop ScienceOhio State UniversityColumbusOH
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13
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McRobie HR, Moncrief ND, Mundy NI. Multiple origins of melanism in two species of North American tree squirrel (Sciurus). BMC Evol Biol 2019; 19:140. [PMID: 31296164 PMCID: PMC6625063 DOI: 10.1186/s12862-019-1471-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 06/30/2019] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND While our understanding of the genetic basis of convergent evolution has improved there are still many uncertainties. Here we investigate the repeated evolution of dark colouration (melanism) in eastern fox squirrels (Sciurus niger; hereafter "fox squirrels") and eastern gray squirrels (S. carolinensis; hereafter "gray squirrels"). RESULTS We show that convergent evolution of melanism has arisen by independent genetic mechanisms in two populations of the fox squirrel. In a western population, melanism is associated with a 24 bp deletion in the melanocortin-1-receptor gene (MC1RΔ24 allele), whereas in a south-eastern population, melanism is associated with a point substitution in the agouti signalling protein gene causing a Gly121Cys mutation. The MC1R∆24 allele is also associated with melanism in gray squirrels, and, remarkably, all the MC1R∆24 haplotypes are identical in the two species. Evolutionary analyses show that the MC1R∆24 haplotype is more closely related to other MC1R haplotypes in the fox squirrel than in the gray squirrel. Modelling supports the possibility of gene flow between the two species. CONCLUSIONS The presence of the MC1R∆24 allele and melanism in gray squirrels is likely due to introgression from fox squirrels, although we cannot completely rule out alternative hypotheses including introgression from gray squirrels to fox squirrels, or an ancestral polymorphism. Convergent melanism in these two species of tree squirrels has evolved by at least two and probably three different evolutionary routes.
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Affiliation(s)
- Helen R McRobie
- School of Life Sciences, Anglia Ruskin University, Cambridge, CB1 1PT, UK.
| | - Nancy D Moncrief
- Virginia Museum of Natural History, Martinsville, VA, 24112, USA
| | - Nicholas I Mundy
- Department of Zoology, University of Cambridge, Cambridge, CB2 3EJ, UK
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14
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Wesselingh RA, Hořčicová Š, Mirzaei K. Fitness of reciprocal F
1
hybrids between
Rhinanthus minor
and
Rhinanthus major
under controlled conditions and in the field. J Evol Biol 2019; 32:931-942. [DOI: 10.1111/jeb.13492] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Revised: 04/25/2019] [Accepted: 05/24/2019] [Indexed: 12/25/2022]
Affiliation(s)
- Renate A. Wesselingh
- Biodiversity Research Centre Earth and Life Institute UCLouvain Louvain‐la‐Neuve Belgium
| | - Šárka Hořčicová
- Department of Botany Faculty of Science University of South Bohemia České Budějovice Czech Republic
| | - Khaled Mirzaei
- Biodiversity Research Centre Earth and Life Institute UCLouvain Louvain‐la‐Neuve Belgium
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15
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Abstract
Introgression is emerging as an important source of novel genetic variation, alongside standing variation and mutation. It is adaptive when such introgressed alleles are maintained by natural selection. Recently, there has been an explosion in the number of studies on adaptive introgression. In this review, we take a plant perspective centred on four lines of evidence: (i) introgression, (ii) selection, (iii) phenotype and (iv) fitness. While advances in genomics have contributed to our understanding of introgression and porous species boundaries (task 1), and the detection of signatures of selection in introgression (task 2), the investigation of adaptive introgression critically requires links to phenotypic variation and fitness (tasks 3 and 4). We also discuss the conservation implications of adaptive introgression in the face of climate change. Adaptive introgression is particularly important in rapidly changing environments, when standing genetic variation and mutation alone may only offer limited potential for adaptation. We conclude that clarifying the magnitude and fitness effects of introgression with improved statistical techniques, coupled with phenotypic evidence, has great potential for conservation and management efforts.
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Affiliation(s)
| | - Christian Lexer
- Department of Botany and Biodiversity Research, University of Vienna, Vienna, Austria
| | - Quentin C B Cronk
- Department of Botany, University of British Columbia, Vancouver, Canada
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Stanton DWG, Frandsen P, Waples RK, Heller R, Russo IRM, Orozco-terWengel PA, Pedersen CET, Siegismund HR, Bruford MW. More grist for the mill? Species delimitation in the genomic era and its implications for conservation. CONSERV GENET 2019. [DOI: 10.1007/s10592-019-01149-5] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Alex Sotola V, Ruppel DS, Bonner TH, Nice CC, Martin NH. Asymmetric introgression between fishes in the Red River basin of Texas is associated with variation in water quality. Ecol Evol 2019; 9:2083-2095. [PMID: 30847094 PMCID: PMC6392354 DOI: 10.1002/ece3.4901] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 12/05/2018] [Accepted: 12/13/2018] [Indexed: 01/01/2023] Open
Abstract
When ecologically divergent taxa encounter one another, hybrid zones can form when reproductive isolation is incomplete. The location of such hybrid zones can be influenced by environmental variables, and an ecological context can provide unique insights into the mechanisms by which species diverge and are maintained. Two ecologically differentiated species of small benthic fishes, the endemic and imperiled prairie chub, Macrhybopsis australis, and the shoal chub, Macrhybopsis hyostoma, are locally sympatric within the upper Red River Basin of Texas. We integrated population genomic data and environmental data to investigate species divergence and the maintenance of species boundaries in these two species. We found evidence of advanced-generation asymmetric hybridization and introgression, with shoal chub alleles introgressing more frequently into prairie chubs than the reciprocal. Using a Bayesian Genomic Cline framework, patterns of genomic introgression were revealed to be quite heterogeneous, yet shoal chub alleles were found to have likely selectively introgressed across species boundaries significantly more often than prairie chub alleles, potentially explaining some of the observed asymmetry in hybridization. These patterns were remarkably consistent across two sampled geographic regions of hybridization. Several environmental variables were found to significantly predict individual admixture, suggesting ecological isolation might maintain species boundaries.
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Affiliation(s)
| | | | | | - Chris C. Nice
- Biology DepartmentTexas State UniversitySan MarcosTexas
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18
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Burgarella C, Barnaud A, Kane NA, Jankowski F, Scarcelli N, Billot C, Vigouroux Y, Berthouly-Salazar C. Adaptive Introgression: An Untapped Evolutionary Mechanism for Crop Adaptation. FRONTIERS IN PLANT SCIENCE 2019; 10:4. [PMID: 30774638 PMCID: PMC6367218 DOI: 10.3389/fpls.2019.00004] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 01/04/2019] [Indexed: 05/18/2023]
Abstract
Global environmental changes strongly impact wild and domesticated species biology and their associated ecosystem services. For crops, global warming has led to significant changes in terms of phenology and/or yield. To respond to the agricultural challenges of this century, there is a strong need for harnessing the genetic variability of crops and adapting them to new conditions. Gene flow, from either the same species or a different species, may be an immediate primary source to widen genetic diversity and adaptions to various environments. When the incorporation of a foreign variant leads to an increase of the fitness of the recipient pool, it is referred to as "adaptive introgression". Crop species are excellent case studies of this phenomenon since their genetic variability has been considerably reduced over space and time but most of them continue exchanging genetic material with their wild relatives. In this paper, we review studies of adaptive introgression, presenting methodological approaches and challenges to detecting it. We pay particular attention to the potential of this evolutionary mechanism for the adaptation of crops. Furthermore, we discuss the importance of farmers' knowledge and practices in shaping wild-to-crop gene flow. Finally, we argue that screening the wild introgression already existing in the cultivated gene pool may be an effective strategy for uncovering wild diversity relevant for crop adaptation to current environmental changes and for informing new breeding directions.
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Affiliation(s)
- Concetta Burgarella
- Institut de Recherche pour le Développement, UMR DIADE, Montpellier, France
- DIADE, Université de Montpellier, Montpellier, France
- Centre de Coopération Internationale en Recherche Agronomique pour le Développement, UMR AGAP, Montpellier, France
- AGAP, Université de Montpellier, Centre de Coopération Internationale en Recherche Agronomique pour le Développement, Institut National de la Recherche Agronomique, Montpellier SupAgro, Montpellier, France
- *Correspondence: Concetta Burgarella, Cécile Berthouly-Salazar,
| | - Adeline Barnaud
- Institut de Recherche pour le Développement, UMR DIADE, Montpellier, France
- DIADE, Université de Montpellier, Montpellier, France
| | - Ndjido Ardo Kane
- Laboratoire National de Recherches sur les Productions Végétales, Institut Sénégalais de Recherches Agricoles, Dakar, Senegal
- Laboratoire Mixte International Adaptation des Plantes et Microorganismes Associés aux Stress Environnementaux, Dakar, Senegal
| | - Frédérique Jankowski
- Centre de Coopération Internationale en Recherche Agronomique pour le Développement, UPR GREEN, Montpellier, France
- GREEN, Centre de Coopération Internationale en Recherche Agronomique pour le Développement, Université de Montpellier, Montpellier, France
- Bureau d’Analyses Macro-Economiques, Institut Sénégalais de Recherches Agricoles, Dakar, Senegal
| | - Nora Scarcelli
- Institut de Recherche pour le Développement, UMR DIADE, Montpellier, France
- DIADE, Université de Montpellier, Montpellier, France
| | - Claire Billot
- Centre de Coopération Internationale en Recherche Agronomique pour le Développement, UMR AGAP, Montpellier, France
- AGAP, Université de Montpellier, Centre de Coopération Internationale en Recherche Agronomique pour le Développement, Institut National de la Recherche Agronomique, Montpellier SupAgro, Montpellier, France
| | - Yves Vigouroux
- Institut de Recherche pour le Développement, UMR DIADE, Montpellier, France
- DIADE, Université de Montpellier, Montpellier, France
| | - Cécile Berthouly-Salazar
- Institut de Recherche pour le Développement, UMR DIADE, Montpellier, France
- DIADE, Université de Montpellier, Montpellier, France
- Laboratoire Mixte International Adaptation des Plantes et Microorganismes Associés aux Stress Environnementaux, Dakar, Senegal
- *Correspondence: Concetta Burgarella, Cécile Berthouly-Salazar,
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Gramlich S, Wagner ND, Hörandl E. RAD-seq reveals genetic structure of the F 2-generation of natural willow hybrids (Salix L.) and a great potential for interspecific introgression. BMC PLANT BIOLOGY 2018; 18:317. [PMID: 30509159 PMCID: PMC6276181 DOI: 10.1186/s12870-018-1552-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 11/21/2018] [Indexed: 05/23/2023]
Abstract
BACKGROUND Hybridization of species with porous genomes can eventually lead to introgression via repeated backcrossing. The potential for introgression between species is reflected by the extent of segregation distortion in later generation hybrids. Here we studied a population of hybrids between Salix purpurea and S. helvetica that has emerged within the last 30 years on a glacier forefield in the European Alps due to secondary contact of the parental species. We used 5758 biallelic SNPs produced by RAD sequencing with the aim to ascertain the predominance of backcrosses (F1 hybrid x parent) or F2 hybrids (F1 hybrid x F1 hybrid) among hybrid offspring. Further, the SNPs were used to study segregation distortion in the second hybrid generation. RESULTS The analyses in STRUCTURE and NewHybrids revealed that the population consisted of parents and F1 hybrids, whereas hybrid offspring consisted mainly of backcrosses to either parental species, but also some F2 hybrids. Although there was a clear genetic differentiation between S. purpurea and S. helvetica (FST = 0.24), there was no significant segregation distortion in the backcrosses or the F2 hybrids. Plant height of the backcrosses resembled the respective parental species, whereas F2 hybrids were more similar to the subalpine S. helvetica. CONCLUSIONS The co-occurrence of the parental species and the hybrids on the glacier forefield, the high frequency of backcrossing, and the low resistance to gene flow via backcrossing make a scenario of introgression in this young hybrid population highly likely, potentially leading to the transfer of adaptive traits. We further suggest that this willow hybrid population may serve as a model for the evolutionary processes initiated by recent global warming.
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Affiliation(s)
- Susanne Gramlich
- Department of Systematics, Biodiversity and Evolution of Plants (with Herbarium), University Goettingen, Untere Karspüle 2, 37073 Goettingen, Germany
| | - Natascha Dorothea Wagner
- Department of Systematics, Biodiversity and Evolution of Plants (with Herbarium), University Goettingen, Untere Karspüle 2, 37073 Goettingen, Germany
| | - Elvira Hörandl
- Department of Systematics, Biodiversity and Evolution of Plants (with Herbarium), University Goettingen, Untere Karspüle 2, 37073 Goettingen, Germany
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20
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Sassone AB, Giussani LM. Reconstructing the phylogenetic history of the tribe Leucocoryneae (Allioideae): Reticulate evolution and diversification in South America. Mol Phylogenet Evol 2018; 127:437-448. [DOI: 10.1016/j.ympev.2018.04.034] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Revised: 04/08/2018] [Accepted: 04/21/2018] [Indexed: 12/13/2022]
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21
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Suarez-Gonzalez A, Hefer CA, Lexer C, Cronk QCB, Douglas CJ. Scale and direction of adaptive introgression between black cottonwood (Populus trichocarpa) and balsam poplar (P. balsamifera). Mol Ecol 2018; 27:1667-1680. [DOI: 10.1111/mec.14561] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Revised: 02/17/2018] [Accepted: 02/23/2018] [Indexed: 12/31/2022]
Affiliation(s)
| | - Charles A. Hefer
- Department of Botany; University of British Columbia; Vancouver BC Canada
| | - Christian Lexer
- Department of Botany and Biodiversity Research; University of Vienna; Vienna Austria
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22
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Hybridization and differential introgression associated with environmental shifts in a mistletoe species complex. Sci Rep 2018; 8:5591. [PMID: 29615778 PMCID: PMC5882953 DOI: 10.1038/s41598-018-23707-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 03/12/2018] [Indexed: 12/22/2022] Open
Abstract
Host specialization after host shifting is traditionally viewed as the pathway to speciation in parasitic plants. However, geographical and environmental changes can also influence parasite speciation, through hybridization processes. Here we investigated the impact of past climatic fluctuations, environment, and host shifts on the genetic structure and patterns of hybridization and gene flow between Psittacanthus calyculatus and P. schiedeanus, a Mesoamerican species complex. Using microsatellites (408 individuals), we document moderate genetic diversity but high genetic differentiation between widespread parental clusters, calyculatus in dry pine-oak forests and schiedeanus in cloud forests. Bayesian analyses identified a third cluster, with admixture between parental clusters in areas of xeric and tropical dry forests and high levels of migration rates following secondary contact. Coincidently host associations in these areas differ from those in areas of parental species, suggesting that past hybridization played a role in environmental and host shifts. Overall, the observed genetic and geographic patterns suggest that these Psittacanthus populations could have entered a distinct evolutionary pathway. The results provide evidence for highlights on the importance of the Pleistocene climate changes, habitat differences, and potential host shifts in the evolutionary history of Neotropical mistletoes.
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23
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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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24
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Lau CLF, Jacobs DK. Introgression between ecologically distinct species following increased salinity in the Colorado Delta- Worldwide implications for impacted estuary diversity. PeerJ 2017; 5:e4056. [PMID: 29250463 PMCID: PMC5731342 DOI: 10.7717/peerj.4056] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Accepted: 10/27/2017] [Indexed: 11/20/2022] Open
Abstract
We investigate hybridization and introgression between ecologically distinct sister species of silverside fish in the Gulf of California through combined analysis of morphological, sequence, and genotypic data. Water diversions in the past century turned the Colorado River Delta from a normal estuary to a hypersaline inverse estuary, raising concerns for the local fauna, much of which is endangered. Salinity differences are known to generate ecological species pairs and we anticipated that loss of the fresher-water historic salinity regime could alter the adaptive factors maintaining distinction between the broadly distributed Gulf-endemic Colpichthys regis and the narrowly restricted Delta-endemic Colpichthys hubbsi, the species that experienced dramatic environmental change. In this altered environmental context, these long-isolated species (as revealed by Cytochrome b sequences) show genotypic (RAG1, microsatellites) evidence of active hybridization where the species ranges abut, as well as directional introgression from C. regis into the range center of C. hubbsi. Bayesian group assignment (STRUCTURE) on six microsatellite loci and multivariate analyses (DAPC) on both microsatellites and phenotypic data further support substantial recent admixture between the sister species. Although we find no evidence for recent population decline in C. hubbsi based on mitochondrial sequence, introgression may be placing an ancient ecological species at risk of extinction. Such introgressive extinction risk should also pertain to other ecological species historically sustained by the now changing Delta environment. More broadly, salinity gradient associated ecological speciation is evident in silverside species pairs in many estuarine systems around the world. Ecological species pairs among other taxa in such systems are likely poorly understood or cryptic. As water extraction accelerates in river systems worldwide, salinity gradients will necessarily be altered, impacting many more estuary and delta systems. Such alteration of habitats will place biodiversity at risk not only from direct effects of habitat destruction, but also from the potential for the breakdown of ecological species. Thus, evolutionary response to the anthropogenic alteration of salinity gradients in estuaries merits investigation as the number of impacted systems increases around the globe, permitting parallel study of multiple systems, while also permitting a conservation management response to help preserve this little championed component of biodiversity.
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Affiliation(s)
- Clive L F Lau
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA, United States of America
| | - David K Jacobs
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA, United States of America
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25
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Albertin W, Chernova M, Durrens P, Guichoux E, Sherman DJ, Masneuf-Pomarede I, Marullo P. Many interspecific chromosomal introgressions are highly prevalent in HolarcticSaccharomyces uvarumstrains found in human-related fermentations. Yeast 2017; 35:141-156. [DOI: 10.1002/yea.3248] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 07/26/2017] [Accepted: 07/29/2017] [Indexed: 01/12/2023] Open
Affiliation(s)
- Warren Albertin
- Université Bordeaux; ISVV, Unité de recherche OEnologie EA 4577, USC 1366 INRA, Bordeaux INP; 33140 Villenave d'Ornon France
- ENSCBP; Bordeaux INP; 33600 Pessac France
| | - Maria Chernova
- Université Bordeaux; ISVV, Unité de recherche OEnologie EA 4577, USC 1366 INRA, Bordeaux INP; 33140 Villenave d'Ornon France
| | - Pascal Durrens
- CNRS UMR 5800; Univ. Bordeaux; 33405 Talence France
- Inria Bordeaux Sud-Ouest; joint team Pleiade Inria/INRA/CNRS; 33405 Talence France
| | - Erwan Guichoux
- INRA; UMR1202 Biodiversité Gènes et Ecosystèmes, Plateforme Génomique; Cestas 33610 France
| | - David James Sherman
- CNRS UMR 5800; Univ. Bordeaux; 33405 Talence France
- Inria Bordeaux Sud-Ouest; joint team Pleiade Inria/INRA/CNRS; 33405 Talence France
| | - Isabelle Masneuf-Pomarede
- Université Bordeaux; ISVV, Unité de recherche OEnologie EA 4577, USC 1366 INRA, Bordeaux INP; 33140 Villenave d'Ornon France
- Bordeaux Sciences Agro; 33170 Gradignan France
| | - Philippe Marullo
- Université Bordeaux; ISVV, Unité de recherche OEnologie EA 4577, USC 1366 INRA, Bordeaux INP; 33140 Villenave d'Ornon France
- Biolaffort; 33100 Bordeaux France
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26
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Blackburn GS, Brunet BMT, Muirhead K, Cusson M, Béliveau C, Levesque RC, Lumley LM, Sperling FAH. Distinct sources of gene flow produce contrasting population genetic dynamics at different range boundaries of aChoristoneurabudworm. Mol Ecol 2017; 26:6666-6684. [DOI: 10.1111/mec.14386] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 09/26/2017] [Accepted: 10/07/2017] [Indexed: 12/14/2022]
Affiliation(s)
- Gwylim S. Blackburn
- Department of Biological Sciences; CW405 Biosciences Centre; University of Alberta; Edmonton AB Canada
- Laurentian Forestry Centre; Natural Resources Canada; Canadian Forest Service; Quebec City QC Canada
- Institut de Biologie Intégrative et des Systèmes (IBIS); Université Laval; Québec QC Canada
| | - Bryan M. T. Brunet
- Department of Biological Sciences; CW405 Biosciences Centre; University of Alberta; Edmonton AB Canada
| | - Kevin Muirhead
- Department of Biological Sciences; CW405 Biosciences Centre; University of Alberta; Edmonton AB Canada
| | - Michel Cusson
- Laurentian Forestry Centre; Natural Resources Canada; Canadian Forest Service; Quebec City QC Canada
| | - Catherine Béliveau
- Laurentian Forestry Centre; Natural Resources Canada; Canadian Forest Service; Quebec City QC Canada
| | - Roger C. Levesque
- Institut de Biologie Intégrative et des Systèmes (IBIS); Université Laval; Québec QC Canada
| | - Lisa M. Lumley
- Department of Biological Sciences; CW405 Biosciences Centre; University of Alberta; Edmonton AB Canada
- Laurentian Forestry Centre; Natural Resources Canada; Canadian Forest Service; Quebec City QC Canada
| | - Felix A. H. Sperling
- Department of Biological Sciences; CW405 Biosciences Centre; University of Alberta; Edmonton AB Canada
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27
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Enciso-Romero J, Pardo-Díaz C, Martin SH, Arias CF, Linares M, McMillan WO, Jiggins CD, Salazar C. Evolution of novel mimicry rings facilitated by adaptive introgression in tropical butterflies. Mol Ecol 2017; 26:5160-5172. [PMID: 28777894 DOI: 10.1111/mec.14277] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 07/25/2017] [Accepted: 07/31/2017] [Indexed: 12/25/2022]
Abstract
Understanding the genetic basis of phenotypic variation and the mechanisms involved in the evolution of adaptive novelty, especially in adaptive radiations, is a major goal in evolutionary biology. Here, we used whole-genome sequence data to investigate the origin of the yellow hindwing bar in the Heliconius cydno radiation. We found modular variation associated with hindwing phenotype in two narrow noncoding regions upstream and downstream of the cortex gene, which was recently identified as a pigmentation pattern controller in multiple species of Heliconius. Genetic variation at each of these modules suggests an independent control of the dorsal and ventral hindwing patterning, with the upstream module associated with the ventral phenotype and the downstream module with the dorsal one. Furthermore, we detected introgression between H. cydno and its closely related species Heliconius melpomene in these modules, likely allowing both species to participate in novel mimicry rings. In sum, our findings support the role of regulatory modularity coupled with adaptive introgression as an elegant mechanism by which novel phenotypic combinations can evolve and fuel an adaptive radiation.
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Affiliation(s)
- Juan Enciso-Romero
- Biology Program, Faculty of Natural Sciences and Mathematics, Universidad del Rosario, Bogotá D.C, Colombia
| | - Carolina Pardo-Díaz
- Biology Program, Faculty of Natural Sciences and Mathematics, Universidad del Rosario, Bogotá D.C, Colombia
| | - Simon H Martin
- Department of Zoology, University of Cambridge, Cambridge, UK
| | - Carlos F Arias
- Biology Program, Faculty of Natural Sciences and Mathematics, Universidad del Rosario, Bogotá D.C, Colombia.,Smithsonian Tropical Research Institute, Balboa, Ancon, Panama
| | - Mauricio Linares
- Biology Program, Faculty of Natural Sciences and Mathematics, Universidad del Rosario, Bogotá D.C, Colombia
| | | | - Chris D Jiggins
- Department of Zoology, University of Cambridge, Cambridge, UK
| | - Camilo Salazar
- Biology Program, Faculty of Natural Sciences and Mathematics, Universidad del Rosario, Bogotá D.C, Colombia
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28
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Ning H, Yu J, Gong X. Bidirectional natural hybridization between sympatric Ligularia vellerea and L. subspicata. PLANT DIVERSITY 2017; 39:214-220. [PMID: 30159514 PMCID: PMC6112292 DOI: 10.1016/j.pld.2017.07.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2017] [Revised: 07/05/2017] [Accepted: 07/12/2017] [Indexed: 05/14/2023]
Abstract
Natural hybridization has been regarded as a crucial pathway of speciation and provides the raw materials for the evolution of biodiversity. The interspecific natural hybridization of the genus Ligularia Cass. is universal and has been considered to be an important factor driving the high diversity of Ligularia species in the Hengduan Mountains, China. Although the natural hybridization between L. vellerea and L. subspicata was reported previously, the direction of hybridization was uncertain due to the limitation of sampling. Thus, in this study, we sampled more individuals and increased two fragments of chloroplast DNA on the basis of the previous study to further verify the natural hybridization between L. vellerea and L. subspicata and confirm the direction of hybridization. Based on DNA sequences (atpB-rbcL, trnL-rpl32, trnQ-5'rps16, and nuclear ribosomal internal transcribed spacer region) data, we concluded that putative hybrids were primary products of hybridization between L. vellerea and L. subspicata and the hybridization was bidirectional. Moreover, sympatric L. tongolensis was not apparently involved in the hybridization. Surprisingly, some pure L. subspicata individuals showed the disaccordance between morphology and DNA data, which might indicate that introgression occurs between L. vellerea and L. subspicata.
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Affiliation(s)
- Huai Ning
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jiaojun Yu
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China
| | - Xun Gong
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China
- Corresponding author. No. 132, Lanhei Road, Panlong District, Kunming City, Yunnan Province, China. Fax: +86 871 65223625.
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29
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de Lafontaine G, Bousquet J. Asymmetry matters: A genomic assessment of directional biases in gene flow between hybridizing spruces. Ecol Evol 2017; 7:3883-3893. [PMID: 28616185 PMCID: PMC5468134 DOI: 10.1002/ece3.2682] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 11/16/2016] [Accepted: 11/20/2016] [Indexed: 01/08/2023] Open
Abstract
Assessing directional bias in interspecific gene flow might be important in determining the evolutionary trajectory of closely related species pairs. Using a set of 300 single nucleotide polymorphisms (SNPs) having variable propensity to cross species boundary, we evaluated the genomic extent and direction of interspecific gene flow in a progenitor‐derivative spruce species pair (black spruce and red spruce). A higher rate of gene flow was found from black spruce toward red spruce purebreds than vice versa. This asymmetry could reflect the historical gene flow between the two taxa at the time of species inception and during postglacial colonization. A clear asymmetry in introgression was depicted by a greater gene flow between red spruce and hybrids than between black spruce and hybrids. While backcrossing toward red spruce was invariably high across the genome, the actual species boundary is between hybrids and black spruce where gene flow is impeded at those genomic regions impermeable to introgression. Associations between hybrid index and climatic variables (total annual precipitation and mean annual temperature) were tested, as these might indicate a role for exogenous selection in maintaining the species boundary. While an apparent association was found between the hybrid index and precipitation, it collapsed when considered in light of the directional bias in interspecific gene flow. Hence, considering asymmetrical patterns of introgression allowed us to falsify an apparent role for exogenous selection. Although this was not formerly tested here, we suggest that this pattern could result from asymmetrical endogenous selection, a contention that deserves further investigations.
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Affiliation(s)
- Guillaume de Lafontaine
- Canada Research Chair in Forest Genomics Centre for Forest Research and Institute of Systems and Integrative Biology Université Laval Québec QC Canada.,Department of Plant Biology University of Illinois Urbana IL USA
| | - Jean Bousquet
- Canada Research Chair in Forest Genomics Centre for Forest Research and Institute of Systems and Integrative Biology Université Laval Québec QC Canada
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30
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Pieper SJ, Nicholls AA, Freeland JR, Dorken ME. Asymmetric Hybridization in Cattails (Typha spp.) and Its Implications for the Evolutionary Maintenance of Native Typha latifolia. J Hered 2017; 108:479-487. [DOI: 10.1093/jhered/esx036] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Accepted: 04/12/2017] [Indexed: 12/11/2022] Open
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31
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Leroy T, Roux C, Villate L, Bodénès C, Romiguier J, Paiva JAP, Dossat C, Aury JM, Plomion C, Kremer A. Extensive recent secondary contacts between four European white oak species. THE NEW PHYTOLOGIST 2017; 214:865-878. [PMID: 28085203 PMCID: PMC5624484 DOI: 10.1111/nph.14413] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Accepted: 11/21/2016] [Indexed: 05/04/2023]
Abstract
Historical trajectories of tree species during the late Quaternary have been well reconstructed through genetic and palaeobotanical studies. However, many congeneric tree species are interfertile, and the timing and contribution of introgression to species divergence during their evolutionary history remains largely unknown. We quantified past and current gene flow events between four morphologically divergent oak species (Quercus petraea, Q. robur, Q. pyrenaica, Q. pubescens), by two independent inference methods: diffusion approximation to the joint frequency spectrum (∂a∂i) and approximate Bayesian computation (ABC). For each pair of species, alternative scenarios of speciation allowing gene flow over different timescales were evaluated. Analyses of 3524 single nucleotide polymorphisms (SNPs) randomly distributed in the genome, showed that these species evolved in complete isolation for most of their history, but recently came into secondary contact, probably facilitated by the most recent period of postglacial warming. We demonstrated that: there was sufficient genetic differentiation before secondary contact for the accumulation of barriers to gene flow; and current European white oak genomes are a mosaic of genes that have crossed species boundaries and genes impermeable to gene flow.
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Affiliation(s)
- Thibault Leroy
- BIOGECO, INRA, Université de Bordeaux, Cestas, 33610, France
| | - Camille Roux
- Department of Ecology and Evolution, University of Lausanne, Lausanne, 1015, Switzerland
| | - Laure Villate
- BIOGECO, INRA, Université de Bordeaux, Cestas, 33610, France
| | | | - Jonathan Romiguier
- Department of Ecology and Evolution, University of Lausanne, Lausanne, 1015, Switzerland
| | - Jorge A P Paiva
- Instituto de Biologia Experimental e Tecnológica, iBET, Apartado 12, Oeiras, 2780-901, Portugal
- Institute of Plant Genetics, Polish Academy of Sciences, 34 Strzeszynska street, Poznań, PL-60-479, Poland
| | - Carole Dossat
- Institut de Genomique (IG), Commissariat à l'Energie Atomique (CEA), Genoscope, Evry, 91057, France
| | - Jean-Marc Aury
- Institut de Genomique (IG), Commissariat à l'Energie Atomique (CEA), Genoscope, Evry, 91057, France
| | | | - Antoine Kremer
- BIOGECO, INRA, Université de Bordeaux, Cestas, 33610, France
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32
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Guinand B, Vandeputte M, Dupont-Nivet M, Vergnet A, Haffray P, Chavanne H, Chatain B. Metapopulation patterns of additive and nonadditive genetic variance in the sea bass ( Dicentrarchus labrax). Ecol Evol 2017; 7:2777-2790. [PMID: 28428868 PMCID: PMC5395432 DOI: 10.1002/ece3.2832] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Revised: 12/19/2016] [Accepted: 01/28/2017] [Indexed: 01/30/2023] Open
Abstract
Describing and explaining the geographic within‐species variation in phenotypes (“phenogeography”) in the sea over a species distribution range is central to our understanding of a variety of eco‐evolutionary topics. However, phenogeographic studies that have a large potential to investigate adaptive variation are overcome by phylogeographic studies, still mainly focusing on neutral markers. How genotypic and phenotypic data could covary over large geographic scales remains poorly understood in marine species. We crossed 75 noninbred sires (five origins) and 26 dams (two origins; each side of a hybrid zone) in a factorial diallel cross in order to investigate geographic variation for early survival and sex ratio in the metapopulation of the European sea bass (Dicentrarchus labrax), a highly prized marine fish species. Full‐sib families (N = 1,950) were produced and reared in a common environment. Parentage assignment of 7,200 individuals was performed with seven microsatellite markers. Generalized linear models showed significant additive effects for both traits and pleiotropy between traits. A significant nonadditive genetic effect was detected. Different expression of traits and distinct relative performances were found for reciprocal crosses involving populations located on each side of the main hybrid zone located at the Almeria‐Oran front, illustrating asymmetric reproductive isolation. The poor fitness performance observed for the Western Mediterranean population of sea bass is discussed as it represents the main source of seed hatchery production, but also because it potentially illustrates nonadaptive introgression and maladaptation.
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Affiliation(s)
- Bruno Guinand
- Département Biologie-Ecologie Université de Montpellier Montpellier France.,UMR CNRS IRD EPHE UM Institut des Sciences de l'Evolution de Montpellier Montpellier France
| | - Marc Vandeputte
- INRA UMR 1313 GABI Domaine de Vilvert Jouy-en-Josas France.,Ifremer UMR 9190 Marine Biodiversity, Exploitation and Conservation Palavas-les-Flots France
| | | | - Alain Vergnet
- Ifremer UMR 9190 Marine Biodiversity, Exploitation and Conservation Palavas-les-Flots France
| | | | - Hervé Chavanne
- Istituto Sperimentale Lazzaro Spallanzani Rivolta d'Adda Italy
| | - Béatrice Chatain
- Ifremer UMR 9190 Marine Biodiversity, Exploitation and Conservation Palavas-les-Flots France
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33
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Hamlin JAP, Simmonds TJ, Arnold ML. Niche Conservatism for Ecological Preference in the Louisiana iris species complex. Biol J Linn Soc Lond 2017; 120:144-154. [PMID: 32742021 DOI: 10.1111/bij.12884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Spatial and temporal environmental variation influences evolutionary processes such as divergence among populations and species. Here, we investigate the patterns of niche evolution for the Louisiana irises as well as understanding the phylogenetic relationship between these species. Using BEAST, a species phylogeny was generated for the Louisiana irises in order to test the hypothesis of whether niche conservatism has played an important role for this species complex. Species Distribution Models were constructed for present day distributions to determine the environmental factors, which contribute to species ranges. Tests of niche similarity were performed in order to evaluate if niche conservatism is apparent within this species complex. We demonstrate that the Louisiana iris species complex is a monophyletic clade with I. brevicaulis and I. fulva as being sister to each other. The differences observed among the iris species, in regard to associated environmental factors suggest an effect from these components on the distributions and habitats occupied. Furthermore, tests of niche similarity indicate niche conservatism for all species comparisons. Working at the species level and assessing various factors that can influence differentiation, this study assessed a more complete picture of the ecological and evolutionary history of this species complex across their geographic and ecological range.
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Affiliation(s)
| | - Tyler J Simmonds
- 120 E. Green St. Department of Genetics, University of Georgia Athens, GA, 30602, USA
| | - Michael L Arnold
- 120 E. Green St. Department of Genetics, University of Georgia Athens, GA, 30602, USA
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34
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Pacheco-Sierra G, Gompert Z, Domínguez-Laso J, Vázquez-Domínguez E. Genetic and morphological evidence of a geographically widespread hybrid zone between two crocodile species,Crocodylus acutusandCrocodylus moreletii. Mol Ecol 2016; 25:3484-98. [DOI: 10.1111/mec.13694] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Revised: 04/07/2016] [Accepted: 05/02/2016] [Indexed: 12/21/2022]
Affiliation(s)
- Gualberto Pacheco-Sierra
- Departamento de Ecología de la Biodiversidad; Instituto de Ecología; Universidad Nacional Autónoma de México; Ap. Postal 70-275 Ciudad Universitaria México DF 04510 México
- Posgrado en Ciencias Biológicas; Universidad Nacional Autónoma de México; Coyoacán México DF 04510 México
| | - Zachariah Gompert
- Department of Biology and Ecology Center; Utah State University; Logan UT 84322 USA
| | | | - Ella Vázquez-Domínguez
- Departamento de Ecología de la Biodiversidad; Instituto de Ecología; Universidad Nacional Autónoma de México; Ap. Postal 70-275 Ciudad Universitaria México DF 04510 México
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35
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Kenney AM, Sweigart AL. Reproductive isolation and introgression between sympatric
Mimulus
species. Mol Ecol 2016; 25:2499-517. [DOI: 10.1111/mec.13630] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Revised: 03/18/2016] [Accepted: 03/22/2016] [Indexed: 01/19/2023]
Affiliation(s)
- Amanda M. Kenney
- Department of Genetics University of Georgia Athens GA 30602 USA
- Department of Biological Sciences St. Edward's University Austin TX 78704 USA
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36
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Tigano A, Friesen VL. Genomics of local adaptation with gene flow. Mol Ecol 2016; 25:2144-64. [DOI: 10.1111/mec.13606] [Citation(s) in RCA: 241] [Impact Index Per Article: 30.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 02/22/2016] [Accepted: 03/01/2016] [Indexed: 12/14/2022]
Affiliation(s)
- Anna Tigano
- Department of Biology; Queen's University; Kingston ON K7L 3N6 Canada
| | - Vicki L. Friesen
- Department of Biology; Queen's University; Kingston ON K7L 3N6 Canada
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37
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Suarez-Gonzalez A, Hefer CA, Christe C, Corea O, Lexer C, Cronk QCB, Douglas CJ. Genomic and functional approaches reveal a case of adaptive introgression fromPopulus balsamifera(balsam poplar) inP. trichocarpa(black cottonwood). Mol Ecol 2016; 25:2427-42. [DOI: 10.1111/mec.13539] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Revised: 01/02/2016] [Accepted: 01/06/2016] [Indexed: 01/14/2023]
Affiliation(s)
| | - Charles A. Hefer
- Department of Botany; University of British Columbia; Vancouver BC V6T 1Z4 Canada
| | - Camille Christe
- Unit of Ecology & Evolution; Department of Biology; University of Fribourg; CH-1700 Fribourg Switzerland
| | - Oliver Corea
- Department of Biology and Centre for Forest Biology; University of Victoria; Victoria BC V8W 3N5 Canada
| | - Christian Lexer
- Unit of Ecology & Evolution; Department of Biology; University of Fribourg; CH-1700 Fribourg Switzerland
- Department of Botany and Biodiversity Research; University of Vienna; A-1030 Vienna Austria
| | - Quentin C. B. Cronk
- Department of Botany; University of British Columbia; Vancouver BC V6T 1Z4 Canada
| | - Carl J. Douglas
- Department of Botany; University of British Columbia; Vancouver BC V6T 1Z4 Canada
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38
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Zhang W, Dasmahapatra KK, Mallet J, Moreira GRP, Kronforst MR. Genome-wide introgression among distantly related Heliconius butterfly species. Genome Biol 2016; 17:25. [PMID: 26921238 PMCID: PMC4769579 DOI: 10.1186/s13059-016-0889-0] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2015] [Accepted: 01/28/2016] [Indexed: 12/30/2022] Open
Abstract
Background Although hybridization is thought to be relatively rare in animals, the raw genetic material introduced via introgression may play an important role in fueling adaptation and adaptive radiation. The butterfly genus Heliconius is an excellent system to study hybridization and introgression but most studies have focused on closely related species such as H. cydno and H. melpomene. Here we characterize genome-wide patterns of introgression between H. besckei, the only species with a red and yellow banded ‘postman’ wing pattern in the tiger-striped silvaniform clade, and co-mimetic H. melpomene nanna. Results We find a pronounced signature of putative introgression from H. melpomene into H. besckei in the genomic region upstream of the gene optix, known to control red wing patterning, suggesting adaptive introgression of wing pattern mimicry between these two distantly related species. At least 39 additional genomic regions show signals of introgression as strong or stronger than this mimicry locus. Gene flow has been on-going, with evidence of gene exchange at multiple time points, and bidirectional, moving from the melpomene to the silvaniform clade and vice versa. The history of gene exchange has also been complex, with contributions from multiple silvaniform species in addition to H. besckei. We also detect a signature of ancient introgression of the entire Z chromosome between the silvaniform and melpomene/cydno clades. Conclusions Our study provides a genome-wide portrait of introgression between distantly related butterfly species. We further propose a comprehensive and efficient workflow for gene flow identification in genomic data sets. Electronic supplementary material The online version of this article (doi:10.1186/s13059-016-0889-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Wei Zhang
- Department of Ecology & Evolution, University of Chicago, Chicago, IL, 60637, USA.
| | | | - James Mallet
- Department of Organismic & Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Gilson R P Moreira
- Departamento de Zoologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, 91501-970, Brazil
| | - Marcus R Kronforst
- Department of Ecology & Evolution, University of Chicago, Chicago, IL, 60637, USA.
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de Lafontaine G, Prunier J, Gérardi S, Bousquet J. Tracking the progression of speciation: variable patterns of introgression across the genome provide insights on the species delimitation between progenitor-derivative spruces (Picea mariana×P. rubens). Mol Ecol 2015; 24:5229-47. [DOI: 10.1111/mec.13377] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Revised: 08/05/2015] [Accepted: 09/01/2015] [Indexed: 01/17/2023]
Affiliation(s)
- Guillaume de Lafontaine
- Canada Research Chair in Forest and Environmental Genomics; Centre for Forest Research and Institute of Systems and Integrative Biology; Université Laval; 1030 Avenue de la Médecine Québec QC G1V 0A6 Canada
| | - Julien Prunier
- Canada Research Chair in Forest and Environmental Genomics; Centre for Forest Research and Institute of Systems and Integrative Biology; Université Laval; 1030 Avenue de la Médecine Québec QC G1V 0A6 Canada
| | - Sébastien Gérardi
- Canada Research Chair in Forest and Environmental Genomics; Centre for Forest Research and Institute of Systems and Integrative Biology; Université Laval; 1030 Avenue de la Médecine Québec QC G1V 0A6 Canada
| | - Jean Bousquet
- Canada Research Chair in Forest and Environmental Genomics; Centre for Forest Research and Institute of Systems and Integrative Biology; Université Laval; 1030 Avenue de la Médecine Québec QC G1V 0A6 Canada
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40
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Hülber K, Sonnleitner M, Suda J, Krejčíková J, Schönswetter P, Schneeweiss GM, Winkler M. Ecological differentiation, lack of hybrids involving diploids, and asymmetric gene flow between polyploids in narrow contact zones of Senecio carniolicus (syn. Jacobaea carniolica, Asteraceae). Ecol Evol 2015; 5:1224-34. [PMID: 25859328 PMCID: PMC4377266 DOI: 10.1002/ece3.1430] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2014] [Revised: 01/27/2015] [Accepted: 01/28/2015] [Indexed: 11/09/2022] Open
Abstract
Areas of immediate contact of different cytotypes offer a unique opportunity to study evolutionary dynamics within heteroploid species and to assess isolation mechanisms governing coexistence of cytotypes of different ploidy. The degree of reproductive isolation of cytotypes, that is, the frequency of heteroploid crosses and subsequent formation of viable and (partly) fertile hybrids, plays a crucial role for the long-term integrity of lineages in contact zones. Here, we assessed fine-scale distribution, spatial clustering, and ecological niches as well as patterns of gene flow in parental and hybrid cytotypes in zones of immediate contact of di-, tetra-, and hexaploid Senecio carniolicus (Asteraceae) in the Eastern Alps. Cytotypes were spatially separated also at the investigated microscale; the strongest spatial separation was observed for the fully interfertile tetra- and hexaploids. The three main cytotypes showed highly significant niche differences, which were, however, weaker than across their entire distribution ranges in the Eastern Alps. Individuals with intermediate ploidy levels were found neither in the diploid/tetraploid nor in the diploid/hexaploid contact zones indicating strong reproductive barriers. In contrast, pentaploid individuals were frequent in the tetraploid/hexaploid contact zone, albeit limited to a narrow strip in the immediate contact zone of their parental cytotypes. AFLP fingerprinting data revealed introgressive gene flow mediated by pentaploid hybrids from tetra- to hexaploid individuals, but not vice versa. The ecological niche of pentaploids differed significantly from that of tetraploids but not from hexaploids.
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Affiliation(s)
- Karl Hülber
- Division of Conservation Biology, Vegetation Ecology and Landscape Ecology, Department of Botany and Biodiversity Research, University of ViennaVienna, Austria
- Vienna Institute for Nature Conservation & AnalysesVienna, Austria
| | - Michaela Sonnleitner
- Division of Conservation Biology, Vegetation Ecology and Landscape Ecology, Department of Botany and Biodiversity Research, University of ViennaVienna, Austria
| | - Jan Suda
- Department of Botany, Faculty of Science, Charles University in PraguePrague, Czech Republic
- Institute of Botany, The Czech Academy of SciencesPrůhonice, Czech Republic
| | - Jana Krejčíková
- Department of Botany, Faculty of Science, Charles University in PraguePrague, Czech Republic
| | | | - Gerald M Schneeweiss
- Division of Systematics and Evolutionary Botany, Department of Botany and Biodiversity Research, University of ViennaVienna, Austria
| | - Manuela Winkler
- Division of Systematics and Evolutionary Botany, Department of Botany and Biodiversity Research, University of ViennaVienna, Austria
- GLORIA co-ordination, Center for Global Change and Sustainability, University of Natural Resources and Life Sciences ViennaVienna, Austria
- Institute for Interdisciplinary Mountain Research, Austrian Academy of SciencesInnsbruck, Austria
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41
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Bono JM, Matzkin LM, Hoang K, Brandsmeier L. Molecular evolution of candidate genes involved in post-mating-prezygotic reproductive isolation. J Evol Biol 2015; 28:403-14. [PMID: 25522894 DOI: 10.1111/jeb.12574] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Revised: 12/11/2014] [Accepted: 12/13/2014] [Indexed: 12/13/2022]
Abstract
Traits involved in post-copulatory interactions between the sexes may evolve rapidly as a result of sexual selection and/or sexual conflict, leading to post-mating-prezygotic (PMPZ) reproductive isolating barriers between diverging lineages. Although the importance of PMPZ isolation is recognized, the molecular basis of such incompatibilities is not well understood. Here, we investigate molecular evolution of a subset of Drosophila mojavensis and Drosophila arizonae reproductive tract genes. These include genes that are transcriptionally regulated by conspecific mating in females, many of which are misregulated in heterospecific crosses, and a set of male genes whose transcripts are transferred to females during mating. As a group, misregulated female genes are not more divergent and do not appear to evolve under different selection pressures than other female reproductive genes. Male transferred genes evolve at a higher rate than testis-expressed genes, and at a similar rate compared to accessory gland protein genes, which are known to evolve rapidly. Four of the individual male transferred genes show patterns of divergent positive selection between D. mojavensis and D. arizonae. Three of the four genes belong to the sperm-coating protein-like family, including an ortholog of antares, which influences female fertility and receptivity in Drosophila melanogaster. Synthesis of these molecular evolutionary analyses with transcriptomics and predicted functional information makes these genes candidates for involvement in PMPZ reproductive incompatibilities between D. mojavensis and D. arizonae.
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Affiliation(s)
- J M Bono
- Biology Department, University of Colorado Colorado Springs, Colorado Springs, CO, USA
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42
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Whitney KD, Broman KW, Kane NC, Hovick SM, Randell RA, Rieseberg LH. Quantitative trait locus mapping identifies candidate alleles involved in adaptive introgression and range expansion in a wild sunflower. Mol Ecol 2015; 24:2194-211. [PMID: 25522096 DOI: 10.1111/mec.13044] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Revised: 12/05/2014] [Accepted: 12/12/2014] [Indexed: 01/14/2023]
Abstract
The wild North American sunflowers Helianthus annuus and H. debilis are participants in one of the earliest identified examples of adaptive trait introgression, and the exchange is hypothesized to have triggered a range expansion in H. annuus. However, the genetic basis of the adaptive exchange has not been examined. Here, we combine quantitative trait locus (QTL) mapping with field measurements of fitness to identify candidate H. debilis QTL alleles likely to have introgressed into H. annuus to form the natural hybrid lineage H. a. texanus. Two 500-individual BC1 mapping populations were grown in central Texas, genotyped for 384 single nucleotide polymorphism (SNP) markers and then phenotyped in the field for two fitness and 22 herbivore resistance, ecophysiological, phenological and architectural traits. We identified a total of 110 QTL, including at least one QTL for 22 of the 24 traits. Over 75% of traits exhibited at least one H. debilis QTL allele that would shift the trait in the direction of the wild hybrid H. a. texanus. We identified three chromosomal regions where H. debilis alleles increased both female and male components of fitness; these regions are expected to be strongly favoured in the wild. QTL for a number of other ecophysiological, phenological and architectural traits colocalized with these three regions and are candidates for the actual traits driving adaptive shifts. G × E interactions played a modest role, with 17% of the QTL showing potentially divergent phenotypic effects between the two field sites. The candidate adaptive chromosomal regions identified here serve as explicit hypotheses for how the genetic architecture of the hybrid lineage came into existence.
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Affiliation(s)
- Kenneth D Whitney
- Department of Biology, University of New Mexico, Albuquerque, NM, 87131-0001, USA
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43
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Heo JY, Feng D, Niu X, Mitchell-Olds T, van Tienderen PH, Tomes D, Schranz ME. Identification of quantitative trait loci and a candidate locus for freezing tolerance in controlled and outdoor environments in the overwintering crucifer Boechera stricta. PLANT, CELL & ENVIRONMENT 2014; 37:2459-69. [PMID: 24811132 PMCID: PMC4416058 DOI: 10.1111/pce.12365] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Revised: 04/21/2014] [Accepted: 04/22/2014] [Indexed: 05/29/2023]
Abstract
Development of chilling and freezing tolerance is complex and can be affected by photoperiod, temperature and photosynthetic performance; however, there has been limited research on the interaction of these three factors. We evaluated 108 recombinant inbred lines of Boechera stricta, derived from a cross between lines originating from Montana and Colorado, under controlled long day (LD), short-day (SD) and in an outdoor environment (OE). We measured maximum quantum yield of photosystem II, lethal temperature for 50% survival and electrolyte leakage of leaves. Our results revealed significant variation for chilling and freezing tolerance and photosynthetic performance in different environments. Using both single- and multi-trait analyses, three main-effect quantitative trait loci (QTL) were identified. QTL on linkage group (LG)3 were SD specific, whereas QTL on LG4 were found under both LD and SD. Under all conditions, QTL on LG7 were identified, but were particularly predictive for the outdoor experiment. The co-localization of photosynthetic performance and freezing tolerance effects supports these traits being co-regulated. Finally, the major QTL on LG7 is syntenic to the Arabidopsis C-repeat binding factor locus, known regulators of chilling and freezing responses in Arabidopsis thaliana and other species.
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Affiliation(s)
- Jae-Yun Heo
- Biosystematics Group, Wageningen University & Research Center, Wageningen, the Netherlands
| | - Dongsheng Feng
- Pioneer Hi-Bred International, Inc., a DuPont Business, Johnston, USA
| | - Xiaomu Niu
- Pioneer Hi-Bred International, Inc., a DuPont Business, Johnston, USA
| | | | - Peter H. van Tienderen
- Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, the Netherlands
| | - Dwight Tomes
- Pioneer Hi-Bred International, Inc., a DuPont Business, Johnston, USA
| | - M. Eric Schranz
- Biosystematics Group, Wageningen University & Research Center, Wageningen, the Netherlands
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44
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Mimura M, Mishima M, Lascoux M, Yahara T. Range shift and introgression of the rear and leading populations in two ecologically distinct Rubus species. BMC Evol Biol 2014; 2014:209. [PMID: 25344198 PMCID: PMC4221717 DOI: 10.1186/s12862-014-0209-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Accepted: 09/23/2014] [Indexed: 11/15/2022] Open
Abstract
Background The margins of a species’ range might be located at the margins of a species’ niche, and in such cases, can be highly vulnerable to climate changes. They, however, may also undergo significant evolutionary changes due to drastic population dynamics in response to climate changes, which may increase the chances of isolation and contact among species. Such species interactions induced by climate changes could then regulate or facilitate further responses to climatic changes. We hypothesized that climate changes lead to species contacts and subsequent genetic exchanges due to differences in population dynamics at the species boundaries. We sampled two closely related Rubus species, one temperate (Rubus palmatus) and the other subtropical (R. grayanus) near their joint species boundaries in southern Japan. Coalescent analysis, based on molecular data and ecological niche modelling during the Last Glacial Maximum (LGM), were used to infer past population dynamics. At the contact zones on Yakushima (Yaku Island), where the two species are parapatrically distributed, we tested hybridization along altitudinal gradients. Results Coalescent analysis suggested that the southernmost populations of R. palmatus predated the LGM (~20,000 ya). Conversely, populations at the current northern limit of R. grayanus diverged relatively recently and likely represent young outposts of a northbound range shift. These population dynamics were partly supported by the ensemble forecasting of six different species distribution models. Both past and ongoing hybridizations were detected near and on Yakushima. Backcrosses and advanced-generation hybrids likely generated the clinal hybrid zones along altitudinal gradients on the island where the two species are currently parapatrically distributed. Conclusions Climate oscillations during the Quaternary Period and the response of a species in range shifts likely led to repeated contacts with the gene pools of ecologically distinct relatives. Such species interactions, induced by climate changes, may bring new genetic material to the marginal populations where species tend to experience more extreme climatic conditions at the margins of the species distribution. Electronic supplementary material The online version of this article (doi:10.1186/s12862-014-0209-9) contains supplementary material, which is available to authorized users.
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45
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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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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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47
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Melo MC, Grealy A, Brittain B, Walter GM, Ortiz-Barrientos D. Strong extrinsic reproductive isolation between parapatric populations of an Australian groundsel. THE NEW PHYTOLOGIST 2014; 203:323-334. [PMID: 24684207 DOI: 10.1111/nph.12779] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Accepted: 02/20/2014] [Indexed: 06/03/2023]
Abstract
Speciation with gene flow, or the evolution of reproductive isolation between interbreeding populations, remains a controversial problem in evolution. This is because gene flow erodes the adaptive differences that selection creates between populations. Here, we use a combination of common garden experiments in the field and in the glasshouse to investigate what ecological and genetic mechanisms prevent gene flow and maintain morphological and genetic differentiation between coastal parapatric populations of the Australian groundsel Senecio lautus. We discovered that in each habitat extrinsic reproductive barriers prevented gene flow, whereas intrinsic barriers in F1 hybrids were weak. In the field, herbivores played a major role in preventing gene flow, but glasshouse experiments demonstrated that soil type also created variable selective pressures both locally and on a greater geographic scale. Our experimental results demonstrate that interfertile plant populations adapting to contrasting environments may diverge as a consequence of concurrent natural selection acting against migrants and hybrids through multiple mechanisms. These results provide novel insights into the consequences of local adaptation in the origin of strong barriers to gene flow in plants, and suggest that herbivory may play an important role in the early stages of plant speciation.
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Affiliation(s)
- Maria C Melo
- School of Biological Sciences, The University of Queensland, St Lucia, Queensland, 4072, Australia
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48
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Hartman Y, Hooftman DAP, Uwimana B, Schranz ME, van de Wiel CCM, Smulders MJM, Visser RGF, Michelmore RW, van Tienderen PH. Abiotic stress QTL in lettuce crop-wild hybrids: comparing greenhouse and field experiments. Ecol Evol 2014; 4:2395-409. [PMID: 25360276 PMCID: PMC4203288 DOI: 10.1002/ece3.1060] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Revised: 03/03/2014] [Accepted: 03/11/2014] [Indexed: 11/11/2022] Open
Abstract
The development of stress-tolerant crops is an increasingly important goal of current crop breeding. A higher abiotic stress tolerance could increase the probability of introgression of genes from crops to wild relatives. This is particularly relevant to the discussion on the risks of new GM crops that may be engineered to increase abiotic stress resistance. We investigated abiotic stress QTL in greenhouse and field experiments in which we subjected recombinant inbred lines from a cross between cultivated Lactuca sativa cv. Salinas and its wild relative L. serriola to drought, low nutrients, salt stress, and aboveground competition. Aboveground biomass at the end of the rosette stage was used as a proxy for the performance of plants under a particular stress. We detected a mosaic of abiotic stress QTL over the entire genome with little overlap between QTL from different stresses. The two QTL clusters that were identified reflected general growth rather than specific stress responses and colocated with clusters found in earlier studies for leaf shape and flowering time. Genetic correlations across treatments were often higher among different stress treatments within the same experiment (greenhouse or field), than among the same type of stress applied in different experiments. Moreover, the effects of the field stress treatments were more correlated with those of the greenhouse competition treatments than to those of the other greenhouse stress experiments, suggesting that competition rather than abiotic stress is a major factor in the field. In conclusion, the introgression risk of stress tolerance (trans-)genes under field conditions cannot easily be predicted based on genomic background selection patterns from controlled QTL experiments in greenhouses, especially field data will be needed to assess potential (negative) ecological effects of introgression of these transgenes into wild relatives.
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Affiliation(s)
- Yorike Hartman
- Institute for Biodiversity and Ecosystem Dynamics, Universiteit van Amsterdam Amsterdam, The Netherlands
| | - Danny A P Hooftman
- Institute for Biodiversity and Ecosystem Dynamics, Universiteit van Amsterdam Amsterdam, The Netherlands ; NERC, Centre for Ecology and Hydrology Wallingford, UK
| | - Brigitte Uwimana
- Wageningen UR Plant Breeding, Wageningen University and Research Centre Wageningen, The Netherlands
| | - M Eric Schranz
- Institute for Biodiversity and Ecosystem Dynamics, Universiteit van Amsterdam Amsterdam, The Netherlands
| | - Clemens C M van de Wiel
- Wageningen UR Plant Breeding, Wageningen University and Research Centre Wageningen, The Netherlands
| | - Marinus J M Smulders
- Wageningen UR Plant Breeding, Wageningen University and Research Centre Wageningen, The Netherlands
| | - Richard G F Visser
- Wageningen UR Plant Breeding, Wageningen University and Research Centre Wageningen, The Netherlands
| | - Richard W Michelmore
- Genome Center and Department of Plant Sciences, University of California Davis, California
| | - Peter H van Tienderen
- Institute for Biodiversity and Ecosystem Dynamics, Universiteit van Amsterdam Amsterdam, The Netherlands
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49
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Hamlin JAP, Arnold ML. Determining population structure and hybridization for two iris species. Ecol Evol 2014; 4:743-55. [PMID: 24683457 PMCID: PMC3967900 DOI: 10.1002/ece3.964] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Revised: 12/20/2013] [Accepted: 01/08/2014] [Indexed: 12/24/2022] Open
Abstract
Identifying processes that promote or limit gene flow can help define the ecological and evolutionary history of a species. Furthermore, defining those factors that make up “species boundaries” can provide a definition of the independent evolutionary trajectories of related taxa. For many species, the historic processes that account for their distribution of genetic variation remain unresolved. In this study, we examine the geographic distribution of genetic diversity for two species of Louisiana Irises, Iris brevicaulis and Iris fulva. Specifically, we asked how populations are structured and if population structure coincides with potential barriers to gene flow. We also asked whether there is evidence of hybridization between these two species outside Louisiana hybrid zones. We used a genotyping-by-sequencing approach and sampled a large number of single nucleotide polymorphisms across these species' genomes. Two different population assignment methods were used to resolve population structure in I. brevicaulis; however, there was considerably less population structure in I. fulva. We used a species tree approach to infer phylogenies both within and between populations and species. For I. brevicaulis, the geography of the collection locality was reflected in the phylogeny. The I. fulva phylogeny reflected much less structure than detected for I. brevicaulis. Lastly, combining both species into a phylogenetic analysis resolved two of six populations of I. brevicaulis that shared alleles with I. fulva. Taken together, our results suggest major differences in the level and pattern of connectivity among populations of these two Louisiana Iris species.
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Affiliation(s)
- Jennafer A P Hamlin
- Correspondence Jennafer A. P. Hamlin, Department of Genetics, University of Georgia, 120 East Green St. Davison Life Sciences Building, Athens, GA. Tel: 706 410 7529; Fax: 706 542 3910; E-mail:
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50
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De La Torre AR, Wang T, Jaquish B, Aitken SN. Adaptation and exogenous selection in a Picea glauca × Picea engelmannii hybrid zone: implications for forest management under climate change. THE NEW PHYTOLOGIST 2014; 201:687-699. [PMID: 24200028 PMCID: PMC4285121 DOI: 10.1111/nph.12540] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Accepted: 08/30/2013] [Indexed: 05/04/2023]
Abstract
The nature of selection responsible for the maintenance of the economically and ecologically important Picea glauca × Picea engelmannii hybrid zone was investigated. Genomic, phenotypic and climatic data were used to test assumptions of hybrid zone maintenance and to model future scenarios under climate change. Genome-wide estimates of admixture based on a panel of 86 candidate gene single nucleotide polymorphisms were combined with long-term quantitative data on growth and survival (over 20 yr), as well as one-time assessments of bud burst and bud set phenology, and cold hardiness traits. A total of 15,498 individuals were phenotyped for growth and survival. Our results suggest that the P. glauca × P. engelmannii hybrid zone is maintained by local adaptation to growing season length and snowpack (exogenous selection). Hybrids appeared to be fitter than pure species in intermediate environments, which fits expectations of the bounded hybrid superiority model of hybrid zone maintenance. Adaptive introgression from parental species has probably contributed to increased hybrid fitness in intermediate habitats. While P. engelmannii ancestry is higher than P. glauca ancestry in hybrid populations, on average, selective breeding in managed hybrid populations is shifting genomic composition towards P. glauca, potentially pre-adapting managed populations to warmer climates.
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Affiliation(s)
- Amanda R De La Torre
- Centre for Forest Conservation Genetics, Department of Forest and Conservation Sciences, University of British Columbia3041–2424 Main Mall, Vancouver, BC, V6T1Z4, Canada
- Department of Ecology and Environmental Sciences, Umeå UniversityLinneaus väg 6, SE-901 87, Umeå, Sweden
- Author for correspondence:Amanda R. De La Torre, Tel: +46 090 7865475,
| | - Tongli Wang
- Centre for Forest Conservation Genetics, Department of Forest and Conservation Sciences, University of British Columbia3041–2424 Main Mall, Vancouver, BC, V6T1Z4, Canada
| | - Barry Jaquish
- Kalamalka Forestry Centre, Tree Improvement Branch, BC Ministry of Forests, Lands & Natural Resource Operations3401 Reservoir Rd, Vernon, BC, V1B2C7, Canada
| | - Sally N Aitken
- Centre for Forest Conservation Genetics, Department of Forest and Conservation Sciences, University of British Columbia3041–2424 Main Mall, Vancouver, BC, V6T1Z4, Canada
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