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Le Provost G, Brachi B, Lesur I, Lalanne C, Labadie K, Aury JM, Da Silva C, Postolache D, Leroy T, Plomion C. Gene expression and genetic divergence in oak species highlight adaptive genes to soil water constraints. PLANT PHYSIOLOGY 2022; 190:2466-2483. [PMID: 36066428 PMCID: PMC9706432 DOI: 10.1093/plphys/kiac420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 08/13/2022] [Indexed: 06/15/2023]
Abstract
Drought and waterlogging impede tree growth and may even lead to tree death. Oaks, an emblematic group of tree species, have evolved a range of adaptations to cope with these constraints. The two most widely distributed European species, pedunculate (PO; Quercus robur L.) and sessile oak (SO; Quercus petraea Matt. Lieb), have overlapping ranges, but their respective distribution are highly constrained by local soil conditions. These contrasting ecological preferences between two closely related and frequently hybridizing species constitute a powerful model to explore the functional bases of the adaptive responses in oak. We exposed oak seedlings to waterlogging and drought, conditions typically encountered by the two species in their respective habitats, and studied changes in gene expression in roots using RNA-seq. We identified genes that change in expression between treatments differentially depending on species. These "species × environment"-responsive genes revealed adaptive molecular strategies involving adventitious and lateral root formation, aerenchyma formation in PO, and osmoregulation and ABA regulation in SO. With this experimental design, we also identified genes with different expression between species independently of water conditions imposed. Surprisingly, this category included genes with functions consistent with a role in intrinsic reproductive barriers. Finally, we compared our findings with those for a genome scan of species divergence and found that the expressional candidate genes included numerous highly differentiated genetic markers between the two species. By combining transcriptomic analysis, gene annotation, pathway analyses, as well as genome scan for genetic differentiation among species, we were able to highlight loci likely involved in adaptation of the two species to their respective ecological niches.
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Affiliation(s)
| | | | - Isabelle Lesur
- INRAE, Univ. Bordeaux, BIOGECO, Cestas, F-33610, France
- Helix Venture, Mérignac, F-33700, France
| | | | - Karine Labadie
- Genoscope, Institut de Biologie François-Jacob, Commissariat à l'Energie Atomique (CEA), Université Paris-Saclay, Evry, 91057, France
| | - Jean-Marc Aury
- Génomique Métabolique, Genoscope, Institut François Jacob, CEA, CNRS, Univ Evry, Université Paris-Saclay, Evry, 91057, France
| | - Corinne Da Silva
- Génomique Métabolique, Genoscope, Institut François Jacob, CEA, CNRS, Univ Evry, Université Paris-Saclay, Evry, 91057, France
| | - Dragos Postolache
- National Institute for Research and Development in Forestry “Marin Drăcea”, Cluj Napoca Research Station, Cluj-Napoca, 400202, Romania
| | - Thibault Leroy
- INRAE, Univ. Bordeaux, BIOGECO, Cestas, F-33610, France
- IRHS-UMR1345, Université d’Angers, INRAE, Institut Agro, Beaucouzé, 49071, France
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Mandeville EG, Hall RO, Buerkle CA. Ecological outcomes of hybridization vary extensively in Catostomus fishes. Evolution 2022; 76:2697-2711. [PMID: 36097356 PMCID: PMC9801484 DOI: 10.1111/evo.14624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 07/20/2022] [Accepted: 07/26/2022] [Indexed: 01/22/2023]
Abstract
Hybridization outcomes vary geographically and can depend on the environment. Hybridization can also reshape biotic interactions, leading to ecological shifts. If hybrids function differently ecologically in ways that enhance or reduce fitness, and those ecological roles vary geographically, ecological factors might explain variation in hybridization outcomes. However, relatively few studies have focused on ecological traits of hybrids. We compared the feeding ecology of Catostomus fish species and hybrids by using stable isotopes (δ13 C and δ15 N) as a proxy for diet and habitat use, and compared two native species, an introduced species, and three interspecific hybrid crosses. We included hybrids and parental species from seven rivers where hybridization outcomes vary. Relative isotopic niches of native species varied geographically, but native species did not fully overlap in isotopic space in any river sampled, suggesting little overlap of resource use between historically sympatric species. The introduced species overlapped with one or both native species in every river, suggesting similar resource use and potential competition. Hybrids occupied intermediate, matching, or more transgressive isotopic niches, and varied within and among rivers. Ecological outcomes of hybridization varied across locations, implying that hybridization might have unpredictable, idiosyncratic ecological effects.
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Affiliation(s)
- Elizabeth G. Mandeville
- Department of Integrative Biology, University of Guelph, Guelph, Ontario Canada
- Department of Botany, University of Wyoming, Laramie, Wyoming USA
- Program in Ecology, University of Wyoming, Laramie, Wyoming USA
| | - Robert O. Hall
- Program in Ecology, University of Wyoming, Laramie, Wyoming USA
- Flathead Lake Biological Station, University of Montana, Polson, Montana USA (present address)
- Department of Zoology and Physiology, University of Wyoming, Laramie, Wyoming USA
| | - C. Alex Buerkle
- Department of Botany, University of Wyoming, Laramie, Wyoming USA
- Program in Ecology, University of Wyoming, Laramie, Wyoming USA
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Morphometric Analyses of Leaf Shapes in Four Sympatric Mediterranean Oaks and Hybrids in the Algerian Kabylie Forest. FORESTS 2022. [DOI: 10.3390/f13040508] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
(1) Background: local morphological variation can provide useful information to clarify the role of hybridization in Mediterranean oaks. Accordingly, we have characterized putative hybrids and oak species coexisting in a highly diversified oak forest in Algeria with four native oak species (Quercus suber L., Q. ilex L., Q. canariensis Willd., and Q. afares Pomel). (2) Methods: sixteen plots, including 89 trees from the four native species and their putative hybrids were sampled. Leaves were scanned and their geometric morphometry analyzed by using 11 landmarks on the right side on their abaxial surface. Variation within and among species, and the relationship among oak species and their hybrids were analyzed, utilizing an ANOVA and a canonical analysis using morphoJ software. (3) Results: using the geometric morphometry analysis, we observed that Q. afares shape is intermediate between Q. suber and Q. canariensis, being Q. ilex very different from the others, and that there is no overlap among them. Putative hybrids are morphologically close to Q. afares and, to a lesser extent, to Q. suber and, finally, to Q. ilex and Q. canariensis. (4) Conclusions: the study opens the field for future molecular characterization of hybrids, and for determining their role in terms of adaptation to actual and predicted future climatic conditions. The morphological proximity of hybrids to Q. afares demonstrate this species advantage in the area of study and its importance for the future evolution of the species in the Mediterranean.
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Tamaki I, Obora T, Ohsawa T, Matsumoto A, Saito Y, Ide Y. Different population size change and migration histories created genetic diversity of three oaks in Tokai region, central Japan. JOURNAL OF PLANT RESEARCH 2021; 134:933-946. [PMID: 34155542 DOI: 10.1007/s10265-021-01323-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 06/14/2021] [Indexed: 06/13/2023]
Abstract
To understand genetic diversity in focal species, it is important to consider the possibility of speciation with gene flow, especially in species with porous genomes such as oaks. We studied genetic diversity and structure in three oaks, Quercus mongolica var. mongolicoides (QM), Q. mongolica var. crispula (QC) and Q. serrata (QS), growing in the Tokai region, central Japan. QM is semi-endemic to the region while the others are common taxa. We also conducted demographic modeling to infer their population size change and migration histories using an approximate Bayesian computation (ABC) approach. The three taxa showed distinct genetic structures but there was genetic admixture among the taxa, especially between QM and QC. ABC analysis of population size change revealed that the population size of QM was stable during and after the last glacial period, while QC and QS showed population expansion after the last glacial maximum. ABC analysis of population divergence and migration revealed that continuous gene flow between QM and QC after their divergence was supported, while between QM and QS, and between QC and QS, secondary contact after sufficient isolation was supported. These historical migration patterns among the three taxa indicate that QM and QC are currently in the early stage or gray zone of speciation, whereas speciation of the other two taxon pairs is considered to have almost been established. Observed gene flow patterns and strength between QM and QC, and between QM and QS, were explained by both flowering patterns and historical distributions, but those between QC and QS were not.
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Affiliation(s)
- Ichiro Tamaki
- Gifu Academy of Forest Science and Culture, 88 Sodai, Mino, Gifu, 501-3714, Japan.
| | - Tomohiro Obora
- Gifu Academy of Forest Science and Culture, 88 Sodai, Mino, Gifu, 501-3714, Japan
| | - Takafumi Ohsawa
- Ministry of the Environment, 1-2-2 Kasumigaseki, Chiyoda-ku, Tokyo, 100-8975, Japan
| | - Asako Matsumoto
- Forestry and Forest Products Research Institute, 1 Matsunosato, Tsukuba, Ibaraki, 305-8687, Japan
| | - Yoko Saito
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1, Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan
| | - Yuji Ide
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1, Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan
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Eusemann P, Liesebach H. Small-scale genetic structure and mating patterns in an extensive sessile oak forest ( Quercus petraea (Matt.) Liebl.). Ecol Evol 2021; 11:7796-7809. [PMID: 34188852 PMCID: PMC8216985 DOI: 10.1002/ece3.7613] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 03/01/2021] [Accepted: 04/08/2021] [Indexed: 11/20/2022] Open
Abstract
Oaks (Quercus) are major components of temperate forest ecosystems in the Northern Hemisphere where they form intermediate or climax communities. Sessile oak (Quercus petraea) forests represent the climax vegetation in eastern Germany and western Poland. Here, sessile oak forms pure stands or occurs intermixed with Scots Pine (Pinus sylvestris). A large body of research is available on gene flow, reproduction dynamics, and genetic structure in fragmented landscapes and mixed populations. At the same time, our knowledge regarding large, contiguous, and monospecific populations is considerably less well developed. Our study is an attempt to further develop our understanding of the reproduction ecology of sessile oak as an ecologically and economically important forest tree by analyzing mating patterns and genetic structure within adult trees and seedlings originating from one or two reproduction events in an extensive, naturally regenerating sessile oak forest. We detected positive spatial genetic structure up to 30 meters between adult trees and up to 40 meters between seedlings. Seed dispersal distances averaged 8.4 meters. Pollen dispersal distances averaged 22.6 meters. In both cases, the largest proportion of the dispersal occurred over short distances. Dispersal over longer distances was more common for pollen but also appeared regularly for seeds. The reproductive success of individual trees was highly skewed. Only 41 percent of all adult trees produced any offspring while the majority did not participate in reproduction. Among those trees that contributed to the analyzed seedling sample, 80 percent contributed 1-3 gametes. Only 20 percent of all parent trees contributed four or more gametes. However, these relatively few most fertile trees contributed 51 percent of all gametes within the seedling sample. Vitality and growth differed significantly between reproducing and nonreproducing adult trees with reproducing trees being more vital and vigorous than nonreproducing individuals. Our study demonstrates that extensive, apparently homogenous oak forests are far from uniform on the genetic level. On the contrary, they form highly complex mosaics of remarkably small local neighborhoods. This counterbalances the levelling effect of long-distance dispersal and may increase the species' adaptive potential. Incorporating these dynamics in the management, conservation, and restoration of oak forests can support the conservation of forest genetic diversity and assist those forests in coping with environmental change.
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Genetic, Morphological, and Environmental Differentiation of an Arid-Adapted Oak with a Disjunct Distribution. FORESTS 2021. [DOI: 10.3390/f12040465] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The patterns of genetic and morphological diversity of a widespread species can be influenced by environmental heterogeneity and the degree of connectivity across its geographic distribution. Here, we studied Quercus havardii Rydb., a uniquely adapted desert oak endemic to the Southwest region of the United States, using genetic, morphometric, and environmental datasets over various geographic scales to quantify differentiation and understand forces influencing population divergence. First, we quantified variation by analyzing 10 eastern and 13 western populations from the disjunct distribution of Q. havardii using 11 microsatellite loci, 17 morphological variables, and 19 bioclimatic variables. We then used regressions to examine local and regional correlations of climate with genetic variation. We found strong genetic, morphological and environmental differences corresponding with the large-scale disjunction of populations. Additionally, western populations had higher genetic diversity and lower relatedness than eastern populations. Levels of genetic variation in the eastern populations were found to be primarily associated with precipitation seasonality, while levels of genetic variation in western populations were associated with lower daily temperature fluctuations and higher winter precipitation. Finally, we found little to no observed environmental niche overlap between regions. Our results suggest that eastern and western populations likely represent two distinct taxonomic entities, each associated with a unique set of climatic variables potentially influencing local patterns of diversity.
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Kremer A, Hipp AL. Oaks: an evolutionary success story. THE NEW PHYTOLOGIST 2020; 226:987-1011. [PMID: 31630400 PMCID: PMC7166131 DOI: 10.1111/nph.16274] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2019] [Accepted: 09/13/2019] [Indexed: 05/10/2023]
Abstract
The genus Quercus is among the most widespread and species-rich tree genera in the northern hemisphere. The extraordinary species diversity in America and Asia together with the continuous continental distribution of a limited number of European species raise questions about how macro- and microevolutionary processes made the genus Quercus an evolutionary success. Synthesizing conclusions reached during the past three decades by complementary approaches in phylogenetics, phylogeography, genomics, ecology, paleobotany, population biology and quantitative genetics, this review aims to illuminate evolutionary processes leading to the radiation and expansion of oaks. From opposing scales of time and geography, we converge on four overarching explanations of evolutionary success in oaks: accumulation of large reservoirs of diversity within populations and species; ability for rapid migration contributing to ecological priority effects on lineage diversification; high rates of evolutionary divergence within clades combined with convergent solutions to ecological problems across clades; and propensity for hybridization, contributing to adaptive introgression and facilitating migration. Finally, we explore potential future research avenues, emphasizing the integration of microevolutionary and macroevolutionary perspectives.
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Affiliation(s)
- Antoine Kremer
- BIOGECO, INRA, Université de Bordeaux, 69 Route
d'Arcachon, 33612 Cestas, France
| | - Andrew L. Hipp
- The Morton Arboretum, Lisle IL 60532-1293, USA
- The Field Museum, Chicago IL 60605, USA
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Leroy T, Louvet JM, Lalanne C, Le Provost G, Labadie K, Aury JM, Delzon S, Plomion C, Kremer A. Adaptive introgression as a driver of local adaptation to climate in European white oaks. THE NEW PHYTOLOGIST 2020; 226:1171-1182. [PMID: 31394003 PMCID: PMC7166132 DOI: 10.1111/nph.16095] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Accepted: 07/31/2019] [Indexed: 05/10/2023]
Abstract
Latitudinal and elevational gradients provide valuable experimental settings for studies of the potential impact of global warming on forest tree species. The availability of long-term phenological surveys in common garden experiments for traits associated with climate, such as bud flushing for sessile oaks (Quercus petraea), provide an ideal opportunity to investigate this impact. We sequenced 18 sessile oak populations and used available sequencing data for three other closely related European white oak species (Quercus pyrenaica, Quercus pubescens, and Quercus robur) to explore the evolutionary processes responsible for shaping the genetic variation across latitudinal and elevational gradients in extant sessile oaks. We used phenotypic surveys in common garden experiments and climatic data for the population of origin to perform genome-wide scans for population differentiation and genotype-environment and genotype-phenotype associations. The inferred historical relationships between Q. petraea populations suggest that interspecific gene flow occurred between Q. robur and Q. petraea populations from cooler or wetter areas. A genome-wide scan of differentiation between Q. petraea populations identified single nucleotide polymorphisms (SNPs) displaying strong interspecific relative divergence between these two species. These SNPs followed genetic clines along climatic or phenotypic gradients, providing further support for the likely contribution of introgression to the adaptive divergence of Q. petraea populations. Overall, the results indicate that outliers and associated SNPs are Q. robur ancestry-informative. We discuss the results of this study in the framework of the postglacial colonization scenario, in which introgression and diversifying selection have been proposed as essential drivers of Q. petraea microevolution.
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Affiliation(s)
- Thibault Leroy
- BIOGECO, INRA, Université de Bordeaux, 69 Route d'Arcachon, 33612 Cestas, France
- ISEM, Univ. Montpellier, CNRS, IRD, EPHE, Place Eugène Bataillon, 34095 Montpellier, France
| | - Jean-Marc Louvet
- BIOGECO, INRA, Université de Bordeaux, 69 Route d'Arcachon, 33612 Cestas, France
| | - Céline Lalanne
- BIOGECO, INRA, Université de Bordeaux, 69 Route d'Arcachon, 33612 Cestas, France
| | - Grégoire Le Provost
- BIOGECO, INRA, Université de Bordeaux, 69 Route d'Arcachon, 33612 Cestas, France
| | - Karine Labadie
- Genoscope, Institut de biologie François-Jacob, Commissariat à l'Energie Atomique (CEA), Université Paris-Saclay, Evry, France
| | - Jean-Marc Aury
- Genoscope, Institut de biologie François-Jacob, Commissariat à l'Energie Atomique (CEA), Université Paris-Saclay, Evry, France
| | - Sylvain Delzon
- BIOGECO, INRA, Université de Bordeaux, 69 Route d'Arcachon, 33612 Cestas, France
| | - Christophe Plomion
- BIOGECO, INRA, Université de Bordeaux, 69 Route d'Arcachon, 33612 Cestas, France
| | - Antoine Kremer
- BIOGECO, INRA, Université de Bordeaux, 69 Route d'Arcachon, 33612 Cestas, France
- Corresponding author : Antoine Kremer, Phone number: +33(0)5 57 12 38 32,
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Reutimann O, Gugerli F, Rellstab C. A species-discriminatory single-nucleotide polymorphism set reveals maintenance of species integrity in hybridizing European white oaks (Quercus spp.) despite high levels of admixture. ANNALS OF BOTANY 2020; 125:663-676. [PMID: 31912148 PMCID: PMC7102958 DOI: 10.1093/aob/mcaa001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 01/04/2020] [Indexed: 06/10/2023]
Abstract
BACKGROUND AND AIMS Hybridization and introgression play an important role in the evolution and diversification of plants. To assess the degree of past and current hybridization, the level of genetic admixture in populations needs to be investigated. Ongoing hybridization and blurred species separation have made it challenging to assign European white oak taxa based on leaf morphology and/or genetic markers and to assess the level of admixture. Therefore, there is a need for powerful markers that differentiate between taxa. Here, we established a condensed set of single-nucleotide polymorphism (SNP) markers to reliably differentiate between the three most common oak species in temperate European forests (Quercus robur, Q. petraea, Q. pubescens) and to assess the degree of admixture in a large set of selected Swiss populations. METHODS A training set of 194 presumably pure reference samples from Switzerland and Europe was used to assign 633 test individuals with two different approaches (population genetic-based/Bayesian vs. assumption-free/discriminative classifier) using 58 selected SNPs from coding regions. Admixture was calculated at the individual and population level with the Shannon diversity index based on individual assignment probabilities. KEY RESULTS Depending on the approach, 97.5-100 % of training individuals were assigned correctly, and additional analyses showed that the established SNP set could be further reduced while maintaining its discriminatory power. The two assignment approaches showed high overlap (99 %) in assigning training individuals and slightly less overlap in test individuals (84 %). Levels of admixture varied widely among populations. Mixed stands of Q. petraea and Q. pubescens revealed much higher degrees of admixture than mixed stands of the other two taxon pairs, accentuating high levels of gene flow between these two taxa in Switzerland. CONCLUSIONS Our set of SNPs warrants reliable taxon discrimination with great potential for further applications. We show that the three European white oak taxa have largely retained their species integrity in Switzerland despite high levels of admixture.
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Affiliation(s)
| | - Felix Gugerli
- Swiss Federal Research Institute WSL, Birmensdorf, Switzerland
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Vitasse Y, Bottero A, Cailleret M, Bigler C, Fonti P, Gessler A, Lévesque M, Rohner B, Weber P, Rigling A, Wohlgemuth T. Contrasting resistance and resilience to extreme drought and late spring frost in five major European tree species. GLOBAL CHANGE BIOLOGY 2019; 25:3781-3792. [PMID: 31436853 DOI: 10.1111/gcb.14803] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 07/04/2019] [Accepted: 08/01/2019] [Indexed: 05/23/2023]
Abstract
Extreme climate events (ECEs) such as severe droughts, heat waves, and late spring frosts are rare but exert a paramount role in shaping tree species distributions. The frequency of such ECEs is expected to increase with climate warming, threatening the sustainability of temperate forests. Here, we analyzed 2,844 tree-ring width series of five dominant European tree species from 104 Swiss sites ranging from 400 to 2,200 m a.s.l. for the period 1930-2016. We found that (a) the broadleaved oak and beech are sensitive to late frosts that strongly reduce current year growth; however, tree growth is highly resilient and fully recovers within 2 years; (b) radial growth of the conifers larch and spruce is strongly and enduringly reduced by spring droughts-these species are the least resistant and resilient to droughts; (c) oak, silver fir, and to a lower extent beech, show higher resistance and resilience to spring droughts and seem therefore better adapted to the future climate. Our results allow a robust comparison of the tree growth responses to drought and spring frost across large climatic gradients and provide striking evidence that the growth of some of the most abundant and economically important European tree species will be increasingly limited by climate warming. These results could serve for supporting species selection to maintain the sustainability of forest ecosystem services under the expected increase in ECEs.
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Affiliation(s)
- Yann Vitasse
- WSL Swiss Federal Institute for Forest, Snow and Landscape Research, Birmensdorf, Switzerland
- SwissForestLab, Birmensdorf, Switzerland
| | - Alessandra Bottero
- WSL Swiss Federal Institute for Forest, Snow and Landscape Research, Birmensdorf, Switzerland
- SwissForestLab, Birmensdorf, Switzerland
| | - Maxime Cailleret
- WSL Swiss Federal Institute for Forest, Snow and Landscape Research, Birmensdorf, Switzerland
- SwissForestLab, Birmensdorf, Switzerland
- UMR RECOVER, Aix Marseille Univ, IRSTEA, Aix-en-Provence, France
| | - Christof Bigler
- SwissForestLab, Birmensdorf, Switzerland
- Forest Ecology, Department of Environmental Systems Science, ETH Zurich, Zurich, Switzerland
| | - Patrick Fonti
- WSL Swiss Federal Institute for Forest, Snow and Landscape Research, Birmensdorf, Switzerland
- SwissForestLab, Birmensdorf, Switzerland
| | - Arthur Gessler
- WSL Swiss Federal Institute for Forest, Snow and Landscape Research, Birmensdorf, Switzerland
- SwissForestLab, Birmensdorf, Switzerland
- Institute of Terrestrial Ecology, ETH Zürich, Zürich, Switzerland
| | - Mathieu Lévesque
- SwissForestLab, Birmensdorf, Switzerland
- Forest Ecology, Department of Environmental Systems Science, ETH Zurich, Zurich, Switzerland
| | - Brigitte Rohner
- WSL Swiss Federal Institute for Forest, Snow and Landscape Research, Birmensdorf, Switzerland
- SwissForestLab, Birmensdorf, Switzerland
| | - Pascale Weber
- WSL Swiss Federal Institute for Forest, Snow and Landscape Research, Birmensdorf, Switzerland
| | - Andreas Rigling
- WSL Swiss Federal Institute for Forest, Snow and Landscape Research, Birmensdorf, Switzerland
- SwissForestLab, Birmensdorf, Switzerland
- Institute of Terrestrial Ecology, ETH Zürich, Zürich, Switzerland
| | - Thomas Wohlgemuth
- WSL Swiss Federal Institute for Forest, Snow and Landscape Research, Birmensdorf, Switzerland
- SwissForestLab, Birmensdorf, Switzerland
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Castillo-Mendoza E, Salinas-Sánchez D, Valencia-Cuevas L, Zamilpa A, Tovar-Sánchez E. Natural hybridisation among Quercus glabrescens, Q. rugosa and Q. obtusata (Fagaceae): Microsatellites and secondary metabolites markers. PLANT BIOLOGY (STUTTGART, GERMANY) 2019; 21:110-121. [PMID: 30117248 DOI: 10.1111/plb.12899] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 08/12/2018] [Indexed: 06/08/2023]
Abstract
Natural hybridisation has significant ecological, genetic and evolutionary consequences altering morphological and chemical characters of individuals. Quercus glabrescens, Q. rugosa and Q. obtusata are white oak species well separated by their morphological characters when they occur in allopatry in Mexican temperate forests. However, in sympatry, individuals with atypical morphology have been observed, suggesting hybridisation events. In this study, we determined, with microsatellites and secondary metabolites, if interspecific gene flow occurs when these three oak species coexist in sympatry. In total, 180 individuals belonging to seven populations [three allopatric (one for each parental species) and four sympatric sites] were analysed. Allopatric populations represent well-defined genetic groups and the sympatric populations showed genetic evidence of hybridisation between Q. glabrescens × Q. rugosa and Q. glabrescens × Q. obtusata. The hybridisation percentage varied between sites and combination of involved species. We registered the presence of unique flavonoid compounds for Q. glabrescens (caffeic acid and flavonol 2), Q. rugosa (flavonol 5) and Q. obtusata (flavonol 1). Three compounds (quercetin rhamnoside, flavonol 3 and alkyl coumarate) were expressed in all taxa. Finally, the hybrid genotypes identified in this study (Q. glabrescens × Q. rugosa and Q. glabrescens × Q. obtusata) showed specific chemical profiles, resulting from a combination of those of their parental species. These results show that hybridisation events between these oak species alter chemical expression of secondary metabolites, creating a mosaic of resources and conditions that provide the substrate for different combinations of foliar-associated species such as herbivores, endophytic fungi or epiphyte plants.
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Affiliation(s)
- E Castillo-Mendoza
- Posgrado en Ciencias Biológicas, Universidad Nacional Autónoma de México, CdMx, México
- Laboratorio de Marcadores Moleculares, Centro de Investigación en Biodiversidad y Conservación, Universidad Autónoma del Estado de Morelos, Cuernavaca, Morelos, México
| | - D Salinas-Sánchez
- Laboratorio de Fitoquímica, Centro de Investigación en Biodiversidad y Conservación, Universidad Autónoma del Estado de Morelos, Cuernavaca, Morelos, México
| | - L Valencia-Cuevas
- Laboratorio de Marcadores Moleculares, Centro de Investigación en Biodiversidad y Conservación, Universidad Autónoma del Estado de Morelos, Cuernavaca, Morelos, México
| | - A Zamilpa
- Centro de Investigación Biomédica del Sur (CIBIS-IMSS), Xochitepec, Morelos, México
| | - E Tovar-Sánchez
- Laboratorio de Marcadores Moleculares, Centro de Investigación en Biodiversidad y Conservación, Universidad Autónoma del Estado de Morelos, Cuernavaca, Morelos, México
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Cannon CH, Scher CL. Exploring the potential of gametic reconstruction of parental genotypes by F 1 hybrids as a bridge for rapid introgression. Genome 2017; 60:713-719. [PMID: 28732173 DOI: 10.1139/gen-2016-0181] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Interspecific hybridization and genetic introgression are commonly observed in natural populations of many species, especially trees. Among oaks, gene flow between closely related species has been well documented. And yet, hybridization does not lead to a "melting pot", i.e., the homogenization of phenotypic traits. Here, we explore how the combination of several common reproductive and genomic traits could create an avenue for interspecific gene flow that partially explains this apparent paradox. During meiosis, F1 hybrids will produce approximately (½)n "reconstructed" parental gametes, where n equals the number of chromosomes. Crossing over would introduce a small amount of introgressive material. The resulting parental-type gametophytes would probably possess a similar fertilization advantage as conspecific pollen. The resulting "backcross" would actually be the genetic equivalent of a conspecific out-cross, with a small amount of heterospecific DNA captured through crossing over. Even with detailed genomic analysis, the resulting offspring would not appear to be a backcross. This avenue for rapid introgression between species through the F1 hybrid will be viable for organisms that meet certain conditions: low base chromosome number, conserved genomic structure and size, production of billions of gametes/gametophytes during each reproductive event, and conspecific fertilization advantage.
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Affiliation(s)
- Charles H Cannon
- The Center for Tree Science, The Morton Arboretum, Lisle, IL 60532, USA.,The Center for Tree Science, The Morton Arboretum, Lisle, IL 60532, USA
| | - C Lane Scher
- The Center for Tree Science, The Morton Arboretum, Lisle, IL 60532, USA.,The Center for Tree Science, The Morton Arboretum, Lisle, IL 60532, USA
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13
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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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14
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Ortego J, Gugger PF, Sork VL. Impacts of human-induced environmental disturbances on hybridization between two ecologically differentiated Californian oak species. THE NEW PHYTOLOGIST 2017; 213:942-955. [PMID: 27621132 DOI: 10.1111/nph.14182] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Accepted: 08/04/2016] [Indexed: 05/15/2023]
Abstract
Natural hybridization, which can be involved in local adaptation and in speciation processes, has been linked to different sources of anthropogenic disturbance. Here, we use genotypic data to study range-wide patterns of genetic admixture between the serpentine-soil specialist leather oak (Quercus durata) and the widespread Californian scrub oak (Quercus berberidifolia). First, we estimated hybridization rates and the direction of gene flow. Second, we tested the hypothesis that genetic admixture increases with different sources of environmental disturbance, namely anthropogenic destruction of natural habitats and wildfire frequency estimated from long-term records of fire occurrence. Our analyses indicate considerable rates of hybridization (> 25%), asymmetric gene flow from Q. durata into Q. berberidifolia, and a higher occurrence of hybrids in areas where both species live in close parapatry. In accordance with the environmental disturbance hypothesis, we found that genetic admixture increases with wildfire frequency, but we did not find a significant effect of other sources of human-induced habitat alteration (urbanization, land clearing for agriculture) or a suite of ecological factors (climate, elevation, soil type). Our findings highlight that wildfires constitute an important source of environmental disturbance, promoting hybridization between two ecologically well-differentiated native species.
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Affiliation(s)
- Joaquín Ortego
- Department of Integrative Ecology, Estación Biológica de Doñana, EBD-CSIC, Avda. Américo Vespucio s/n, E-41092, Seville, Spain
| | - Paul F Gugger
- Appalachian Laboratory, University of Maryland Center for Environmental Science, 301 Braddock Road, Frostburg, MD, 21532, USA
| | - Victoria L Sork
- Department of Ecology and Evolutionary Biology, University of California, Box 957239, Los Angeles, CA, 90095, USA
- Institute of the Environment and Sustainability, University of California, Box 951496, Los Angeles, CA, 90095-1496, USA
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15
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Adaptive Variation and Introgression of a CONSTANS-Like Gene in North American Red Oaks. FORESTS 2016. [DOI: 10.3390/f8010003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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16
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Rellstab C, Zoller S, Walthert L, Lesur I, Pluess AR, Graf R, Bodénès C, Sperisen C, Kremer A, Gugerli F. Signatures of local adaptation in candidate genes of oaks (Quercusspp.) with respect to present and future climatic conditions. Mol Ecol 2016; 25:5907-5924. [DOI: 10.1111/mec.13889] [Citation(s) in RCA: 92] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Revised: 08/22/2016] [Accepted: 10/03/2016] [Indexed: 01/08/2023]
Affiliation(s)
- Christian Rellstab
- WSL Swiss Federal Research Institute; Zürcherstrasse 111 8903 Birmensdorf Switzerland
| | - Stefan Zoller
- Genetic Diversity Centre; ETH Zürich; Universitätstrasse 16 8092 Zürich Switzerland
| | - Lorenz Walthert
- WSL Swiss Federal Research Institute; Zürcherstrasse 111 8903 Birmensdorf Switzerland
| | - Isabelle Lesur
- UMR1202 BIOGECO; INRA; 33610 Cestas France
- UMR1202 BIOGECO; Université de Bordeaux; 33610 Talence France
- Helix Venture; 26 rue Eugène Scribe 33700 Mérignac France
| | - Andrea R. Pluess
- WSL Swiss Federal Research Institute; Zürcherstrasse 111 8903 Birmensdorf Switzerland
- Institute of Terrestrial Ecosystems; ETH Zürich; Universitätstrasse 16 8092 Zürich Switzerland
| | - René Graf
- WSL Swiss Federal Research Institute; Zürcherstrasse 111 8903 Birmensdorf Switzerland
| | - Catherine Bodénès
- UMR1202 BIOGECO; INRA; 33610 Cestas France
- UMR1202 BIOGECO; Université de Bordeaux; 33610 Talence France
| | - Christoph Sperisen
- WSL Swiss Federal Research Institute; Zürcherstrasse 111 8903 Birmensdorf Switzerland
| | - Antoine Kremer
- UMR1202 BIOGECO; INRA; 33610 Cestas France
- UMR1202 BIOGECO; Université de Bordeaux; 33610 Talence France
| | - Felix Gugerli
- WSL Swiss Federal Research Institute; Zürcherstrasse 111 8903 Birmensdorf Switzerland
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17
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Gompert Z, Buerkle CA. What, if anything, are hybrids: enduring truths and challenges associated with population structure and gene flow. Evol Appl 2016; 9:909-23. [PMID: 27468308 PMCID: PMC4947152 DOI: 10.1111/eva.12380] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Accepted: 02/27/2016] [Indexed: 01/17/2023] Open
Abstract
Hybridization is a potent evolutionary process that can affect the origin, maintenance, and loss of biodiversity. Because of its ecological and evolutionary consequences, an understanding of hybridization is important for basic and applied sciences, including conservation biology and agriculture. Herein, we review and discuss ideas that are relevant to the recognition of hybrids and hybridization. We supplement this discussion with simulations. The ideas we present have a long history, particularly in botany, and clarifying them should have practical consequences for managing hybridization and gene flow in plants. One of our primary goals is to illustrate what we can and cannot infer about hybrids and hybridization from molecular data; in other words, we ask when genetic analyses commonly used to study hybridization might mislead us about the history or nature of gene flow and selection. We focus on patterns of variation when hybridization is recent and populations are polymorphic, which are particularly informative for applied issues, such as contemporary hybridization following recent ecological change. We show that hybridization is not a singular process, but instead a collection of related processes with variable outcomes and consequences. Thus, it will often be inappropriate to generalize about the threats or benefits of hybridization from individual studies, and at minimum, it will be important to avoid categorical thinking about what hybridization and hybrids are. We recommend potential sampling and analytical approaches that should help us confront these complexities of hybridization.
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18
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Beatty GE, Montgomery WI, Spaans F, Tosh DG, Provan J. Pure species in a continuum of genetic and morphological variation: sympatric oaks at the edge of their range. ANNALS OF BOTANY 2016; 117:541-9. [PMID: 26929202 PMCID: PMC4817430 DOI: 10.1093/aob/mcw002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Accepted: 11/17/2015] [Indexed: 05/25/2023]
Abstract
BACKGROUND AND AIMS Studies on oaks (Quercus spp.) have often been hampered by taxonomic confusion, a situation further compounded by the occurrence of extensive interspecific hybridization. In the present study, a combination of genetic and morphological analyses was used to examine sympatric populations of Q. petraea and Q. robur at the north-western edge of their ranges in Northern Ireland, since it had previously been suggested that hybridization could facilitate the apparent rapid, long-distance dispersal of oaks following the glaciations. METHODS Samples were collected from 24 sites across Northern Ireland that had been previously designated as ancient or semi-natural woodland. Genotypes were obtained from a total of 950 trees using 12 nuclear microsatellite loci, and admixture coefficients were calculated based on a Bayesian clustering approach. Individuals were also classified as Q. petraea,Q. robur or hybrids based on two objective morphometric characters shown previously to delineate pure individuals effectively. Genetically 'pure' individuals of both species, as defined by the Bayesian clustering, were also genotyped for five chloroplast microsatellites. KEY RESULTS Genetic and morphological analyses both indicated the presence of pure individuals of both species, as well as a continuum of intermediates. There was a good agreement between the molecular and morphological classification, with a generally clear separation between pure individuals. CONCLUSIONS Despite millennia of hybridization and introgression, genetically and morphologically pure individuals of both Q. petraea and Q. robur can be found at the edge of their range, where both species occur sympatrically. The high proportion of individuals exhibiting introgression compared with previous studies may reflect the historical role of hybridization in facilitating dispersal following the glaciations. This is further supported by the significantly higher chloroplast diversity in Q. robur compared with Q. petraea.
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Affiliation(s)
- Gemma E Beatty
- School of Biological Sciences, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7BL, UK, Quercus, School of Biological Sciences, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7BL, UK and Institute for Global Food Security, Queen's University Belfast
| | - W Ian Montgomery
- School of Biological Sciences, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7BL, UK, Quercus, School of Biological Sciences, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7BL, UK and Institute for Global Food Security, Queen's University Belfast
| | - Florentine Spaans
- School of Biological Sciences, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7BL, UK, Quercus, School of Biological Sciences, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7BL, UK and
| | - David G Tosh
- School of Biological Sciences, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7BL, UK, Quercus, School of Biological Sciences, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7BL, UK and
| | - Jim Provan
- School of Biological Sciences, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7BL, UK, Quercus, School of Biological Sciences, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7BL, UK and Institute for Global Food Security, Queen's University Belfast
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19
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Bodénès C, Chancerel E, Ehrenmann F, Kremer A, Plomion C. High-density linkage mapping and distribution of segregation distortion regions in the oak genome. DNA Res 2016; 23:115-24. [PMID: 27013549 PMCID: PMC4833419 DOI: 10.1093/dnares/dsw001] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 01/05/2016] [Indexed: 11/14/2022] Open
Abstract
We developed the densest single-nucleotide polymorphism (SNP)-based linkage genetic map to date for the genus Quercus An 8k gene-based SNP array was used to genotype more than 1,000 full-sibs from two intraspecific and two interspecific full-sib families of Quercus petraea and Quercus robur A high degree of collinearity was observed between the eight parental maps of the two species. A composite map was then established with 4,261 SNP markers spanning 742 cM over the 12 linkage groups (LGs) of the oak genome. Nine genomic regions from six LGs displayed highly significant distortions of segregation. Two main hypotheses concerning the mechanisms underlying segregation distortion are discussed: genetic load vs. reproductive barriers. Our findings suggest a predominance of pre-zygotic to post-zygotic barriers.
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Affiliation(s)
- Catherine Bodénès
- INRA, UMR1202 BIOGECO, F-33610 Cestas, France Université de Bordeaux, UMR1202 BIOGECO, F-33610 Talence, France
| | - Emilie Chancerel
- INRA, UMR1202 BIOGECO, F-33610 Cestas, France Université de Bordeaux, UMR1202 BIOGECO, F-33610 Talence, France
| | - François Ehrenmann
- INRA, UMR1202 BIOGECO, F-33610 Cestas, France Université de Bordeaux, UMR1202 BIOGECO, F-33610 Talence, France
| | - Antoine Kremer
- INRA, UMR1202 BIOGECO, F-33610 Cestas, France Université de Bordeaux, UMR1202 BIOGECO, F-33610 Talence, France
| | - Christophe Plomion
- INRA, UMR1202 BIOGECO, F-33610 Cestas, France Université de Bordeaux, UMR1202 BIOGECO, F-33610 Talence, France
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20
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A linkage disequilibrium perspective on the genetic mosaic of speciation in two hybridizing Mediterranean white oaks. Heredity (Edinb) 2014; 114:373-86. [PMID: 25515016 DOI: 10.1038/hdy.2014.113] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Revised: 10/11/2014] [Accepted: 11/12/2014] [Indexed: 01/09/2023] Open
Abstract
We analyzed the genetic mosaic of speciation in two hybridizing Mediterranean white oaks from the Iberian Peninsula (Quercus faginea Lamb. and Quercus pyrenaica Willd.). The two species show ecological divergence in flowering phenology, leaf morphology and composition, and in their basic or acidic soil preferences. Ninety expressed sequence tag-simple sequence repeats (EST-SSRs) and eight nuclear SSRs were genotyped in 96 trees from each species. Genotyping was designed in two steps. First, we used 69 markers evenly distributed over the 12 linkage groups (LGs) of the oak linkage map to confirm the species genetic identity of the sampled genotypes, and searched for differentiation outliers. Then, we genotyped 29 additional markers from the chromosome bins containing the outliers and repeated the multilocus scans. We found one or two additional outliers within four saturated bins, thus confirming that outliers are organized into clusters. Linkage disequilibrium (LD) was extensive; even for loosely linked and for independent markers. Consequently, score tests for association between two-marker haplotypes and the 'species trait' showed a broad genomic divergence, although substantial variation across the genome and within LGs was also observed. We discuss the influence of several confounding effects on neutrality tests and review the evolutionary processes leading to extensive LD. Finally, we examine how LD analyses within regions that contain outlier clusters and quantitative trait loci can help to identify regions of divergence and/or genomic hitchhiking in the light of predictions from ecological speciation theory.
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21
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Lagache L, Klein EK, Ducousso A, Petit RJ. Distinct male reproductive strategies in two closely related oak species. Mol Ecol 2014; 23:4331-43. [DOI: 10.1111/mec.12766] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Revised: 03/12/2014] [Accepted: 04/08/2014] [Indexed: 11/30/2022]
Affiliation(s)
- Lélia Lagache
- INRA; UMR 1202 Biogeco; F-33610 Cestas France
- Univ. Bordeaux; UMR1202 Biogeco; F-33400 Talence France
| | - Etienne K. Klein
- Biostatistique et Processus Spatiaux (BioSP); INRA; UR546; F-84914 Avignon France
| | - Alexis Ducousso
- INRA; UMR 1202 Biogeco; F-33610 Cestas France
- Univ. Bordeaux; UMR1202 Biogeco; F-33400 Talence France
| | - Rémy J. Petit
- INRA; UMR 1202 Biogeco; F-33610 Cestas France
- Univ. Bordeaux; UMR1202 Biogeco; F-33400 Talence France
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22
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Lindtke D, Gompert Z, Lexer C, Buerkle CA. Unexpected ancestry ofPopulusseedlings from a hybrid zone implies a large role for postzygotic selection in the maintenance of species. Mol Ecol 2014; 23:4316-30. [DOI: 10.1111/mec.12759] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Revised: 03/15/2014] [Accepted: 04/08/2014] [Indexed: 01/17/2023]
Affiliation(s)
- Dorothea Lindtke
- Department of Botany; University of Wyoming; Laramie WY 82071 USA
- Unit of Ecology and Evolution; Department of Biology; University of Fribourg; 1700 Fribourg Switzerland
| | - Zachariah Gompert
- Department of Biology and Ecology Center; Utah State University; Logan UT 84322 USA
| | - Christian Lexer
- Unit of Ecology and Evolution; Department of Biology; University of Fribourg; 1700 Fribourg Switzerland
| | - C. Alex Buerkle
- Department of Botany; University of Wyoming; Laramie WY 82071 USA
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23
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Lind-Riehl JF, Sullivan AR, Gailing O. Evidence for selection on a CONSTANS-like gene between two red oak species. ANNALS OF BOTANY 2014; 113:967-75. [PMID: 24615344 PMCID: PMC3997637 DOI: 10.1093/aob/mcu019] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Accepted: 01/27/2014] [Indexed: 05/25/2023]
Abstract
BACKGROUND AND AIMS Hybridizing species such as oaks may provide a model to study the role of selection in speciation with gene flow. Discrete species' identities and different adaptations are maintained among closely related oak species despite recurrent gene flow. This is probably due to ecologically mediated selection at a few key genes or genomic regions. Neutrality tests can be applied to identify so-called outlier loci, which demonstrate locus-specific signatures of divergent selection and are candidate genes for further study. METHODS Thirty-six genic microsatellite markers, some with putative functions in flowering time and drought tolerance, and eight non-genic microsatellite markers were screened in two population pairs (n = 160) of the interfertile species Quercus rubra and Q. ellipsoidalis, which are characterized by contrasting adaptations to drought. Putative outliers were then tested in additional population pairs from two different geographic regions (n = 159) to support further their potential role in adaptive divergence. KEY RESULTS A marker located in the coding sequence of a putative CONSTANS-like (COL) gene was repeatedly identified as under strong divergent selection across all three geographically disjunct population pairs. COL genes are involved in the photoperiodic control of growth and development and are implicated in the regulation of flowering time. CONCLUSIONS The location of the polymorphism in the Quercus COL gene and given the potential role of COL genes in adaptive divergence and reproductive isolation makes this a promising candidate speciation gene. Further investigation of the phenological characteristics of both species and flowering time pathway genes is suggested in order to elucidate the importance of phenology genes for the maintenance of species integrity. Next-generation sequencing in multiple population pairs in combination with high-density genetic linkage maps could reveal the genome-wide distribution of outlier genes and their potential role in reproductive isolation between these species.
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Affiliation(s)
| | | | - Oliver Gailing
- Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931, USA
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24
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Roe AD, MacQuarrie CJK, Gros-Louis MC, Simpson JD, Lamarche J, Beardmore T, Thompson SL, Tanguay P, Isabel N. Fitness dynamics within a poplar hybrid zone: I. Prezygotic and postzygotic barriers impacting a native poplar hybrid stand. Ecol Evol 2014; 4:1629-47. [PMID: 24967081 PMCID: PMC4063464 DOI: 10.1002/ece3.1029] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Revised: 12/20/2013] [Accepted: 12/31/2013] [Indexed: 01/30/2023] Open
Abstract
Hybridization and introgression are pervasive evolutionary phenomena that provide insight into the selective forces that maintain species boundaries, permit gene flow, and control the direction of evolutionary change. Poplar trees (Populus L.) are well known for their ability to form viable hybrids and maintain their distinct species boundaries despite this interspecific gene flow. We sought to quantify the hybridization dynamics and postzygotic fitness within a hybrid stand of balsam poplar (Populus balsamifera L.), eastern cottonwood (P. deltoides Marsh.), and their natural hybrids to gain insight into the barriers maintaining this stable hybrid zone. We observed asymmetrical hybrid formation with P. deltoides acting as the seed parent, but with subsequent introgression biased toward P. balsamifera. Native hybrids expressed fitness traits intermediate to the parental species and were not universally unfit. That said, native hybrid seedlings were absent from the seedling population, which may indicate additional selective pressures controlling their recruitment. It is imperative that we understand the selective forces maintaining this native hybrid zone in order to quantify the impact of exotic poplar hybrids on this native system.
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Affiliation(s)
- Amanda D Roe
- Natural Resources Canada, Canadian Forest Service, Laurentian Forestry CentreQuébec, Québec, Canada
- Natural Resources Canada, Canadian Forestry Centre, Great Lakes Forestry CentreSault Ste. Marie, Ontario, Canada
| | - Chris J K MacQuarrie
- Natural Resources Canada, Canadian Forestry Centre, Great Lakes Forestry CentreSault Ste. Marie, Ontario, Canada
| | - Marie-Claude Gros-Louis
- Natural Resources Canada, Canadian Forest Service, Laurentian Forestry CentreQuébec, Québec, Canada
| | - J Dale Simpson
- Natural Resources Canada, Canadian Forest Service, Atlantic Forestry CentreFredericton, New Brunswick, Canada
| | - Josyanne Lamarche
- Natural Resources Canada, Canadian Forest Service, Laurentian Forestry CentreQuébec, Québec, Canada
| | - Tannis Beardmore
- Natural Resources Canada, Canadian Forest Service, Atlantic Forestry CentreFredericton, New Brunswick, Canada
| | - Stacey L Thompson
- Natural Resources Canada, Canadian Forest Service, Laurentian Forestry CentreQuébec, Québec, Canada
- Umeå University, Ecology and Environmental Sciences, Umeå Plant Science CentreUmeå, Sweden
| | - Philippe Tanguay
- Natural Resources Canada, Canadian Forest Service, Laurentian Forestry CentreQuébec, Québec, Canada
| | - Nathalie Isabel
- Natural Resources Canada, Canadian Forest Service, Laurentian Forestry CentreQuébec, Québec, Canada
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25
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Demeter Z, Kanalas P, Máthé C, Cseke K, Szőllősi E, M-Hamvas M, Jámbrik K, Kiss Z, Mészáros I. Osmotic stress responses of individual white oak (Quercus section, Quercus subgenus) genotypes cultured in vitro. JOURNAL OF PLANT PHYSIOLOGY 2014; 171:16-24. [PMID: 24331415 DOI: 10.1016/j.jplph.2013.09.013] [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: 06/25/2013] [Revised: 09/11/2013] [Accepted: 09/22/2013] [Indexed: 06/03/2023]
Abstract
White oaks (Quercus section, Quercus subgenus) are widely distributed in Europe. Quercus petraea (sessile oak), an economically important species is predicted to be affected by climate change. Q. pubescens (pubescent oak) and Q. virgiliana (Italian pubescent oak) are economically less important, drought tolerant species. Frequent hybridization of white oaks was observed and currently the introgression of Q. pubescens and Q. virgiliana in non-mediterranean regions of Europe has been reported. Our goal was to use tissue cultures established from individual trees of the above taxa and their putative hybrids, all present in the forest stand of Síkfőkút LTER Research Area (NE Hungary) as simple experimental model systems for studying drought/osmotic stress tolerance. Tissue cultures are more suitable models for such studies, than seedlings, because they are genetically identical to the parent plants. Polyethylene glycol (PEG6000) treatments were used for this purpose. The identification of taxa was based on leaf morphological traits and microsatellite analysis and showed that Q. petraea is genetically distinct to all other taxa examined. We established six callus lines of Quercus. As expected, in Q. petraea cultures PEG6000 induced severe loss of fresh weight and the ability to recover after removal of the osmoticum, which was not characteristic for Q. pubescens and Q. virgiliana. Putative hybrids exhibited an intermediate response to osmotic stress. Activity gels showed the increase of single-strand preferring (SSP) nuclease and no significant change of guaiacol-peroxidase activities in drought-sensitive genotypes/cultures and no significant increase of SSP nuclease activities accompanied with increases of guaiacol-peroxidase activities in drought-tolerant ones. This indicates that drought/osmotic stress tolerance is associated to increased capacity of scavenging reactive oxygen species and hence less susceptibility to DNA damage. Our results confirm that tissue cultures of oak are suitable model systems for studying drought/osmotic stress responses.
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Affiliation(s)
- Zita Demeter
- University of Debrecen, Faculty of Science and Technology, Department of Botany, PO Box 14, H-4010 Debrecen, Hungary
| | - Péter Kanalas
- University of Debrecen, Faculty of Science and Technology, Department of Botany, PO Box 14, H-4010 Debrecen, Hungary
| | - Csaba Máthé
- University of Debrecen, Faculty of Science and Technology, Department of Botany, PO Box 14, H-4010 Debrecen, Hungary.
| | - Klára Cseke
- Hungarian Forest Research Institute, PO Box 30/A, H-9600 Sárvár, Hungary
| | - Erzsébet Szőllősi
- University of Debrecen, Faculty of Science and Technology, Department of Botany, PO Box 14, H-4010 Debrecen, Hungary
| | - Márta M-Hamvas
- University of Debrecen, Faculty of Science and Technology, Department of Botany, PO Box 14, H-4010 Debrecen, Hungary
| | - Katalin Jámbrik
- University of Debrecen, Faculty of Science and Technology, Department of Botany, PO Box 14, H-4010 Debrecen, Hungary
| | - Zoltán Kiss
- University of Debrecen, Faculty of Science and Technology, Department of Botany, PO Box 14, H-4010 Debrecen, Hungary
| | - Ilona Mészáros
- University of Debrecen, Faculty of Science and Technology, Department of Botany, PO Box 14, H-4010 Debrecen, Hungary.
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Gerber S, Chadœuf J, Gugerli F, Lascoux M, Buiteveld J, Cottrell J, Dounavi A, Fineschi S, Forrest LL, Fogelqvist J, Goicoechea PG, Jensen JS, Salvini D, Vendramin GG, Kremer A. High rates of gene flow by pollen and seed in oak populations across Europe. PLoS One 2014; 9:e85130. [PMID: 24454802 PMCID: PMC3890301 DOI: 10.1371/journal.pone.0085130] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Accepted: 11/10/2013] [Indexed: 11/18/2022] Open
Abstract
Gene flow is a key factor in the evolution of species, influencing effective population size, hybridisation and local adaptation. We analysed local gene flow in eight stands of white oak (mostly Quercus petraea and Q. robur, but also Q. pubescens and Q. faginea) distributed across Europe. Adult trees within a given area in each stand were exhaustively sampled (range [239, 754], mean 423), mapped, and acorns were collected ([17,147], 51) from several mother trees ([3], [47], 23). Seedlings ([65,387], 178) were harvested and geo-referenced in six of the eight stands. Genetic information was obtained from screening distinct molecular markers spread across the genome, genotyping each tree, acorn or seedling. All samples were thus genotyped at 5–8 nuclear microsatellite loci. Fathers/parents were assigned to acorns and seedlings using likelihood methods. Mating success of male and female parents, pollen and seed dispersal curves, and also hybridisation rates were estimated in each stand and compared on a continental scale. On average, the percentage of the wind-borne pollen from outside the stand was 60%, with large variation among stands (21–88%). Mean seed immigration into the stand was 40%, a high value for oaks that are generally considered to have limited seed dispersal. However, this estimate varied greatly among stands (20–66%). Gene flow was mostly intraspecific, with large variation, as some trees and stands showed particularly high rates of hybridisation. Our results show that mating success was unevenly distributed among trees. The high levels of gene flow suggest that geographically remote oak stands are unlikely to be genetically isolated, questioning the static definition of gene reserves and seed stands.
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Affiliation(s)
- Sophie Gerber
- BIOGECO, UMR1202, INRA, Cestas, France ; BIOGECO, UMR1202, University of Bordeaux, Talence, France
| | | | - Felix Gugerli
- Biodiversity and Conservation Biology, WSL Swiss Federal Research Institute, Birmensdorf, Switzerland
| | - Martin Lascoux
- Department of Ecology and Genetics, EBC, Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | | | - Joan Cottrell
- Forest Research, Northern Research Station, Roslin, Midlothian, Scotland, United Kingdom
| | - Aikaterini Dounavi
- Biodiversity and Conservation Biology, WSL Swiss Federal Research Institute, Birmensdorf, Switzerland
| | - Silvia Fineschi
- Institute for Plant Protection, CNR, Sesto Fiorentino (Firenze), Italy
| | - Laura L Forrest
- Forest Research, Northern Research Station, Roslin, Midlothian, Scotland, United Kingdom
| | - Johan Fogelqvist
- Department of Ecology and Genetics, EBC, Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | | | | | - Daniela Salvini
- Institute for Plant Protection, CNR, Sesto Fiorentino (Firenze), Italy ; Forest & Landscape, University of Copenhagen, Copenhagen, Denmark
| | - Giovanni G Vendramin
- Institute of Biosciences and Bioresources, CNR, Sesto Fiorentino (Firenze), Italy
| | - Antoine Kremer
- BIOGECO, UMR1202, INRA, Cestas, France ; BIOGECO, UMR1202, University of Bordeaux, Talence, France
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27
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Chybicki IJ, Burczyk J. Seeing the forest through the trees: comprehensive inference on individual mating patterns in a mixed stand of Quercus robur and Q. petraea. ANNALS OF BOTANY 2013; 112:561-74. [PMID: 23788747 PMCID: PMC3718219 DOI: 10.1093/aob/mct131] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
BACKGROUND AND AIMS Sexual reproduction is one of the most important moments in a life cycle, determining the genetic composition of individual offspring. Controlled pollination experiments often show high variation in the mating system at the individual level, suggesting a persistence of individual variation in natural populations. Individual variation in mating patterns may have significant adaptive implications for a population and for the entire species. Nevertheless, field data rarely address individual differences in mating patterns, focusing rather on averages. This study aimed to quantify individual variation in the different components of mating patterns. METHODS Microsatellite data were used from 421 adult trees and 1911 seeds, structured in 72 half-sib families collected in a single mixed stand of Quercus robur and Q. petraea in northern Poland. Using a Bayesian approach, mating patterns were investigated, taking into account pollen dispersal, male fecundity, possible hybridization and heterogeneity in immigrant pollen pools. KEY RESULTS Pollen dispersal followed a heavy-tailed distribution (283 m on average). In spite of high pollen mobility, immigrant pollen pools showed strong genetic structuring among mothers. At the individual level, immigrant pollen pools showed highly variable divergence rates, revealing that sources of immigrant pollen can vary greatly among particular trees. Within the stand, the distribution of male fecundity appeared highly skewed, with a small number of dominant males, resulting in a ratio of census to effective density of pollen donors of 5·3. Male fecundity was not correlated with tree diameter but showed strong cline-like spatial variation. This pattern can be attributed to environmental variation. Quercus petraea revealed a greater preference (74 %) towards intraspecific mating than Q. robur (36 %), although mating preferences varied among trees. CONCLUSIONS Mating patterns can reveal great variation among individuals, even within a single even-age stand. The results show that trees can mate assortatively, with little respect for spatial proximity. Such selective mating may be a result of variable combining compatibility among trees due to genetic and/or environmental factors.
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Affiliation(s)
- Igor J Chybicki
- Department of Genetics, Institute of Experimental Biology, Kazimierz Wielki University, 85064 Bydgoszcz, Poland.
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28
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Lagache L, Leger JB, Daudin JJ, Petit RJ, Vacher C. Putting the biological species concept to the test: using mating networks to delimit species. PLoS One 2013; 8:e68267. [PMID: 23818990 PMCID: PMC3688613 DOI: 10.1371/journal.pone.0068267] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Accepted: 05/28/2013] [Indexed: 11/19/2022] Open
Abstract
Although interfertility is the key criterion upon which Mayr's biological species concept is based, it has never been applied directly to delimit species under natural conditions. Our study fills this gap. We used the interfertility criterion to delimit two closely related oak species in a forest stand by analyzing the network of natural mating events between individuals. The results reveal two groups of interfertile individuals connected by only few mating events. These two groups were largely congruent with those determined using other criteria (morphological similarity, genotypic similarity and individual relatedness). Our study, therefore, shows that the analysis of mating networks is an effective method to delimit species based on the interfertility criterion, provided that adequate network data can be assembled. Our study also shows that although species boundaries are highly congruent across methods of species delimitation, they are not exactly the same. Most of the differences stem from assignment of individuals to an intermediate category. The discrepancies between methods may reflect a biological reality. Indeed, the interfertility criterion is an environment-dependant criterion as species abundances typically affect rates of hybridization under natural conditions. Thus, the methods of species delimitation based on the interfertility criterion are expected to give results slightly different from those based on environment-independent criteria (such as the genotypic similarity criteria). However, whatever the criterion chosen, the challenge we face when delimiting species is to summarize continuous but non-uniform variations in biological diversity. The grade of membership model that we use in this study appears as an appropriate tool.
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Affiliation(s)
- Lélia Lagache
- INRA, UMR1202 BIOGECO, Cestas, France
- Univ. Bordeaux, BIOGECO, UMR 1202, Talence, France
| | - Jean-Benoist Leger
- INRA, UMR 518 MIA, Paris, France
- AgroParisTech, UMR 518 MIA, Paris, France
| | | | - Rémy J. Petit
- INRA, UMR1202 BIOGECO, Cestas, France
- Univ. Bordeaux, BIOGECO, UMR 1202, Talence, France
| | - Corinne Vacher
- INRA, UMR1202 BIOGECO, Cestas, France
- Univ. Bordeaux, BIOGECO, UMR 1202, Talence, France
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29
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Ruhsam M, Hollingsworth PM, Ennos RA. Patterns of mating, generation of diversity, and fitness of offspring in a Geum hybrid swarm. Evolution 2013; 67:2728-40. [PMID: 24033179 DOI: 10.1111/evo.12147] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2012] [Accepted: 04/16/2013] [Indexed: 12/01/2022]
Abstract
To understand the evolutionary consequences of hybridization between the outcrossing plant Geum rivale (Rosaceae) and the selfer Geum urbanum, we tested the predictions of two simple models that assume either (A) low or (B) high pollen fitness in hybrids. Model A predicts only four genotypic classes (G. rivale, G. rivale backcross [BC(R)], F1, and Geum urbanum) and asymmetric introgression from inbreeding to outbreeding species. Model B predicts additional genotypic classes and potential generation of novel inbreeding lines in the hybrid swarm. Amplified fragment length polymorphism (AFLP) analysis of adults revealed only the four genotypes predicted by model A. However, microsatellite analysis of parent-progeny arrays demonstrated production of selfed offspring by F1 and BC(R) maternal parents and contribution of these genotypes to outcross pollen pools, as predicted by model B. Moreover, AFLP and morphological analysis showed that the offspring generation comprised genotypes and phenotypes covering the entire spectrum of variation between the two parental species, in line with model B. A common garden experiment indicated no systematic reduction in fitness of offspring derived from hybrid parents. The genetic structure of the adults in the Geum hybrid swarm cannot be explained by restricted mating patterns but may result from ecological selection acting on a diverse offspring population.
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Affiliation(s)
- Markus Ruhsam
- University of Edinburgh, Institute of Evolutionary Biology, Ashworth Laboratories, Edinburgh, EH3 9JT, United Kingdom; Royal Botanic Garden Edinburgh, Edinburgh, EH3 5LR, United Kingdom.
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30
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Goicoechea PG, Petit RJ, Kremer A. Detecting the footprints of divergent selection in oaks with linked markers. Heredity (Edinb) 2012; 109:361-71. [PMID: 22990311 PMCID: PMC3499841 DOI: 10.1038/hdy.2012.51] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2011] [Revised: 06/13/2012] [Accepted: 07/17/2012] [Indexed: 12/14/2022] Open
Abstract
Genome scans are increasingly used to study ecological speciation, providing a useful genome-wide perspective on divergent selection in the presence of gene flow. Here, we compare current approaches to detect footprints of divergent selection in closely related species. We analyzed 192 individuals from two interfertile European temperate oak species using 30 nuclear microsatellites from eight linkage groups. These markers present little intraspecific differentiation and can be used in combination to assign individual genotypes to species. We first show that different outlier detection tests give somewhat different results, possibly due to model constraints. Second, using linkage information for these markers, we further characterize the signature of divergent selection in the presence of gene flow. In particular, we show that recombination estimates for regions with outlier markers are lower than those for a control region, in line with a prediction from ecological speciation theory. Most importantly, we show that analyses at the haplotype level can distinguish between truly divergent (bi-directional) selection and positive selection in one of the two species, offering a new and improved method for characterizing the speciation process.
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Affiliation(s)
- P G Goicoechea
- Department of Biotechnology, NEIKER-Tecnalia, Vitoria-Gasteiz, Spain.
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31
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Lagache L, Klein EK, Guichoux E, Petit RJ. Fine-scale environmental control of hybridization in oaks. Mol Ecol 2012; 22:423-36. [PMID: 23173566 DOI: 10.1111/mec.12121] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2012] [Revised: 08/31/2012] [Accepted: 09/11/2012] [Indexed: 12/14/2022]
Abstract
Natural hybridization is attracting much interest in modern speciation and conservation biology studies, but the underlying mechanisms remain poorly understood. In particular, it is unclear why environmental changes often increase hybridization rates. To study this question, we surveyed mating events in a mixed oak stand and developed a spatially explicit individual-based hybridization model. This model, where hybridization is frequency-dependent, pollen is nonlimiting and which allows immigrant pollen to compete with local pollen, takes into account species-specific pollen dispersal and sexual barriers to hybridization. The consequences of pollen limitation on hybridization were studied using another simple model. The results indicate that environmental changes could increase hybridization rates through two distinct mechanisms. First, by disrupting the spatial organization of communities, they should decrease the proportion of conspecific pollen available for mating, thus increasing hybridization rates. Second, by decreasing the density of conspecifics, they should increase pollen limitation and thus hybridization rates, as a consequence of chance pollination predominating over deterministic pollen competition. Altogether, our results point to a need for considering hybridization events at the appropriate level of organization and provide new insights into why hybridization rates generally increase in disturbed environments.
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Affiliation(s)
- Lélia Lagache
- INRA, UMR1202 Biogeco, F- 33610, Cestas, France; UMR1202 Biogeco, Univ. Bordeaux, F-33400, Talence, France
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32
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Abadie P, Roussel G, Dencausse B, Bonnet C, Bertocchi E, Louvet JM, Kremer A, Garnier-Géré P. Strength, diversity and plasticity of postmating reproductive barriers between two hybridizing oak species (Quercus robur L. and Quercus petraea (Matt) Liebl.). J Evol Biol 2011; 25:157-73. [PMID: 22092648 DOI: 10.1111/j.1420-9101.2011.02414.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Very little is known about the nature and strength of reproductive isolation (RI) in Quercus species, despite extensive research on the estimation and evolutionary significance of hybridization rates. We characterized postmating pre- and postzygotic RI between two hybridizing oak species, Quercus robur and Quercus petraea, using a large set of controlled crosses between different genotypes. Various traits potentially associated with reproductive barriers were quantified at several life history stages, from pollen-pistil interactions to seed set and progeny fitness-related traits. Results indicate strong intrinsic postmating prezygotic barriers, with significant barriers also at the postzygotic level, but relatively weaker extrinsic barriers on early hybrid fitness measures assessed in controlled conditions. Using general linear modelling of common garden data with clonal replicates, we showed that most traits exhibited important genotypic differences, as well as different levels of sensitivity to micro-environmental heterogeneity. These new findings suggest a large potential genetic diversity and plasticity of reproductive barriers and are confronted with hybridization evidence in these oak species.
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Affiliation(s)
- P Abadie
- INRA, UMR 1202 BIOGECO, 69 route d'Arcachon, F-33612 Cestas, France
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33
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Jahner JP, Shapiro AM, Forister ML. Drivers of hybridization in a 66-generation record of Colias butterflies. Evolution 2011; 66:818-830. [PMID: 22380442 DOI: 10.1111/j.1558-5646.2011.01481.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Hybridization significantly affects the ecology and evolution of numerous plant and animal lineages. Most studies have focused on endogenous drivers of hybridization and neglected variation in exogenous factors, such as seasonal weather patterns. In this study, we take advantage of a unique dataset consisting of records of hybridization between the butterflies Colias eurytheme and C. eriphyle (Pieridae) for 66 generations (22 years) to investigate the importance of seasonal weather on the production and survival of hybrid offspring. Important seasonal weather variables for each parental species and hybrid offspring were determined using model averaging, and these weather variables, along with butterfly abundances, were analyzed using path analysis. The most important drivers of hybridization were the abundance of C. eriphyle, summer minimum temperature, and spring maximum temperature. In contrast, the abundance of C. eurytheme and weather variables prior to the current flight season were relatively unimportant for variation in hybrid abundance. Parental abundances were mostly driven by weather variables prior to the flight season possibly because these variables affect host plant quality. Our results suggest that exogenous, climatic factors can influence hybridization in natural systems, and that these factors can act both directly on hybrid abundance and indirectly through the population dynamics of parental species.
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Affiliation(s)
- Joshua P Jahner
- Program in Ecology, Evolution, and Conservation Biology, Department of Biology, University of Nevada, Reno, Nevada 89557 E-mail: for Population Biology, University of California, Davis, California 95616
| | - Arthur M Shapiro
- Program in Ecology, Evolution, and Conservation Biology, Department of Biology, University of Nevada, Reno, Nevada 89557 E-mail: for Population Biology, University of California, Davis, California 95616
| | - Matthew L Forister
- Program in Ecology, Evolution, and Conservation Biology, Department of Biology, University of Nevada, Reno, Nevada 89557 E-mail: for Population Biology, University of California, Davis, California 95616
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