1
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Stoeckel S, Becheler R, Bocharova E, Barloy D. GenAPoPop 1.0: A user-friendly software to analyse genetic diversity and structure from partially clonal and selfed autopolyploid organisms. Mol Ecol Resour 2024; 24:e13886. [PMID: 37902131 DOI: 10.1111/1755-0998.13886] [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: 11/23/2022] [Revised: 10/05/2023] [Accepted: 10/16/2023] [Indexed: 10/31/2023]
Abstract
Autopolyploidy is quite common in most clades of eukaryotes. The emergence of sequence-based genotyping methods with individual and marker tags now enables confident allele dosage, overcoming the main obstacle to the democratization of the population genetic approaches when studying ecology and evolution of autopolyploid populations and species. Reproductive modes, including clonality, selfing and allogamy, have deep consequences on the ecology and evolution of population and species. Analysing genetic diversity and its dynamics over generations is one efficient way to infer the relative importance of clonality, selfing and allogamy in populations. GenAPoPop is a user-friendly solution to compute the specific corpus of population genetic indices, including indices about genotypic diversity, needed to analyse partially clonal, selfed and allogamous polysomic populations genotyped with confident allele dosage. It also easily provides the posterior probabilities of quantitative reproductive modes in autopolyploid populations genotyped at two-time steps and a graphical representation of the minimum spanning trees of the genetic distances between polyploid individuals, facilitating the interpretation of the genetic coancestry between individuals in hierarchically structured populations. GenAPoPop complements the previously existing solutions, including SPAGEDI and POLYGENE, to use genotypings to study the ecology and evolution of autopolyploid populations. It was specially developed with a simple graphical interface and workflow, and comes with a simulator to facilitate practical courses and teaching of population genetics for autopolyploid populations.
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Affiliation(s)
- Solenn Stoeckel
- IGEPP, INRAE, Institut Agro, Université de Rennes, Le Rheu, France
- DECOD (Ecosystem Dynamics and Sustainability), Institut Agro, IFREMER, INRAE, Rennes, France
| | - Ronan Becheler
- IGEPP, INRAE, Institut Agro, Université de Rennes, Le Rheu, France
- DECOD (Ecosystem Dynamics and Sustainability), Institut Agro, IFREMER, INRAE, Rennes, France
| | - Ekaterina Bocharova
- Evolutionary Developmental Biology laboratory, Koltzov Institute of Developmental Biology of Russian Academy of Sciences (IDB RAS), Moscow, Russia
| | - Dominique Barloy
- DECOD (Ecosystem Dynamics and Sustainability), Institut Agro, IFREMER, INRAE, Rennes, France
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2
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Blischak PD, Sajan M, Barker MS, Gutenkunst RN. Demographic history inference and the polyploid continuum. Genetics 2023; 224:iyad107. [PMID: 37279657 PMCID: PMC10411560 DOI: 10.1093/genetics/iyad107] [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: 04/17/2023] [Revised: 04/17/2023] [Accepted: 05/18/2023] [Indexed: 06/08/2023] Open
Abstract
Polyploidy is an important generator of evolutionary novelty across diverse groups in the Tree of Life, including many crops. However, the impact of whole-genome duplication depends on the mode of formation: doubling within a single lineage (autopolyploidy) versus doubling after hybridization between two different lineages (allopolyploidy). Researchers have historically treated these two scenarios as completely separate cases based on patterns of chromosome pairing, but these cases represent ideals on a continuum of chromosomal interactions among duplicated genomes. Understanding the history of polyploid species thus demands quantitative inferences of demographic history and rates of exchange between subgenomes. To meet this need, we developed diffusion models for genetic variation in polyploids with subgenomes that cannot be bioinformatically separated and with potentially variable inheritance patterns, implementing them in the dadi software. We validated our models using forward SLiM simulations and found that our inference approach is able to accurately infer evolutionary parameters (timing, bottleneck size) involved with the formation of auto- and allotetraploids, as well as exchange rates in segmental allotetraploids. We then applied our models to empirical data for allotetraploid shepherd's purse (Capsella bursa-pastoris), finding evidence for allelic exchange between the subgenomes. Taken together, our model provides a foundation for demographic modeling in polyploids using diffusion equations, which will help increase our understanding of the impact of demography and selection in polyploid lineages.
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Affiliation(s)
- Paul D Blischak
- Department of Ecology & Evolutionary Biology, University of Arizona, Tucson, AZ 85721, USA
- Department of Molecular & Cellular Biology, University of Arizona, Tucson, AZ 85721, USA
- Bayer Crop Science, Chesterfield, MO 63017, USA
| | - Mathews Sajan
- Department of Molecular & Cellular Biology, University of Arizona, Tucson, AZ 85721, USA
| | - Michael S Barker
- Department of Ecology & Evolutionary Biology, University of Arizona, Tucson, AZ 85721, USA
| | - Ryan N Gutenkunst
- Department of Molecular & Cellular Biology, University of Arizona, Tucson, AZ 85721, USA
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3
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Schedler M, Reutemann AV, Hojsgaard DH, Zilli AL, Brugnoli EA, Galdeano F, Acuña CA, Honfi AI, Martínez EJ. Alternative Evolutionary Pathways in Paspalum Involving Allotetraploidy, Sexuality, and Varied Mating Systems. Genes (Basel) 2023; 14:1137. [PMID: 37372317 DOI: 10.3390/genes14061137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 05/17/2023] [Accepted: 05/22/2023] [Indexed: 06/29/2023] Open
Abstract
The genetic systems of Paspalum species have not been extensively studied. We analyzed the ploidy, reproductive mode, mating system, and fertility of four Paspalum species-Paspalum durifolium, Paspalum ionanthum, Paspalum regnellii, and Paspalum urvillei. An analysis of 378 individuals from 20 populations of northeastern Argentina was conducted. All populations of the four Paspalum species were pure tetraploid and had a sexual and stable reproductive mode. However, some populations of P. durifolium and P. ionanthum showed low levels of apospory. Populations of P. durifolium and P. ionanthum had low seed sets under self-pollination but were fertile under open pollination, showing that self-incompatibility likely caused self-sterility. In contrast, populations of P. regnellii or P. urvillei showed no evidence of apospory, and seed sets in both self- and open pollination conditions were high, suggesting that they are self-compatible due to the absence of pollen-pistil molecular incompatibility mechanisms. The evolutionary origin of the four Paspalum species could explain these differences. This study supplies valuable insights into the genetic systems of Paspalum species, which could have implications for their conservation and management.
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Affiliation(s)
- Mara Schedler
- Instituto de Botánica del Nordeste (IBONE-UNNE-CONICET), Facultad de Ciencias Agrarias, Universidad Nacional del Nordeste (FCA-UNNE), Corrientes 3400, Corrientes, Argentina
| | - Anna Verena Reutemann
- Instituto de Botánica del Nordeste (IBONE-UNNE-CONICET), Facultad de Ciencias Agrarias, Universidad Nacional del Nordeste (FCA-UNNE), Corrientes 3400, Corrientes, Argentina
| | - Diego Hernán Hojsgaard
- Taxonomy & Evolutionary Biology, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), 06466 Gatersleben, Germany
| | - Alex Leonel Zilli
- Instituto de Botánica del Nordeste (IBONE-UNNE-CONICET), Facultad de Ciencias Agrarias, Universidad Nacional del Nordeste (FCA-UNNE), Corrientes 3400, Corrientes, Argentina
| | - Elsa Andrea Brugnoli
- Instituto de Botánica del Nordeste (IBONE-UNNE-CONICET), Facultad de Ciencias Agrarias, Universidad Nacional del Nordeste (FCA-UNNE), Corrientes 3400, Corrientes, Argentina
| | - Florencia Galdeano
- Instituto de Botánica del Nordeste (IBONE-UNNE-CONICET), Facultad de Ciencias Agrarias, Universidad Nacional del Nordeste (FCA-UNNE), Corrientes 3400, Corrientes, Argentina
| | - Carlos Alberto Acuña
- Instituto de Botánica del Nordeste (IBONE-UNNE-CONICET), Facultad de Ciencias Agrarias, Universidad Nacional del Nordeste (FCA-UNNE), Corrientes 3400, Corrientes, Argentina
| | - Ana Isabel Honfi
- Programa de Estudios Florísticos y Genética Vegetal, Instituto de Biología Subtropical (PEFyGV, IBS-UNaM-CONICET), Posadas 3300, Misiones, Argentina
| | - Eric Javier Martínez
- Instituto de Botánica del Nordeste (IBONE-UNNE-CONICET), Facultad de Ciencias Agrarias, Universidad Nacional del Nordeste (FCA-UNNE), Corrientes 3400, Corrientes, Argentina
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4
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Grossfurthner LP, Milano ER, Hohenlohe PA, Waits LP, Richardson BA. Population structure and hybridization under contemporary and future climates in a heteroploid foundational shrub species ( Artemisia tridentata). FRONTIERS IN PLANT SCIENCE 2023; 14:1155868. [PMID: 37284723 PMCID: PMC10239881 DOI: 10.3389/fpls.2023.1155868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 04/20/2023] [Indexed: 06/08/2023]
Abstract
Current and past climatic changes can shift plant climatic niches, which may cause spatial overlap or separation between related taxa. The former often leads to hybridization and introgression, which may generate novel variation and influence the adaptive capacity of plants. An additional mechanism facilitating adaptations to novel environments and an important evolutionary driver in plants is polyploidy as the result of whole genome duplication. Artemisia tridentata (big sagebrush) is a landscape-dominating foundational shrub in the western United States which occupies distinct ecological niches, exhibiting diploid and tetraploid cytotypes. Tetraploids have a large impact on the species' landscape dominance as they occupy a preponderance of the arid spectrum of A. tridentata range. Three distinct subspecies are recognized, which co-occur in ecotones - the transition zone between two or more distinct ecological niches - allowing for hybridization and introgression. Here we assess the genomic distinctiveness and extent of hybridization among subspecies at different ploidies under both contemporary and predicted future climates. We sampled five transects throughout the western United States where a subspecies overlap was predicted using subspecies-specific climate niche models. Along each transect, we sampled multiple plots representing the parental and the potential hybrid habitats. We performed reduced representation sequencing and processed the data using a ploidy-informed genotyping approach. Population genomic analyses revealed distinct diploid subspecies and at least two distinct tetraploid gene pools, indicating independent origins of the tetraploid populations. We detected low levels of hybridization (2.5%) between the diploid subspecies, while we found evidence for increased admixture between ploidy levels (18%), indicating hybridization has an important role in the formation of tetraploids. Our analyses highlight the importance of subspecies co-occurrence within these ecotones to maintain gene exchange and potential formation of tetraploid populations. Genomic confirmations of subspecies in the ecotones support the subspecies overlap predicted by the contemporary climate niche models. However, future mid-century projections of subspecies niches predict a substantial loss in range and subspecies overlap. Thus, reductions in hybridization potential could affect new recruitment of genetically variable tetraploids that are vital to this species' ecological role. Our results underscore the importance of ecotone conservation and restoration.
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Affiliation(s)
- Lukas P. Grossfurthner
- Bioinformatics and Computational Biology Graduate Program, University of Idaho, Moscow, ID, United States
- Department of Biological Sciences, University of Idaho, Moscow, ID, United States
| | - Elizabeth R. Milano
- Rocky Mountain Research Station, United States Department of Agriculture (USDA) Forest Service, Moscow, ID, United States
| | - Paul A. Hohenlohe
- Department of Biological Sciences, University of Idaho, Moscow, ID, United States
| | - Lisette P. Waits
- Department of Fish and Wildlife Sciences, University of Idaho, Moscow, ID, United States
| | - Bryce A. Richardson
- Rocky Mountain Research Station, United States Department of Agriculture (USDA) Forest Service, Moscow, ID, United States
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5
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Bomblies K. Learning to tango with four (or more): the molecular basis of adaptation to polyploid meiosis. PLANT REPRODUCTION 2023; 36:107-124. [PMID: 36149479 PMCID: PMC9957869 DOI: 10.1007/s00497-022-00448-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 08/10/2022] [Indexed: 05/29/2023]
Abstract
Polyploidy, which arises from genome duplication, has occurred throughout the history of eukaryotes, though it is especially common in plants. The resulting increased size, heterozygosity, and complexity of the genome can be an evolutionary opportunity, facilitating diversification, adaptation and the evolution of functional novelty. On the other hand, when they first arise, polyploids face a number of challenges, one of the biggest being the meiotic pairing, recombination and segregation of the suddenly more than two copies of each chromosome, which can limit their fertility. Both for developing polyploidy as a crop improvement tool (which holds great promise due to the high and lasting multi-stress resilience of polyploids), as well as for our basic understanding of meiosis and plant evolution, we need to know both the specific nature of the challenges polyploids face, as well as how they can be overcome in evolution. In recent years there has been a dramatic uptick in our understanding of the molecular basis of polyploid adaptations to meiotic challenges, and that is the focus of this review.
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Affiliation(s)
- Kirsten Bomblies
- Plant Evolutionary Genetics, Institute of Plant Molecular Biology, Department of Biology, ETH Zürich, Zurich, Switzerland.
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6
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Tong H, Deng H, Han Z. Genetic differentiation and genetic structure of mixed-ploidy Camellia hainanica populations. PeerJ 2023; 11:e14756. [PMID: 36852222 PMCID: PMC9961093 DOI: 10.7717/peerj.14756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Accepted: 12/27/2022] [Indexed: 02/24/2023] Open
Abstract
Camellia hainanica, which is common in China's Hainan Province, is an important woody olive tree species. Due to many years of geographic isolation, C. hainanica has not received the attention it deserves, which limits the exploitation of germplasm resources. Therefore, it is necessary to study population genetic characteristics for further utilization and conservation of C. hainanica. In this study, 96 individuals in six wild Camellia hainanica populations were used for ploidy analysis of the chromosome number, and the genetic diversity and population structure were investigated using 12 pairs of SSR primers. The results show complex ploidy differentiation in C. hainanica species. The ploidy of wild C. hainanica includes tetraploid, pentaploid, hexaploid, heptaploid, octoploid and decaploid species. Genetic analysis shows that genetic diversity and genetic differentiation among populations are low. Populations can be divided into two clusters based on their genetic structure, which matches their geographic location. Finally, to further maintain the genetic diversity of C. hainanica, ex-situ cultivation and in-situ management measures should be considered to protect it in the future.
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Affiliation(s)
- Hailang Tong
- Central South University of Forestry and Technology, The College of Forestry, Changsha, China,Central South University of Forestry and Technology, The Laboratory of Forestry Genetics, Changsha, China
| | - Hongda Deng
- Central South University of Forestry and Technology, The College of Forestry, Changsha, China,Central South University of Forestry and Technology, The Laboratory of Forestry Genetics, Changsha, China
| | - Zhiqiang Han
- Central South University of Forestry and Technology, The College of Forestry, Changsha, China,Central South University of Forestry and Technology, The Laboratory of Forestry Genetics, Changsha, China
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7
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Roux C, Vekemans X, Pannell J. Inferring the Demographic History and Inheritance Mode of Tetraploid Species Using ABC. Methods Mol Biol 2023; 2545:325-348. [PMID: 36720821 DOI: 10.1007/978-1-0716-2561-3_17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Genomic patterns of diversity and divergence are impacted by certain life history traits, reproductive systems, and demographic history. The latter is characterized by fluctuations in population sizes over time, as well as by temporal patterns of introgression. For a given organism, identifying a demographic history that deviates from the standard neutral model allows a better understanding of its evolution but also helps to reduce the risk of false positives when screening for molecular targets of natural selection. Tetraploid organisms and beyond have demographic histories that are complicated by the mode of polyploidization, the mode of inheritance, and different scenarios of gene flow between sub-genomes and diploid parental species. Here we provide guidelines for experimenters wishing to address these issues through a flexible statistical framework: approximate Bayesian computation (ABC). The emphasis is on the general philosophy of the approach to encourage future users to exploit the enormous flexibility of ABC beyond the limitations imposed by generalist data analysis pipelines.
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Affiliation(s)
- Camille Roux
- Univ. Lille, CNRS, UMR 8198 - Evo-Eco-Paleo, Lille, France.
| | | | - John Pannell
- Department of Ecology and Evolution, Biophore Building, University of Lausanne, Lausanne, Switzerland
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8
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Inference of Polyploid Origin and Inheritance Mode from Population Genomic Data. Methods Mol Biol 2023; 2545:279-295. [PMID: 36720819 DOI: 10.1007/978-1-0716-2561-3_15] [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: 02/02/2023]
Abstract
Whole-genome duplications yield varied chromosomal pairing patterns, ranging from strictly bivalent to multivalent, resulting in disomic and polysomic inheritance modes. In the bivalent case, homeologous chromosomes form pairs, where in a multivalent pattern all copies are homologous and are therefore free to pair and recombine. As sufficient sequencing data is more readily available than high-quality cytological assessments of meiotic behavior or population genetic assessment of allelic segregation, especially for non-model organisms, bioinformatics approaches to infer origins and inheritance modes of polyploids using short-read sequencing data are attractive. Here we describe two such approaches, where the first is based on distributions of allelic read depth at heterozygous sites within an individual, as the expectations of such distributions are different for disomic and polysomic inheritance modes. The second approach is more laborious and based on a phylogenetic assessment of partially phased haplotypes of a polyploid in comparison to the closest diploid relatives. We discuss the sources of deviations from expected inheritance patterns, advantages and pitfalls of both methods, effects of mating types on the performance of the methods, and possible future developments.
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9
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Bohutínská M, Vlček J, Monnahan P, Kolář F. Population Genomic Analysis of Diploid-Autopolyploid Species. Methods Mol Biol 2023; 2545:297-324. [PMID: 36720820 DOI: 10.1007/978-1-0716-2561-3_16] [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: 02/02/2023]
Abstract
This chapter outlines an empirical analysis of genome-wide single-nucleotide polymorphism (SNP) variation and its underlying drivers among multiple natural populations within a diploid-autopolyploid species. The aim is to reconstruct the genetic structure among natural populations of varying ploidy and infer footprints of selection in these populations, framed around specific questions that are typically encountered when analyzing a mixed-ploidy data set,e.g., addressing the relevance of natural whole-genome duplication for speciation and adaptation. We briefly review the options for the analysis of polyploid population genomic data involving variant calling, population structure, demographic history inference, and selection scanning approaches. Further, we provide suggestions for methods and associated software, possible caveats, and examples of their application to mixed-ploidy and autopolyploid data sets.
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Affiliation(s)
- Magdalena Bohutínská
- Department of Botany, Faculty of Science, Charles University, Prague, Czech Republic.,Institute of Botany of the Czech Academy of Sciences, Průhonice, Czech Republic
| | - Jakub Vlček
- Department of Botany, Faculty of Science, Charles University, Prague, Czech Republic
| | - Patrick Monnahan
- Department of Pediatrics, University of Minnesota, Minneapolis, MN, USA
| | - Filip Kolář
- Department of Botany, Faculty of Science, Charles University, Prague, Czech Republic. .,Institute of Botany of the Czech Academy of Sciences, Průhonice, Czech Republic.
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10
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Mairal M, García-Verdugo C, Le Roux JJ, Chau JH, van Vuuren BJ, Hui C, Münzbergová Z, Chown SL, Shaw JD. Multiple introductions, polyploidy and mixed reproductive strategies are linked to genetic diversity and structure in the most widespread invasive plant across Southern Ocean archipelagos. Mol Ecol 2023; 32:756-771. [PMID: 36478264 DOI: 10.1111/mec.16809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 11/30/2022] [Accepted: 12/01/2022] [Indexed: 12/12/2022]
Abstract
Biological invasions in remote areas that experience low human activity provide unique opportunities to elucidate processes responsible for invasion success. Here we study the most widespread invasive plant species across the isolated islands of the Southern Ocean, the annual bluegrass, Poa annua. To analyse geographical variation in genome size, genetic diversity and reproductive strategies, we sampled all major sub-Antarctic archipelagos in this region and generated microsatellite data for 470 individual plants representing 31 populations. We also estimated genome sizes for a subset of individuals using flow cytometry. Occasional events of island colonization are expected to result in high genetic structure among islands, overall low genetic diversity and increased self-fertilization, but we show that this is not the case for P. annua. Microsatellite data indicated low population genetic structure and lack of isolation by distance among the sub-Antarctic archipelagos we sampled, but high population structure within each archipelago. We identified high levels of genetic diversity, low clonality and low selfing rates in sub-Antarctic P. annua populations (contrary to rates typical of continental populations). In turn, estimates of selfing declined in populations as genetic diversity increased. Additionally, we found that most P. annua individuals are probably tetraploid and that only slight variation exists in genome size across the Southern Ocean. Our findings suggest multiple independent introductions of P. annua into the sub-Antarctic, which promoted the establishment of genetically diverse populations. Despite multiple introductions, the adoption of convergent reproductive strategies (outcrossing) happened independently in each major archipelago. The combination of polyploidy and a mixed reproductive strategy probably benefited P. annua in the Southern Ocean by increasing genetic diversity and its ability to cope with the novel environmental conditions.
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Affiliation(s)
- Mario Mairal
- Departamento de Biodiversidad, Ecología y Evolución, Universidad Complutense de Madrid, Madrid, Spain.,Department of Botany and Zoology, Stellenbosch University, Stellenbosch, South Africa
| | - Carlos García-Verdugo
- Departamento de Botánica, Facultad de Ciencias, Universidad de Granada, Granada, Spain.,Departamento de Biología, Universitat de les Illes Balears - Institut Mediterrani d'Estudis Avançats (CSIC-UIB), Mallorca, Spain
| | - Johannes J Le Roux
- Departamento de Biodiversidad, Ecología y Evolución, Universidad Complutense de Madrid, Madrid, Spain.,School of Natural Sciences, Macquarie University, New South Wales, Sydney, Australia
| | - John H Chau
- Department of Zoology, Centre for Ecological Genomics and Wildlife Conservation, University of Johannesburg, Auckland Park, South Africa
| | - Bettine Jansen van Vuuren
- Department of Zoology, Centre for Ecological Genomics and Wildlife Conservation, University of Johannesburg, Auckland Park, South Africa
| | - Cang Hui
- Department of Mathematical Sciences, Centre for Invasion Biology, Stellenbosch University, Stellenbosch, South Africa.,Biodiversity Informatics Unit, African Institute for Mathematical Sciences, Cape Town, South Africa
| | - Zuzana Münzbergová
- Faculty of Science, Department of Botany, Charles University, Prague, Czech Republic.,Institute of Botany, Czech Academy of Science, Průhonice, Czech Republic
| | - Steven L Chown
- Securing Antarctica's Environmental Future, School of Biological Sciences, Monash University, Melbourne, Victoria, Australia
| | - Justine D Shaw
- Securing Antarctica's Environmental Future, School of Biology and Environmental Sciences, Queensland University of Technology, Brisbane, Queensland, Australia.,Australian Antarctic Division, Tasmania, Kingston, Australia
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11
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Walisch TJ, Colling G, Hermant S, Matthies D. Molecular and quantitative genetic variation within and between populations of the declining grassland species
Saxifraga granulata. Ecol Evol 2022; 12:e9462. [DOI: 10.1002/ece3.9462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 09/06/2022] [Accepted: 10/04/2022] [Indexed: 11/21/2022] Open
Affiliation(s)
- Tania J. Walisch
- Musée National d'Histoire Naturelle Luxembourg City Luxembourg
- Department of Biology Philipps‐Universität Marburg Marburg Germany
| | - Guy Colling
- Musée National d'Histoire Naturelle Luxembourg City Luxembourg
| | - Sylvie Hermant
- Musée National d'Histoire Naturelle Luxembourg City Luxembourg
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12
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Clark LV, Mays W, Lipka AE, Sacks EJ. A population-level statistic for assessing Mendelian behavior of genotyping-by-sequencing data from highly duplicated genomes. BMC Bioinformatics 2022; 23:101. [PMID: 35317727 PMCID: PMC8939213 DOI: 10.1186/s12859-022-04635-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2021] [Accepted: 03/10/2022] [Indexed: 12/02/2022] Open
Abstract
Background Given the economic and environmental importance of allopolyploids and other species with highly duplicated genomes, there is a need for methods to distinguish paralogs, i.e. duplicate sequences within a genome, from Mendelian loci, i.e. single copy sequences that pair at meiosis. The ratio of observed to expected heterozygosity is an effective tool for filtering loci but requires genotyping to be performed first at a high computational cost, whereas counting the number of sequence tags detected per genotype is computationally quick but very ineffective in inbred or polyploid populations. Therefore, new methods are needed for filtering paralogs. Results We introduce a novel statistic, Hind/HE, that uses the probability that two reads sampled from a genotype will belong to different alleles, instead of observed heterozygosity. The expected value of Hind/HE is the same across all loci in a dataset, regardless of read depth or allele frequency. In contrast to methods based on observed heterozygosity, it can be estimated and used for filtering loci prior to genotype calling. In addition to filtering paralogs, it can be used to filter loci with null alleles or high overdispersion, and identify individuals with unexpected ploidy and hybrid status. We demonstrate that the statistic is useful at read depths as low as five to 10, well below the depth needed for accurate genotype calling in polyploid and outcrossing species. Conclusions Our methodology for estimating Hind/HE across loci and individuals, as well as determining reasonable thresholds for filtering loci, is implemented in polyRAD v1.6, available at https://github.com/lvclark/polyRAD. In large sequencing datasets, we anticipate that the ability to filter markers and identify problematic individuals prior to genotype calling will save researchers considerable computational time. Supplementary Information The online version contains supplementary material available at 10.1186/s12859-022-04635-9.
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Affiliation(s)
- Lindsay V Clark
- Roy J. Carver Biotechnology Center, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
| | - Wittney Mays
- Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.,Sandia National Laboratories, Livermore, CA, 94551, USA
| | - Alexander E Lipka
- Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Erik J Sacks
- Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
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13
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Salvado P, Aymerich Boixader P, Parera J, Vila Bonfill A, Martin M, Quélennec C, Lewin J, Delorme‐Hinoux V, Bertrand JAM. Little hope for the polyploid endemic Pyrenean Larkspur (
Delphinium montanum
): Evidences from population genomics and Ecological Niche Modeling. Ecol Evol 2022; 12:e8711. [PMID: 35342590 PMCID: PMC8932081 DOI: 10.1002/ece3.8711] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 02/11/2022] [Accepted: 02/18/2022] [Indexed: 11/17/2022] Open
Abstract
Species endemic to restricted geographical ranges represent a particular conservation issue, be it for their heritage interest. In a context of global change, this is particularly the case for plants which belong to high‐mountain ecosystems and, because of their ecological requirements, are doomed to survive or disappear on their “sky islands”. The Pyrenean Larkspur (Delphinium montanum, Ranunculaceae) is endemic to the Eastern part of the Pyrenees (France and Spain). It is now only observable at a dozen of localities and some populations show signs of decline, such as a recurrent lack of flowering. Implementing population genomics approach (e.g., RAD‐seq like) is particularly useful to understand genomic patterns of diversity and differentiation in order to provide recommendations in term of conservation. However, it remains challenging for species such as D. montanum that are autotetraploid with a large genome size (1C‐value >10 pg) as most methods currently available were developed for diploid species. A Bayesian framework able to call genotypes with uncertainty allowed us to assess genetic diversity and population structure in this system. Our results show evidence for inbreeding (mean GIS = 0.361) within all the populations and substantial population structure (mean GST = 0.403) at the metapopulation level. In addition to a lack of connectivity between populations, spatial projections of Ecological Niche Modeling (ENM) analyses under different climatic scenarios predict a dramatic decrease of suitable habitat for D. montanum in the future. Based on these results, we discuss the relevance and feasibility of different conservation measures.
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Affiliation(s)
- Pascaline Salvado
- Laboratoire Génome et Développement des Plantes (LGDP, UMR 5096 UPVD/CNRS) Université de Perpignan Via Domitia Perpignan France
| | | | - Josep Parera
- Fédération des Réserves Naturelles Catalanes Prades France
| | | | - Maria Martin
- Fédération des Réserves Naturelles Catalanes Prades France
| | | | | | - Valérie Delorme‐Hinoux
- Laboratoire Génome et Développement des Plantes (LGDP, UMR 5096 UPVD/CNRS) Université de Perpignan Via Domitia Perpignan France
- Association Charles Flahault Toulouges France
| | - Joris A. M. Bertrand
- Laboratoire Génome et Développement des Plantes (LGDP, UMR 5096 UPVD/CNRS) Université de Perpignan Via Domitia Perpignan France
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14
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Cui X, Li C, Qin S, Huang Z, Gan B, Jiang Z, Huang X, Yang X, Li Q, Xiang X, Chen J, Zhao Y, Rong J. High-throughput sequencing-based microsatellite genotyping for polyploids to resolve allele dosage uncertainty and improve analyses of genetic diversity, structure and differentiation: A case study of the hexaploid Camellia oleifera. Mol Ecol Resour 2021; 22:199-211. [PMID: 34260828 DOI: 10.1111/1755-0998.13469] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 07/08/2021] [Accepted: 07/12/2021] [Indexed: 11/30/2022]
Abstract
Conventional microsatellite (simple sequence repeat, SSR) genotyping methods cannot accurately identify polyploid genotypes leading to allele dosage uncertainty, introducing biases in population genetic analysis. Here, a new SSR genotyping method was developed to directly infer accurate polyploid genotypes. The frequency distribution of SSR sequences was obtained based on deep-coverage high-throughput sequencing data. Corrections were performed accounting for the "stutter peak" and amplification efficiency of SSR sequences. Perl scripts and an online SSR genotyping tool "SSRSeq" were provided to process the sequencing data and output genotypes with corrected allele dosages. Hexaploid Camellia oleifera is the dominant woody oilseed crop in China. Understanding the geographical pattern of genetic variation in wild C. oleifera is essential for the conservation and utilization of genetic resources. Six wild C. oleifera populations were sampled across geographical ranges in subtropical evergreen broadleaf forests of China. Using 35 SSR markers, the high-throughput sequencing-based SSRSeq method was applied to obtain accurate hexaploid genotypes of wild C. oleifera. The results demonstrated that the new method could resolve allele dosage uncertainty and considerably improve genetic diversity, structure and differentiation analyses for polyploids. The genetic variation patterns of wild C. oleifera across geographical ranges agree with the "central-marginal hypothesis", stating that genetic diversity is high in the central population and declines from the central to the peripheral populations, and genetic differentiation increases from the centre to the periphery. This method and findings can facilitate the utilization of wild C. oleifera genetic resources for the breeding of cultivated C. oleifera.
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Affiliation(s)
- Xiangyan Cui
- Jiangxi Province Key Laboratory of Watershed Ecosystem Change and Biodiversity, Center for Watershed Ecology, Institute of Life Science and School of Life Sciences, Nanchang University, Nanchang, China
| | - Caihua Li
- Center for Genetic & Genomic Analysis, Genesky Biotechnologies Inc, Shanghai, China
| | - Shengyuan Qin
- Jiangxi Province Key Laboratory of Watershed Ecosystem Change and Biodiversity, Center for Watershed Ecology, Institute of Life Science and School of Life Sciences, Nanchang University, Nanchang, China
| | - Zebin Huang
- Center for Genetic & Genomic Analysis, Genesky Biotechnologies Inc, Shanghai, China
| | - Bin Gan
- Center for Genetic & Genomic Analysis, Genesky Biotechnologies Inc, Shanghai, China
| | | | - Xiaomao Huang
- Jiangxi Province Key Laboratory of Watershed Ecosystem Change and Biodiversity, Center for Watershed Ecology, Institute of Life Science and School of Life Sciences, Nanchang University, Nanchang, China
| | - Xiaoqiang Yang
- Jiangxi Province Key Laboratory of Watershed Ecosystem Change and Biodiversity, Center for Watershed Ecology, Institute of Life Science and School of Life Sciences, Nanchang University, Nanchang, China
| | - Qin Li
- Fudan Development Institute, Fudan University, Shanghai, China
| | - Xiaoguo Xiang
- Jiangxi Province Key Laboratory of Watershed Ecosystem Change and Biodiversity, Center for Watershed Ecology, Institute of Life Science and School of Life Sciences, Nanchang University, Nanchang, China
| | - Jiakuan Chen
- Jiangxi Province Key Laboratory of Watershed Ecosystem Change and Biodiversity, Center for Watershed Ecology, Institute of Life Science and School of Life Sciences, Nanchang University, Nanchang, China.,Fudan Development Institute, Fudan University, Shanghai, China
| | - Yao Zhao
- Jiangxi Province Key Laboratory of Watershed Ecosystem Change and Biodiversity, Center for Watershed Ecology, Institute of Life Science and School of Life Sciences, Nanchang University, Nanchang, China.,Lushan Botanical Garden, Chinese Academy of Sciences, Lushan, China
| | - Jun Rong
- Jiangxi Province Key Laboratory of Watershed Ecosystem Change and Biodiversity, Center for Watershed Ecology, Institute of Life Science and School of Life Sciences, Nanchang University, Nanchang, China.,Lushan Botanical Garden, Chinese Academy of Sciences, Lushan, China
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15
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Ahmad M, Leroy T, Krigas N, Temsch EM, Weiss-Schneeweiss H, Lexer C, Sehr EM, Paun O. Spatial and Ecological Drivers of Genetic Structure in Greek Populations of Alkanna tinctoria (Boraginaceae), a Polyploid Medicinal Herb. FRONTIERS IN PLANT SCIENCE 2021; 12:706574. [PMID: 34335669 PMCID: PMC8317432 DOI: 10.3389/fpls.2021.706574] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 06/16/2021] [Indexed: 06/08/2023]
Abstract
Background and Aims: Quantifying genetic variation is fundamental to understand a species' demographic trajectory and its ability to adapt to future changes. In comparison with diploids, however, genetic variation and factors fostering genetic divergence remain poorly studied in polyploids due to analytical challenges. Here, by employing a ploidy-aware framework, we investigated the genetic structure and its determinants in polyploid Alkanna tinctoria (Boraginaceae), an ancient medicinal herb that is the source of bioactive compounds known as alkannin and shikonin (A/S). From a practical perspective, such investigation can inform biodiversity management strategies. Methods: We collected 14 populations of A. tinctoria within its main distribution range in Greece and genotyped them using restriction site-associated DNA sequencing. In addition, we included two populations of A. sieberi. By using a ploidy-aware genotype calling based on likelihoods, we generated a dataset of 16,107 high-quality SNPs. Classical and model-based analysis was done to characterize the genetic structure within and between the sampled populations, complemented by genome size measurements and chromosomal counts. Finally, to reveal the drivers of genetic structure, we searched for associations between allele frequencies and spatial and climatic variables. Key Results: We found support for a marked regional structure in A. tinctoria along a latitudinal gradient in line with phytogeographic divisions. Several analyses identified interspecific admixture affecting both mainland and island populations. Modeling of spatial and climatic variables further demonstrated a larger contribution of neutral processes and a lesser albeit significant role of selection in shaping the observed genetic structure in A. tinctoria. Conclusion: Current findings provide evidence of strong genetic structure in A. tinctoria mainly driven by neutral processes. The revealed natural genomic variation in Greek Alkanna can be used to further predict variation in A/S production, whereas our bioinformatics approach should prove useful for the study of other non-model polyploid species.
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Affiliation(s)
- Muhammad Ahmad
- Center for Health & Bioresources, AIT Austrian Institute of Technology GmbH, Tulln, Austria
- Department of Botany and Biodiversity Research, University of Vienna, Vienna, Austria
| | - Thibault Leroy
- Department of Botany and Biodiversity Research, University of Vienna, Vienna, Austria
| | - Nikos Krigas
- Institute of Plant Breeding and Genetic Resources, Hellenic Agricultural Organization Demeter, Thessaloniki, Greece
| | - Eva M. Temsch
- Department of Botany and Biodiversity Research, University of Vienna, Vienna, Austria
| | | | - Christian Lexer
- Department of Botany and Biodiversity Research, University of Vienna, Vienna, Austria
| | - Eva Maria Sehr
- Center for Health & Bioresources, AIT Austrian Institute of Technology GmbH, Tulln, Austria
| | - Ovidiu Paun
- Department of Botany and Biodiversity Research, University of Vienna, Vienna, Austria
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16
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Development of novel microsatellite marker panel in threatened tetraploid mahseer, Tor tor (Hamilton 1822) for insights into its genetic diversity and population structure. Meta Gene 2021. [DOI: 10.1016/j.mgene.2021.100880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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17
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Emel SL, Wang S, Metz RP, Spigler RB. Type and intensity of surrounding human land use, not local environment, shape genetic structure of a native grassland plant. Mol Ecol 2021; 30:639-655. [PMID: 33245827 DOI: 10.1111/mec.15753] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2019] [Revised: 11/01/2020] [Accepted: 11/13/2020] [Indexed: 12/28/2022]
Abstract
Landscape heterogeneity can shape genetic structure and functional connectivity of populations. When this heterogeneity imposes variable costs of moving across the landscape, populations can be structured according to a pattern of "isolation by resistance" (IBR). At the same time, divergent local environmental filters can limit gene flow, creating an alternative pattern of "isolation by environment" (IBE). Here, we evaluate IBR and IBE in the insect-pollinated, biennial plant Sabatia angularis (L.) Pursh (Gentianaceae) across serpentine grasslands in the fragmented landscape of SE Pennsylvania, USA using ~4500 neutral SNP loci. Specifically, we test the extent to which radical alteration of the landscape matrix by humans has fundamentally altered the cost of movement, imprinting a pattern of IBR dictated by land use type and intensity, and the potential for IBE in relation to a gradient of heavy metal concentrations found in serpentine soil. We reveal a strong signal of IBR and a weak signal of IBE across sites, indicating the greater importance of the landscape matrix in shaping genetic structure of S. angularis populations in the study region. Based on Circuitscape and least cost path approaches, we find that both low- and high-intensity urbanization resist gene flow by orders of magnitude greater than "natural" habitats, although resistance to low-intensity urbanization weakens at larger spatial scales. While cropland presents a substantially lower barrier than urban development, cumulative human land use surrounding populations predicts within-population genetic diversity and inbreeding in S. angularis. Our results emphasize the role of forest buffers and corridors in facilitating gene flow between serpentine grassland patches and averting local extinction of plant populations.
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Affiliation(s)
- Sarah L Emel
- Department of Biology, Temple University, Philadelphia, PA, USA.,Department of Biology, Indiana University of Pennsylvania, Indiana, PA, USA
| | - Shichen Wang
- Genomics and Bioinformatics Service, Texas A&M AgriLife Research, TX, USA
| | - Richard P Metz
- Genomics and Bioinformatics Service, Texas A&M AgriLife Research, TX, USA
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18
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Hojsgaard D, Schartl M. Skipping sex: A nonrecombinant genomic assemblage of complementary reproductive modules. Bioessays 2020; 43:e2000111. [PMID: 33169369 DOI: 10.1002/bies.202000111] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 09/26/2020] [Accepted: 09/29/2020] [Indexed: 02/03/2023]
Abstract
The unusual occurrence and developmental diversity of asexual eukaryotes remain a puzzle. De novo formation of a functioning asexual genome requires a unique assembly of sets of genes or gene states to disrupt cellular mechanisms of meiosis and gametogenesis, and to affect discrete components of sexuality and produce clonal or hemiclonal offspring. We highlight two usually overlooked but essential conditions to understand the molecular nature of clonal organisms, that is, a nonrecombinant genomic assemblage retaining modifiers of the sexual program, and a complementation between altered reproductive components. These subtle conditions are the basis for physiologically viable and genetically balanced transitions between generations. Genomic and developmental evidence from asexual animals and plants indicates the lack of complementation of molecular changes in the sexual reproductive program is likely the main cause of asexuals' rarity, and can provide an explanatory frame for the developmental diversity and lability of developmental patterns in some asexuals as well as for the discordant time to extinction estimations.
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Affiliation(s)
- Diego Hojsgaard
- Department of Systematics, Biodiversity and Evolution of Plants (with Herbarium), Albrecht-von-Haller Institute for Plant Sciences, University of Goettingen, Goettingen, Germany
| | - Manfred Schartl
- Department of Developmental Biochemistry, Biocenter, University of Wuerzburg, Wuerzburg, Germany.,The Xiphophorus Genetic Stock Center, Department of Chemistry and Biochemistry, Texas State University, San Marcos, Texas, USA
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19
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Ahrens CW, James EA, Miller AD, Scott F, Aitken NC, Jones AW, Lu-Irving P, Borevitz JO, Cantrill DJ, Rymer PD. Spatial, climate and ploidy factors drive genomic diversity and resilience in the widespread grass Themeda triandra. Mol Ecol 2020; 29:3872-3888. [PMID: 32885504 DOI: 10.1111/mec.15614] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 08/17/2020] [Accepted: 08/17/2020] [Indexed: 12/27/2022]
Abstract
Global climate change poses a significant threat to natural communities around the world, with many plant species showing signs of climate stress. Grassland ecosystems are not an exception, with climate change compounding contemporary pressures such as habitat loss and fragmentation. In this study, we assess the climate resilience of Themeda triandra, a foundational species and the most widespread plant in Australia, by assessing the relative contributions of spatial, environmental and ploidy factors to contemporary genomic variation. Reduced-representation genome sequencing on 472 samples from 52 locations was used to test how the distribution of genomic variation, including ploidy polymorphism, supports adaptation to hotter and drier climates. We explicitly quantified isolation by distance (IBD) and isolation by environment (IBE) and predicted genomic vulnerability of populations to future climates based on expected deviation from current genomic composition. We found that a majority (54%) of genomic variation could be attributed to IBD, while an additional 22% (27% when including ploidy information) could be explained by two temperature and two precipitation climate variables demonstrating IBE. Ploidy polymorphisms were common within populations (31/52 populations), indicating that ploidy mixing is characteristic of T. triandra populations. Genomic vulnerabilities were found to be heterogeneously distributed throughout the landscape, and our analysis suggested that ploidy polymorphism, along with other factors linked to polyploidy, reduced vulnerability to future climates by 60% (0.25-0.10). Our data suggests that polyploidy may facilitate adaptation to hotter climates and highlight the importance of incorporating ploidy in adaptive management strategies to promote the resilience of this and other foundation species.
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Affiliation(s)
- Collin W Ahrens
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia.,Royal Botanic Gardens Victoria, Melbourne, VIC, Australia
| | | | - Adam D Miller
- School of Life and Environmental Sciences, Centre for Integrative Ecology, Deakin University, Warrnambool, VIC, Australia
| | - Ferguson Scott
- Research School of Biology, Australian National University, Canberra, ACT, Australia
| | - Nicola C Aitken
- Research School of Biology, Australian National University, Canberra, ACT, Australia
| | - Ashley W Jones
- Research School of Biology, Australian National University, Canberra, ACT, Australia
| | - Patricia Lu-Irving
- Research Centre for Ecosystem Resilience, Australian Institute of Botanical Science, Royal Botanic Garden, Sydney, NSW, Australia
| | - Justin O Borevitz
- Research School of Biology, Australian National University, Canberra, ACT, Australia
| | | | - Paul D Rymer
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
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20
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Gargiulo R, Worswick G, Arnold C, Pike LJ, Cowan RS, Hardwick KA, Chapman T, Fay MF. Conservation of the Threatened Species, Pulsatilla vulgaris Mill. (Pasqueflower), is Aided by Reproductive System and Polyploidy. J Hered 2020; 110:618-628. [PMID: 31102445 DOI: 10.1093/jhered/esz035] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Accepted: 05/16/2019] [Indexed: 11/13/2022] Open
Abstract
Population loss due to habitat disturbance is a major concern in biodiversity conservation. Here we investigate the genetic causes of the demographic decline observed in English populations of Pulsatilla vulgaris and the consequences for conservation. Using 10 nuclear microsatellite markers, we compare genetic variation in wild populations with restored and seed-regenerated populations (674 samples). Emergence of genetic structure and loss of allelic variation in natural populations are not as evident as expected from demographic trends. Restored populations show genetic variation comparable to their source populations and, in general, to the wild ones. Genetic homogeneity is observed in regeneration trials, although some alleles not captured in source populations are detected. We infer that polyploidy, longevity, and clonal reproduction have provided P. vulgaris with the standing genetic variation necessary to make the species resilient to the effects of demographic decline, suggesting that the use of multiple sources for reintroduction may be beneficial to mimic natural gene flow and the availability of multiple allele copies typical of polyploid species.
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Affiliation(s)
| | | | | | | | | | - Kate A Hardwick
- Royal Botanic Gardens, Kew, Millennium Seed Bank, Ardingly, UK
| | - Ted Chapman
- Royal Botanic Gardens, Kew, Millennium Seed Bank, Ardingly, UK
| | - Michael F Fay
- Royal Botanic Gardens, Kew, Richmond, UK.,School of Plant Biology, University of Western Australia, Crawley, Western Australia, Australia
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21
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Beirinckx L, Vanschoenwinkel B, Triest L. Hidden Hybridization and Habitat Differentiation in a Mediterranean Macrophyte, the Euryhaline Genus Ruppia. FRONTIERS IN PLANT SCIENCE 2020; 11:830. [PMID: 32754168 PMCID: PMC7366321 DOI: 10.3389/fpls.2020.00830] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 05/22/2020] [Indexed: 06/11/2023]
Abstract
In many aquatic plant taxa, classification based on morphology has always been difficult. Molecular markers revealed that the complexity in several of these aquatic taxa could be addressed to recurrent hybridization events and cryptic species diversity. The submerged macrophyte genus Ruppia is one of these aquatic genera with a complex taxonomy due to the absence of clear distinguishable traits and several hybridization events. Two species co-exist throughout Europe, R. maritima and R. spiralis (previously known as R. cirrhosa), but recent molecular studies also found several indications of hybridization, introgression and chloroplast capture between these species. However, the full extent and frequency of hybridization and introgression in this genus has not been studied so far, nor is it clear how these hybrid lineages can co-exist locally with their parental species. In this paper, we wanted to detect whether a single coastal wetland where both species co-exist can act as a Ruppia hybrid zone. As a case study, we chose the Camargue, a Mediterranean coastal wetland that harbors a wide diversity in aquatic habitats, especially in terms of salinity and hydro-regime. We sampled several Ruppia populations within this wetland. To identify each sample and reconstruct the local genetic structure of the two parental species and their hybrids, we used both chloroplast and nuclear microsatellite markers. Afterward, we tested whether different species had different habitat preferences. Our results confirmed that R. maritima and R. spiralis are two strongly divergent species with different reproductive ecologies and different habitat preferences. This prevents frequent hybridization and consequently we could not detect any trace of a recent hybridization event. However, we found several populations of later-generation hybrids, including a population of R. maritima x hybrid backcrosses. The hybrid populations occupy a different habitat and are genetically distinct from their parental species, although they tend to be morphological similar to parental R. maritima. Although local hybridization and introgression in Ruppia is less frequent than we expected, the taxonomy of Ruppia is complicated due to ancient hybridizations and several back-crossings.
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Affiliation(s)
- Lise Beirinckx
- Ecology and Biodiversity Research Group, Plant Biology and Nature Management, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Bram Vanschoenwinkel
- Community Ecology Laboratory, Department of Biology, Vrije Universiteit Brussel (VUB), Brussels, Belgium
- Centre for Environmental Management, University of the Free State, Bloemfontein, South Africa
| | - Ludwig Triest
- Ecology and Biodiversity Research Group, Plant Biology and Nature Management, Vrije Universiteit Brussel (VUB), Brussels, Belgium
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22
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Wang H, Yin X, Yin D, Li L, Xiao H. Population genetic structures of two ecologically distinct species Betula platyphylla and B. ermanii inferred based on nuclear and chloroplast DNA markers. Ecol Evol 2019; 9:11406-11419. [PMID: 31641482 PMCID: PMC6802015 DOI: 10.1002/ece3.5643] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2018] [Revised: 08/19/2019] [Accepted: 08/20/2019] [Indexed: 01/26/2023] Open
Abstract
Climatic oscillations during the last glacial maximum (LGM) significantly affected the distribution patterns and genetic structure of extant plants. Northeast China (NEC) is a major biodiversity center in East Asia, and the influence of historical climate change on NEC populations is critical for understanding species responses to future climate change. However, only a few phylogeographic studies of cool temperate deciduous tree species have been conducted in the area, and results are inconsistent for species with different niches or distribution areas. We employed multiple chloroplast and nuclear markers to investigate the genetic structure of two ecologically contrasting species, Betula platyphylla and B. ermanii, in NEC. Rare haplotypes were identified in the chloroplast genome of these species, and both exhibited high levels of nucleotide diversity based on a fragment of the nuclear gene G3PDH and microsatellites. Moreover, significant phylogeographic structure was detected for B. platyphylla, suggesting that these populations had recolonized from independent glacial refuges, whereas no genetic structure was found for B. ermanii. OPEN RESEARCH BADGES The nSSR datasets used in the current study and the table of pairwise FST (below diagonal) and its standardized F'ST (above diagonal) among 25 populations based on seven SSRs are available from the Dryad (DOI: https://doi.org/10.5061/dryad.230d176). Sequences generated from this study were deposited in GenBank under Accession nos. KY199568-KY200162 and MK819541-MK819970.
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Affiliation(s)
- Hua‐Ying Wang
- Key Laboratory of Molecular Epigenetics of Ministry of EducationNortheast Normal UniversityChangchunChina
| | - Xiao Yin
- Key Laboratory of Molecular Epigenetics of Ministry of EducationNortheast Normal UniversityChangchunChina
| | - Dong‐Xu Yin
- Key Laboratory of Molecular Epigenetics of Ministry of EducationNortheast Normal UniversityChangchunChina
| | - Lin Li
- Key Laboratory of Molecular Epigenetics of Ministry of EducationNortheast Normal UniversityChangchunChina
| | - Hong‐Xing Xiao
- Key Laboratory of Molecular Epigenetics of Ministry of EducationNortheast Normal UniversityChangchunChina
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23
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Wos G, Mořkovská J, Bohutínská M, Šrámková G, Knotek A, Lučanová M, Španiel S, Marhold K, Kolář F. Role of ploidy in colonization of alpine habitats in natural populations of Arabidopsis arenosa. ANNALS OF BOTANY 2019; 124:255-268. [PMID: 31185073 PMCID: PMC6758580 DOI: 10.1093/aob/mcz070] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Accepted: 05/17/2019] [Indexed: 05/13/2023]
Abstract
BACKGROUND AND AIMS Polyploidy is an important driver of plant diversification and adaptation to novel environments. As a consequence of genome doubling, polyploids often exhibit greater colonizing ability or occupy a wider ecological niche than diploids. Although elevation has been traditionally considered as a key driver structuring ploidy variation, we do not know if environmental and phenotypic differentiation among ploidy cytotypes varies along an elevational gradient. Here, we tested for the consequences of genome duplication on genetic diversity, phenotypic variation and habitat preferences on closely related diploid and tetraploid populations that coexist along approx. 2300 m of varying elevation. METHODS We sampled and phenotyped 45 natural diploid and tetraploid populations of Arabidopsis arenosa in one mountain range in Central Europe (Western Carpathians) and recorded abiotic and biotic variables at each collection site. We inferred genetic variation, population structure and demographic history in a sub-set of 29 populations genotyped for approx. 36 000 single nucleotide polymorphisms. KEY RESULTS We found minor effects of polyploidy on colonization of alpine stands and low genetic differentiation between the two cytotypes, mirroring recent divergence of the polyploids from the local diploid lineage and repeated reticulation events among the cytotypes. This pattern was corroborated by the absence of ecological niche differentiation between the two cytotypes and overall phenotypic similarity at a given elevation. CONCLUSIONS The case of A. arenosa contrasts with previous studies that frequently showed clear niche differentiation between cytotypes. Our work stresses the importance of considering genetic structure and past demographic processes when interpreting the patterns of ploidy distributions, especially in species that underwent recent polyploidization events.
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Affiliation(s)
- Guillaume Wos
- Department of Botany, Charles University, Prague, Czech Republic
| | - Jana Mořkovská
- Department of Botany, Charles University, Prague, Czech Republic
| | - Magdalena Bohutínská
- Department of Botany, Charles University, Prague, Czech Republic
- Institute of Botany, The Czech Academy of Sciences, Průhonice, Czech Republic
| | | | - Adam Knotek
- Department of Botany, Charles University, Prague, Czech Republic
| | - Magdalena Lučanová
- Department of Botany, Charles University, Prague, Czech Republic
- Institute of Botany, The Czech Academy of Sciences, Průhonice, Czech Republic
| | - Stanislav Španiel
- Department of Botany, Charles University, Prague, Czech Republic
- Institute of Botany, Plant Science and Biodiversity Centre, Slovak Academy of Sciences, Bratislava, Slovak Republic
| | - Karol Marhold
- Department of Botany, Charles University, Prague, Czech Republic
- Institute of Botany, Plant Science and Biodiversity Centre, Slovak Academy of Sciences, Bratislava, Slovak Republic
| | - Filip Kolář
- Department of Botany, Charles University, Prague, Czech Republic
- Institute of Botany, The Czech Academy of Sciences, Průhonice, Czech Republic
- Institute of Botany, University of Innsbruck, Innsbruck, Austria
- For correspondence. E-mail
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24
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Hughes AR, Hanley TC, Byers JE, Grabowski JH, McCrudden T, Piehler MF, Kimbro DL. Genetic diversity and phenotypic variation within hatchery-produced oyster cohorts predict size and success in the field. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2019; 29:e01940. [PMID: 31148283 DOI: 10.1002/eap.1940] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 04/03/2019] [Accepted: 04/17/2019] [Indexed: 06/09/2023]
Abstract
The rapid growth of the aquaculture industry to meet global seafood demand offers both risks and opportunities for resource management and conservation. In particular, hatcheries hold promise for stock enhancement and restoration, yet cultivation practices may lead to enhanced variation between populations at the expense of variation within populations, with uncertain implications for performance and resilience. To date, few studies have assessed how production techniques impact genetic diversity and population structure, as well as resultant trait variation in and performance of cultivated offspring. We collaborated with a commercial hatchery to produce multiple cohorts of the eastern oyster (Crassostrea virginica) from field-collected broodstock using standard practices. We recorded key characteristics of the broodstock (male : female ratio, effective population size), quantified the genetic diversity of the resulting cohorts, and tested their trait variation and performance across multiple field sites and experimental conditions. Oyster cohorts produced under the same conditions in a single hatchery varied almost twofold in genetic diversity. In addition, cohort genetic diversity was a significant positive predictor of oyster performance traits, including initial size and survival in the field. Oyster cohorts produced in the hatchery had lower within-cohort genetic variation and higher among-cohort genetic structure than adults surveyed from the same source sites. These findings are consistent with "sweepstakes reproduction" in oysters, even when manually spawned. A readily measured characteristic of broodstock, the ratio of males to females, was positively correlated with within-cohort genetic diversity of the resulting offspring. Thus, this metric may offer a tractable way both to meet short-term production goals for seafood demand and to ensure the capacity of hatchery-produced stock to achieve conservation objectives, such as the recovery of self-sustaining wild populations.
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Affiliation(s)
- A Randall Hughes
- Marine Science Center, Northeastern University, Nahant, Massachusetts, 01908 , USA
| | - Torrance C Hanley
- Marine Science Center, Northeastern University, Nahant, Massachusetts, 01908 , USA
| | - James E Byers
- Odum School of Ecology, University of Georgia, Athens, Georgia, 30602, USA
| | - Jonathan H Grabowski
- Marine Science Center, Northeastern University, Nahant, Massachusetts, 01908 , USA
| | - Tom McCrudden
- Research Aquaculture, Inc., Tequesta, Florida, 33469, USA
| | - Michael F Piehler
- Institute of Marine Sciences, University of North Carolina at Chapel Hill, Morehead City, North Carolina, 28557, USA
| | - David L Kimbro
- Marine Science Center, Northeastern University, Nahant, Massachusetts, 01908 , USA
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Rodríguez-Rodríguez P, G. Fernández de Castro A, Seguí J, Traveset A, Sosa PA. Alpine species in dynamic insular ecosystems through time: conservation genetics and niche shift estimates of the endemic and vulnerable Viola cheiranthifolia. ANNALS OF BOTANY 2019; 123:505-519. [PMID: 30307538 PMCID: PMC6377099 DOI: 10.1093/aob/mcy185] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Accepted: 09/19/2018] [Indexed: 06/08/2023]
Abstract
BACKGROUND AND AIMS Alpine oceanic ecosystems are considered amongst the most ephemeral and restricted habitats, with a biota highly vulnerable to climate changes and disturbances. As an example of an alpine insular endemic, the past and future population genetic structure and diversity, and the future distribution of Viola cheiranthifolia (Violaceae), endemic to Tenerife (Canary Islands), were estimated. The main goals were to predict distribution changes of this alpine oceanic plant under climate change, and to assist in actions for its conservation. METHODS To perform population genetic analysis, 14 specific microsatellite markers and algorithms which considered the polyploid condition of V. cheiranthifolia were employed. The niche modelling approach incorporated temperature gradients, topography and snow cover maps. Models were projected into climate change scenarios to assess the extent of the altitudinal shifts of environmental suitability. Finally, simulations were performed to predict whether the environmental suitability loss will affect the genetic diversity of populations. KEY RESULTS Viola cheiranthifolia presents short dispersal capacity, moderate levels of genetic diversity and a clear population genetic structure divided into two main groups (Teide and Las Cañadas Wall), showing signs of recolonization dynamics after volcanic eruptions. Future estimates of the distribution of the study populations also showed that, despite being extremely vulnerable to climate change, the species will not lose all its potential area in the next decades. The simulations to estimate genetic diversity loss show that it is correlated to suitability loss, especially in Las Cañadas Wall. CONCLUSIONS The low dispersal capacity of V. cheiranthifolia, coupled with herbivory pressure, mainly from rabbits, will make its adaptation to future climate conditions in this fragile alpine ecosystem difficult. Conservation actions should be focused on herbivore control, population reinforcement and surveillance of niche shifts, especially in Guajara, which represents the oldest isolated population and a genetic reservoir for the species.
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Affiliation(s)
- Priscila Rodríguez-Rodríguez
- Instituto Universitario de Estudios Ambientales y Recursos Naturales (IUNAT), Universidad de Las Palmas de Gran Canaria, Campus Universitario de Tafira, Las Palmas de Gran Canaria, Canary Islands, Spain
| | | | - Jaume Seguí
- Global Change Research Group, Mediterranean Institute for Advanced Studies (CSIC-UIB), c/ Miquel Marquès, Esporles Balearic Islands, Spain
| | - Anna Traveset
- Global Change Research Group, Mediterranean Institute for Advanced Studies (CSIC-UIB), c/ Miquel Marquès, Esporles Balearic Islands, Spain
| | - Pedro A Sosa
- Instituto Universitario de Estudios Ambientales y Recursos Naturales (IUNAT), Universidad de Las Palmas de Gran Canaria, Campus Universitario de Tafira, Las Palmas de Gran Canaria, Canary Islands, Spain
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Ferretti L, Ribeca P, Ramos-Onsins SE. The Site Frequency/Dosage Spectrum of Autopolyploid Populations. Front Genet 2018; 9:480. [PMID: 30405691 PMCID: PMC6207136 DOI: 10.3389/fgene.2018.00480] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Accepted: 09/28/2018] [Indexed: 01/15/2023] Open
Abstract
The Site Frequency Spectrum (SFS) and the heterozygosity of allelic variants are among the most important summary statistics for population genetic analysis of diploid organisms. We discuss the generalization of these statistics to populations of autopolyploid organisms in terms of the joint Site Frequency/Dosage Spectrum and its expected value for autopolyploid populations that follow the standard neutral model. Based on these results, we present estimators of nucleotide variability from High-Throughput Sequencing (HTS) data of autopolyploids and discuss potential issues related to sequencing errors and variant calling. We use these estimators to generalize Tajima's D and other SFS-based neutrality tests to HTS data from autopolyploid organisms. Finally, we discuss how these approaches fail when the number of individuals is small. In fact, in autopolyploids there are many possible deviations from the Hardy–Weinberg equilibrium, each reflected in a different shape of the individual dosage distribution. The SFS from small samples is often dominated by the shape of these deviations of the dosage distribution from its Hardy–Weinberg expectations.
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Dembicz I, Szczeparska L, Moysiyenko II, Wódkiewicz M. High genetic diversity in fragmented Iris pumila L. populations in Ukrainian steppe enclaves. Basic Appl Ecol 2018. [DOI: 10.1016/j.baae.2018.02.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Jighly A, Lin Z, Forster JW, Spangenberg GC, Hayes BJ, Daetwyler HD. Insights into population genetics and evolution of polyploids and their ancestors. Mol Ecol Resour 2018; 18:1157-1172. [PMID: 29697892 DOI: 10.1111/1755-0998.12896] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Accepted: 03/13/2018] [Indexed: 01/10/2023]
Abstract
We have developed the first comprehensive simulator for polyploid genomes (PolySim) and demonstrated its value by performing large-scale simulations to examine the effect of different population parameters on the evolution of polyploids. PolySim is unlimited in terms of ploidy, population size or number of simulated loci. Our process considered the evolution of polyploids from diploid ancestors, polysomic inheritance, inbreeding, recombination rate change in polyploids and gene flow from lower to higher ploidies. We compared the number of segregating single nucleotide polymorphisms, minor allele frequency, heterozygosity, R2 and average kinship relatedness between different simulated scenarios, and to real data from polyploid species. As expected, allotetraploid populations showed no difference from their ancestral diploids when population size remained constant and there was no gene flow or multivalent (MV) pairing between subgenomes. Autotetraploid populations showed significant differences from their ancestors for most parameters and diverged from their ancestral populations faster than allotetraploids. Autotetraploids can have significantly higher heterozygosity, relatedness and extended linkage disequilibrium compared with allotetraploids. Interestingly, autotetraploids were more sensitive to increasing selfing rate and decreasing population size. MV formation can homogenize allotetraploid subgenomes, but this homogenization requires a higher MV rate than previously proposed. Our results can be considered as the first building block to understand polyploid population evolutionary dynamics. PolySim can be used to simulate a wide variety of polyploid organisms that mimic empirical populations, which, in combination with quantitative genetics tools, can be used to investigate the power of genomewide association, genomic selection or breeding programme designs in these species.
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Affiliation(s)
- Abdulqader Jighly
- Agriculture Victoria, AgriBio, Centre for AgriBiosciences, Bundoora, Vic., Australia
- School of Applied Systems Biology, La Trobe University, Bundoora, Vic., Australia
| | - Zibei Lin
- Agriculture Victoria, AgriBio, Centre for AgriBiosciences, Bundoora, Vic., Australia
| | - John W Forster
- Agriculture Victoria, AgriBio, Centre for AgriBiosciences, Bundoora, Vic., Australia
- School of Applied Systems Biology, La Trobe University, Bundoora, Vic., Australia
| | - German C Spangenberg
- Agriculture Victoria, AgriBio, Centre for AgriBiosciences, Bundoora, Vic., Australia
- School of Applied Systems Biology, La Trobe University, Bundoora, Vic., Australia
| | - Ben J Hayes
- Agriculture Victoria, AgriBio, Centre for AgriBiosciences, Bundoora, Vic., Australia
- Queensland Alliance for Agriculture and Food Innovation, Centre for Animal Science, University of Queensland, St Lucia, Qld, Australia
| | - Hans D Daetwyler
- Agriculture Victoria, AgriBio, Centre for AgriBiosciences, Bundoora, Vic., Australia
- School of Applied Systems Biology, La Trobe University, Bundoora, Vic., Australia
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McKinney GJ, Waples RK, Pascal CE, Seeb LW, Seeb JE. Resolving allele dosage in duplicated loci using genotyping-by-sequencing data: A path forward for population genetic analysis. Mol Ecol Resour 2018; 18:570-579. [DOI: 10.1111/1755-0998.12763] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Revised: 01/18/2018] [Accepted: 01/19/2018] [Indexed: 11/29/2022]
Affiliation(s)
- Garrett J. McKinney
- School of Aquatic and Fishery Sciences; University of Washington; Seattle WA USA
| | - Ryan K. Waples
- School of Aquatic and Fishery Sciences; University of Washington; Seattle WA USA
| | - Carita E. Pascal
- School of Aquatic and Fishery Sciences; University of Washington; Seattle WA USA
| | - Lisa W. Seeb
- School of Aquatic and Fishery Sciences; University of Washington; Seattle WA USA
| | - James E. Seeb
- School of Aquatic and Fishery Sciences; University of Washington; Seattle WA USA
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31
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Meirmans PG, Liu S, van Tienderen PH. The Analysis of Polyploid Genetic Data. J Hered 2018; 109:283-296. [DOI: 10.1093/jhered/esy006] [Citation(s) in RCA: 110] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Accepted: 01/20/2018] [Indexed: 12/14/2022] Open
Affiliation(s)
- Patrick G Meirmans
- Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, the Netherlands
| | - Shenglin Liu
- Department of Bioscience, Aarhus University, Aarhus, Denmark
| | - Peter H van Tienderen
- Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, the Netherlands
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Parra-Nunez P, Pradillo M, Santos JL. Competition for Chiasma Formation Between Identical and Homologous (But Not Identical) Chromosomes in Synthetic Autotetraploids of Arabidopsis thaliana. FRONTIERS IN PLANT SCIENCE 2018; 9:1924. [PMID: 30687342 PMCID: PMC6333688 DOI: 10.3389/fpls.2018.01924] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 12/11/2018] [Indexed: 05/03/2023]
Abstract
Polyploid organisms provide additional opportunities to study meiosis in a more complex context since more than two potential homologous chromosomes are available. When the chromosome complement of a diploid individual is duplicated, each chromosome is accompanied by one identical and two homologous chromosomes within the same nucleus. In this situation, a competition in pairing/synapsis/chiasma formation between identical and homologous (but not necessarily identical) chromosomes can occur. Several studies have been conducted in different species to address whether there are preferences in crossover formation between identical rather than homologous chromosomes. In this study, multivalent and chiasma frequencies were cytologically analyzed in synthetic autotetraploids of Arabidopsis thaliana including the accessions Col, Ler, and the Col/Ler hybrid. Fluorescence in situ hybridization was conducted to identify each chromosome at metaphase I. The new Col and Ler tetraploids showed high multivalent frequencies, exceeding the theoretical 66.66% expected on a simple random end-pairing model, thus indicating that there are more than two autonomous synaptic sites per chromosome despite their small size. However, a significant excess of bivalent pairs was found in the Col/Ler hybrid, mainly due to the contribution of chromosomes 2 and 3. The mean chiasma frequencies of the three artificial autotetraploids were about twofold the corresponding mean cell chiasma frequencies of their diploid counterparts. The relative contribution of each chromosome to the total chiasma frequency was similar in the three genotypes, with the exception of a lower contribution of chromosome 3 in the hybrid. Preferences for chiasma formation between identical and homologous chromosomes were analyzed in Col/Ler 4x, taking advantage of the cytological differences between the accessions: variations in the size of the 45S rDNA region on the short arm of chromosome 2 and changes in the size and localization of the 5S rDNA region in chromosome 3. We observed a different behavior of chromosomes 2 and 3, i.e., random chiasma formation between identical and homologous chromosomes 2, and preferences for chiasma formation between homologous chromosomes 3. Hence, our results reveal the existence of chromosome-specific mechanisms responsible for these preferences.
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Griswold CK, Williamson MW. A two-locus model of selection in autotetraploids: Chromosomal gametic disequilibrium and selection for an adaptive epistatic gene combination. Heredity (Edinb) 2017; 119:314-327. [PMID: 28832578 PMCID: PMC5637366 DOI: 10.1038/hdy.2017.44] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2017] [Revised: 06/23/2017] [Accepted: 06/23/2017] [Indexed: 11/08/2022] Open
Abstract
In this paper, we present a two-locus model of selection for an autotetraploid population. We also investigate a measure of disequilibrium that occurs between homologous chromosomes in the diploid gametes of autotetraploids, namely chromosomal gametic disequilibrium. We apply the model and measure of disequilibrium to compare how an adaptive epistatic gene combination is inherited and selected for in an autotetraploid versus diploid population. Autotetraploids are expected to have higher genomic mutation and recombination rates relative to diploids, due to a greater ploidy level. These two processes can work in opposition in terms of selection for adaptive epistatic gene combinations. While a higher genomic mutation rate can generate the alleles that confer an epistatic combination more quickly, a higher recombination rate is expected to break the combination down more quickly. We show that chromosomal gametic disequilibrium in autotetraploids can potentially compensate for less linkage disequilibrium in autotetraploids. We also explore how double reduction affects the inheritance of and selection for an epistatic gene combination. Over all, our analysis provides theoretical evidence that adaptive epistatic combinations can be selected for more efficiently in autotetraploids versus diploids. This may provide insight into empirical work that finds epistasis has a role in causing population differentiation between autotetraploid plant populations.
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Affiliation(s)
- C K Griswold
- Department of Integrative Biology, University of Guelph, Guelph, ON, Canada
| | - M W Williamson
- Department of Integrative Biology, University of Guelph, Guelph, ON, Canada
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Field DL, Broadhurst LM, Elliott CP, Young AG. Population assignment in autopolyploids. Heredity (Edinb) 2017; 119:389-401. [PMID: 28976495 DOI: 10.1038/hdy.2017.51] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Revised: 07/07/2017] [Accepted: 07/24/2017] [Indexed: 11/09/2022] Open
Abstract
Understanding the patterns of contemporary gene dispersal within and among populations is of critical importance to population genetics and in managing populations for conservation. In contrast to diploids, there are few studies of gene dispersal in autopolyploids, in part due to complex polysomic inheritance and genotype ambiguity. Here we develop a novel approach for population assignment for codominant markers for autotetraploids and autohexaploids. This method accounts for polysomic inheritance, unreduced gametes and unknown allele dosage. It can also utilise information regarding the origin and genotype of one parent for population assignment of maternal or paternal parents. Using simulations, we demonstrate that our approach achieves high levels of accuracy for assignment even when population divergence is low (FST~0.06) and with only 12 microsatellite loci. We also show that substantially higher accuracy is achieved when known maternal information is utilised, regardless of whether allele dosage is known. Although this novel method exhibited near identical levels of accuracy to Structure when population divergence was high, it performed substantially better for most parameters at moderate (FST=0.06) to low levels of divergence (FST=0.03). These methods fill an important gap in the toolset for autopolyploids and pave the way for investigating contemporary gene dispersal in a widespread group of organisms.
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Affiliation(s)
- D L Field
- Department of Botany and Biodiversity Research, University of Vienna, Faculty of Life Sciences, Vienna, Austria
| | | | - C P Elliott
- Biodiversity Conservation Centre, Kings Park, Western Australia, Australia
| | - A G Young
- CSIRO Plant Industry, Canberra, ACT, Australia
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Martins TR, Jiang P, Rausher MD. How petals change their spots: cis-regulatory re-wiring in Clarkia (Onagraceae). THE NEW PHYTOLOGIST 2017; 216:510-518. [PMID: 27597114 DOI: 10.1111/nph.14163] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2016] [Accepted: 07/26/2016] [Indexed: 05/19/2023]
Abstract
A long-standing question in evolutionary developmental biology is how new traits evolve. Although most floral pigmentation studies have focused on how pigment intensity and composition diversify, few, if any, have explored how a pattern element can shift position. In the present study, we examine the genetic changes underlying shifts in the position of petal spots in Clarkia. Comparative transcriptome analyses were used to identify potential candidate genes responsible for spot formation. Co-segregation analyses in F2 individuals segregating for different spot positions, quantitative PCR, and pyrosequencing, were used to confirm the role of the candidate gene in determining spot position. Transient expression assays were used to identify the expression domain of different alleles. An R2R3Myb transcription factor (CgMyb1) activated spot formation, and different alleles of CgMyb1 were expressed in different domains, leading to spot formation in different petal locations. Reporter assays revealed that promoters from different alleles determine different locations of expression. The evolutionary shift in spot position is due to one or more cis-regulatory changes in the promoter of CgMyb1, indicating that shifts in pattern element position can be caused by changes in a single gene, and that cis-regulatory rewiring can be used to alter the relative position of an existing character.
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Affiliation(s)
- Talline R Martins
- Department of Biology, Duke University, Durham, NC, 27708, USA
- Department of Agriculture, Nutrition and Veterinary Sciences, University of Nevada, Reno, NV, 89557, USA
| | - Peng Jiang
- Department of Biology, Duke University, Durham, NC, 27708, USA
| | - Mark D Rausher
- Department of Biology, Duke University, Durham, NC, 27708, USA
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Genetic differentiation and diversity of two sympatric subspecies of Castilleja affinis; a comparison between the endangered serpentine endemic (spp. neglecta) and its widespread congener (ssp. affinis). CONSERV GENET 2017. [DOI: 10.1007/s10592-017-1009-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Karlin EF, Smouse PE. Allo-allo-triploid Sphagnum × falcatulum: single individuals contain most of the Holantarctic diversity for ancestrally indicative markers. ANNALS OF BOTANY 2017; 120:221-231. [PMID: 28088765 PMCID: PMC5737827 DOI: 10.1093/aob/mcw269] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2016] [Accepted: 11/28/2016] [Indexed: 05/28/2023]
Abstract
BACKGROUND AND AIMS Allopolyploids exhibit both different levels and different patterns of genetic variation than are typical of diploids. However, scant attention has been given to the partitioning of allelic information and diversity in allopolyploids, particularly that among homeologous monoploid components of the hologenome. Sphagnum × falcatulum is a double allopolyploid peat moss that spans a considerable portion of the Holantarctic. With monoploid genomes from three ancestral species, this organism exhibits a complex evolutionary history involving serial inter-subgeneric allopolyploidizations. METHODS Studying populations from three disjunct regions [South Island (New Zealand); Tierra de Fuego archipelago (Chile, Argentina); Tasmania (Australia)], allelic information for five highly stable microsatellite markers that differed among the three (ancestral) monoploid genomes was examined. Using Shannon information and diversity measures, the holoploid information, as well as the information within and among the three component monoploid genomes, was partitioned into separate components for individuals within and among populations and regions, and those information components were then converted into corresponding diversity measures. KEY RESULTS The majority (76 %) of alleles detected across these five markers are most likely to have been captured by hybridization, but the information within each of the three monoploid genomes varied, suggesting a history of recurrent allopolyploidization between ancestral species containing different levels of genetic diversity. Information within individuals, equivalent to the information among monoploid genomes (for this dataset), was relatively stable, and represented 83 % of the grand total information across the Holantarctic, with both inter-regional and inter-population diversification each accounting for about 5 % of the total information. CONCLUSIONS Sphagnum × falcatulum probably inherited the great majority of its genetic diversity at these markers by reticulation, rather than by subsequent evolutionary radiation. However, some post-hybridization genetic diversification has become fixed in at least one regional population. Methodology allowing statistical analysis of any ploidy level is presented.
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Affiliation(s)
- Eric F. Karlin
- Environmental Science, School of Theoretical & Applied Science, Ramapo College, Mahwah, NJ 07430-1680, USA
| | - Peter E. Smouse
- Department of Ecology, Evolution, and Natural Resources, School of Environmental & Biological Sciences, Rutgers University, New Brunswick, NJ 08901-8551, USA
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Genetic structure, diversity, and hybridization in populations of the rare arctic relict Euphrasia hudsoniana (Orobanchaceae) and its invasive congener Euphrasia stricta. CONSERV GENET 2017. [DOI: 10.1007/s10592-017-0995-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Limborg MT, Larson WA, Seeb LW, Seeb JE. Screening of duplicated loci reveals hidden divergence patterns in a complex salmonid genome. Mol Ecol 2017; 26:4509-4522. [DOI: 10.1111/mec.14201] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 04/03/2017] [Accepted: 04/10/2017] [Indexed: 12/31/2022]
Affiliation(s)
- Morten T. Limborg
- School of Aquatic and Fishery Sciences University of Washington Seattle WA USA
| | - Wesley A. Larson
- School of Aquatic and Fishery Sciences University of Washington Seattle WA USA
| | - Lisa W. Seeb
- School of Aquatic and Fishery Sciences University of Washington Seattle WA USA
| | - James E. Seeb
- School of Aquatic and Fishery Sciences University of Washington Seattle WA USA
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Waples RK, Seeb JE, Seeb LW. Congruent population structure across paralogous and nonparalogous loci in Salish Sea chum salmon (Oncorhynchus keta). Mol Ecol 2017; 26:4131-4144. [PMID: 28452089 DOI: 10.1111/mec.14163] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Revised: 04/01/2017] [Accepted: 04/10/2017] [Indexed: 12/19/2022]
Abstract
Whole-genome duplications are major evolutionary events with a lasting impact on genome structure. Duplication events complicate genetic analyses as paralogous sequences are difficult to distinguish; consequently, paralogs are often excluded from studies. The effects of an ancient whole-genome duplication (approximately 88 MYA) are still evident in salmonids through the persistence of numerous paralogous gene sequences and partial tetrasomic inheritance. We use restriction site-associated DNA sequencing on 10 collections of chum salmon from the Salish Sea in the USA and Canada to investigate genetic diversity and population structure in both tetrasomic and rediploidized regions of the genome. We use a pedigree and high-density linkage map to identify paralogous loci and to investigate genetic variation across the genome. By applying multivariate statistical methods, we show that it is possible to characterize paralogous loci and that they display similar patterns of population structure as the diploidized portion of the genome. We find genetic associations with the adaptively important trait of run-timing in both sets of loci. By including paralogous loci in genome scans, we can observe evolutionary signals in genomic regions that have routinely been excluded from population genetic studies in other polyploid-derived species.
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Affiliation(s)
- R K Waples
- School of Aquatic and Fishery Sciences, University of Washington, Seattle, WA, USA
| | - J E Seeb
- School of Aquatic and Fishery Sciences, University of Washington, Seattle, WA, USA
| | - L W Seeb
- School of Aquatic and Fishery Sciences, University of Washington, Seattle, WA, USA
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Ahrens CW, Supple MA, Aitken NC, Cantrill DJ, Borevitz JO, James EA. Genomic diversity guides conservation strategies among rare terrestrial orchid species when taxonomy remains uncertain. ANNALS OF BOTANY 2017; 119:1267-1277. [PMID: 28334284 PMCID: PMC5604565 DOI: 10.1093/aob/mcx022] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2017] [Accepted: 02/12/2017] [Indexed: 05/07/2023]
Abstract
BACKGROUND AND AIMS Species are often used as the unit for conservation, but may not be suitable for species complexes where taxa are difficult to distinguish. Under such circumstances, it may be more appropriate to consider species groups or populations as evolutionarily significant units (ESUs). A population genomic approach was employed to investigate the diversity within and among closely related species to create a more robust, lineage-specific conservation strategy for a nationally endangered terrestrial orchid and its relatives from south-eastern Australia. METHODS Four putative species were sampled from a total of 16 populations in the Victorian Volcanic Plain (VVP) bioregion and one population of a sub-alpine outgroup in south-eastern Australia. Morphological measurements were taken in situ along with leaf material for genotyping by sequencing (GBS) and microsatellite analyses. KEY RESULTS Species could not be differentiated using morphological measurements. Microsatellite and GBS markers confirmed the outgroup as distinct, but only GBS markers provided resolution of population genetic structure. The nationally endangered Diuris basaltica was indistinguishable from two related species ( D. chryseopsis and D. behrii ), while the state-protected D. gregaria showed genomic differentiation. CONCLUSIONS Genomic diversity identified among the four Diuris species suggests that conservation of this taxonomically complex group will be best served by considering them as one ESU rather than separately aligned with species as currently recognized. This approach will maximize evolutionary potential among all species during increased isolation and environmental change. The methods used here can be applied generally to conserve evolutionary processes for groups where taxonomic uncertainty hinders the use of species as conservation units.
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Affiliation(s)
- Collin W. Ahrens
- Royal Botanic Gardens Victoria, Science Division, Melbourne, Victoria 3004, Australia
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW 2751, Australia
- For correspondence. E-mail
| | - Megan A. Supple
- Australian National University, Research School of Biology, Centre of Excellence in Plant Energy Biology, Canberra, ACT 0200, Australia
| | - Nicola C. Aitken
- Australian National University, Research School of Biology, Centre of Excellence in Plant Energy Biology, Canberra, ACT 0200, Australia
| | - David J. Cantrill
- Royal Botanic Gardens Victoria, Science Division, Melbourne, Victoria 3004, Australia
| | - Justin O. Borevitz
- Australian National University, Research School of Biology, Centre of Excellence in Plant Energy Biology, Canberra, ACT 0200, Australia
| | - Elizabeth A. James
- Royal Botanic Gardens Victoria, Science Division, Melbourne, Victoria 3004, Australia
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42
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Christensen KA, Davidson WS. Autopolyploidy genome duplication preserves other ancient genome duplications in Atlantic salmon (Salmo salar). PLoS One 2017; 12:e0173053. [PMID: 28241055 PMCID: PMC5328387 DOI: 10.1371/journal.pone.0173053] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Accepted: 02/14/2017] [Indexed: 11/19/2022] Open
Abstract
Salmonids (e.g. Atlantic salmon, Pacific salmon, and trouts) have a long legacy of genome duplication. In addition to three ancient genome duplications that all teleosts are thought to share, salmonids have had one additional genome duplication. We explored a methodology for untangling these duplications from each other to better understand them in Atlantic salmon. In this methodology, homeologous regions (paralogous/duplicated genomic regions originating from a whole genome duplication) from the most recent genome duplication were assumed to have duplicated genes at greater density and have greater sequence similarity. This assumption was used to differentiate duplicated gene pairs in Atlantic salmon that are either from the most recent genome duplication or from earlier duplications. From a comparison with multiple vertebrate species, it is clear that Atlantic salmon have retained more duplicated genes from ancient genome duplications than other vertebrates--often at higher density in the genome and containing fewer synonymous mutations. It may be that polysomic inheritance is the mechanism responsible for maintaining ancient gene duplicates in salmonids. Polysomic inheritance (when multiple chromosomes pair during meiosis) is thought to be relatively common in salmonids compared to other vertebrate species. These findings illuminate how genome duplications may not only increase the number of duplicated genes, but may also be involved in the maintenance of them from previous genome duplications as well.
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Affiliation(s)
- Kris A. Christensen
- Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada
| | - William S. Davidson
- Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada
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Gillingham MAF, Béchet A, Courtiol A, Rendón-Martos M, Amat JA, Samraoui B, Onmuş O, Sommer S, Cézilly F. Very high MHC Class IIB diversity without spatial differentiation in the mediterranean population of greater Flamingos. BMC Evol Biol 2017; 17:56. [PMID: 28219340 PMCID: PMC5319168 DOI: 10.1186/s12862-017-0905-3] [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: 09/29/2016] [Accepted: 02/06/2017] [Indexed: 02/07/2023] Open
Abstract
Background Selective pressure from pathogens is thought to shape the allelic diversity of major histocompatibility complex (MHC) genes in vertebrates. In particular, both local adaptation to pathogens and gene flow are thought to explain a large part of the intraspecific variation observed in MHC allelic diversity. To date, however, evidence that adaptation to locally prevalent pathogens maintains MHC variation is limited to species with limited dispersal and, hence, reduced gene flow. On the one hand high gene flow can disrupt local adaptation in species with high dispersal rates, on the other hand such species are much more likely to experience spatial variation in pathogen pressure, suggesting that there may be intense pathogen mediated selection pressure operating across breeding sites in panmictic species. Such pathogen mediated selection pressure operating across breeding sites should therefore be sufficient to maintain high MHC diversity in high dispersing species in the absence of local adaptation mechanisms. We used the Greater Flamingo, Phoenicopterus roseus, a long-lived colonial bird showing a homogeneous genetic structure of neutral markers at the scale of the Mediterranean region, to test the prediction that higher MHC allelic diversity with no population structure should occur in large panmictic populations of long-distance dispersing birds than in other resident species. Results We assessed the level of allelic diversity at the MHC Class IIB exon 2 from 116 individuals born in four different breeding colonies of Greater Flamingo in the Mediterranean region. We found one of the highest allelic diversity (109 alleles, 2 loci) of any non-passerine avian species investigated so far relative to the number of individuals and loci genotyped. There was no evidence of population structure between the four major Mediterranean breeding colonies. Conclusion Our results suggest that local adaptation at MHC Class IIB in Greater Flamingos is constrained by high gene flow and high MHC diversity appears to be maintained by population wide pathogen-mediated selection rather than local pathogen-mediated selection. Further understanding of how pathogens vary across space and time will be crucial to further elucidate the mechanisms maintaining MHC diversity in species with large panmictic populations and high dispersal rates. Electronic supplementary material The online version of this article (doi:10.1186/s12862-017-0905-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Mark A F Gillingham
- University of Ulm, Institute of Evolutionary Ecology and Conservation Genomics, Albert-Einstein Allee 11, D-89069, Ulm, Germany. .,Université de Bourgogne, Equipe Ecologie Evolutive, UMR CNRS 6282 Biogéosciences, 6 bd. Gabriel, 21000, Dijon, France. .,Centre de Recherche de la Tour du Valat, Le Sambuc, 13200, Arles, France. .,Leibniz Institute for Zoo and Wildlife Research, Evolutionary Genetics, Alfred-Kowalke-Str. 17, D-10315, Berlin, Germany.
| | - Arnaud Béchet
- Centre de Recherche de la Tour du Valat, Le Sambuc, 13200, Arles, France
| | - Alexandre Courtiol
- Leibniz Institute for Zoo and Wildlife Research, Evolutionary Genetics, Alfred-Kowalke-Str. 17, D-10315, Berlin, Germany.,Berlin Center for Genomics in Biodiversity Research (BeGenDiv), D-14195, Berlin, Germany
| | - Manuel Rendón-Martos
- R.N. Laguna de Fuente de Piedra, Consejería de Medio Ambiente y Ordenación del Territorio, Junta de Andalucía, Apartado 1, E-29520 Fuente de Piedra, (Málaga), Spain
| | - Juan A Amat
- Department of Wetland Ecology, Estación Biológica de Doñana, (EBD-CSIC), calle Américo Vespucio s/n, E-41092, Sevilla, Spain
| | - Boudjéma Samraoui
- Center of Excellence for Research in Biodiversity, King Saud University, Riyadh, Saudi Arabia.,Laboratoire de recherche et de conservation des zones humides, University of Guelma, Guelma, Algeria
| | - Ortaç Onmuş
- Natural History Museum, Faculty of Sciences, Department of Biology, Ege University, Bornova, İzmir, Turkey
| | - Simone Sommer
- University of Ulm, Institute of Evolutionary Ecology and Conservation Genomics, Albert-Einstein Allee 11, D-89069, Ulm, Germany
| | - Frank Cézilly
- Université de Bourgogne, Equipe Ecologie Evolutive, UMR CNRS 6282 Biogéosciences, 6 bd. Gabriel, 21000, Dijon, France.,Institut Universitaire de France, Paris, France
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Doyle JJ, Sherman-Broyles S. Double trouble: taxonomy and definitions of polyploidy. THE NEW PHYTOLOGIST 2017; 213:487-493. [PMID: 28000935 DOI: 10.1111/nph.14276] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Affiliation(s)
- Jeff J Doyle
- Section of Plant Breeding & Genetics, School of Integrated Plant Sciences, Cornell University, Ithaca, NY, 14853, USA
| | - Sue Sherman-Broyles
- Section of Plant Breeding & Genetics, School of Integrated Plant Sciences, Cornell University, Ithaca, NY, 14853, USA
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45
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McKinney GJ, Waples RK, Seeb LW, Seeb JE. Paralogs are revealed by proportion of heterozygotes and deviations in read ratios in genotyping-by-sequencing data from natural populations. Mol Ecol Resour 2016; 17:656-669. [DOI: 10.1111/1755-0998.12613] [Citation(s) in RCA: 127] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 10/06/2016] [Accepted: 10/10/2016] [Indexed: 11/28/2022]
Affiliation(s)
- Garrett J. McKinney
- School of Aquatic and Fishery Sciences; University of Washington; 1122 NE Boat Street, Box 355020 Seattle WA 98195-5020 USA
| | - Ryan K. Waples
- School of Aquatic and Fishery Sciences; University of Washington; 1122 NE Boat Street, Box 355020 Seattle WA 98195-5020 USA
| | - Lisa W. Seeb
- School of Aquatic and Fishery Sciences; University of Washington; 1122 NE Boat Street, Box 355020 Seattle WA 98195-5020 USA
| | - James E. Seeb
- School of Aquatic and Fishery Sciences; University of Washington; 1122 NE Boat Street, Box 355020 Seattle WA 98195-5020 USA
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46
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Dufresne F. Don't throw the baby out with the bathwater: identifying and mapping paralogs in salmonids. Mol Ecol Resour 2016; 16:7-9. [PMID: 26768194 DOI: 10.1111/1755-0998.12477] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Accepted: 10/02/2015] [Indexed: 11/28/2022]
Abstract
Many eukaryotic genomes contain a large fraction of gene duplicates (or paralogs) as a result of ancient or recent whole-genome duplications (Ohno 1970; Jaillon et al. 2004; Kellis et al. 2004). Identifying paralogs with NGS data is a pervasive problem in both ancient polyploids and neopolyploids. Likewise, paralogs are often treated as a nuisance that has to be detected and removed (Everett et al. 2012). In this issue of Molecular Ecology Resources, Waples et al. (2015) show that exclusion might not be necessary and how we may miss out on important genomic information in doing so. They present a novel statistical approach to detect paralogs based on the segregation of RAD loci in haploid offspring and test their method by constructing linkage maps with and without these duplicated loci in chum salmon, Oncorhynchus keta (Fig.1). Their linkage map including the resolved paralogs shows that these are mostly located in the distal regions of several linkage groups. Particularly intriguing is their finding that these homoeologous regions appear impoverished in transposable elements (TE). Given the role that TE play in genome remodelling, it is noteworthy that these elements are of low abundance in regions showing residual tetrasomic inheritance. This raises the question whether re-diploidization is constrained in these regions and whether they might have a role to play in salmonid speciation. This study provides an original approach to identifying duplicated loci in species with a pedigree, as well as providing a dense linkage map for chum salmon, and interesting insights into the retention of gene duplicates in an ancient polyploid.
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Affiliation(s)
- France Dufresne
- Département de biologie, Université du Québec à Rimouski, 300 allée des ursulines, Rimouski, Quebec, Canada, G5L3A1
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47
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Aleza P, Cuenca J, Juárez J, Navarro L, Ollitrault P. Inheritance in doubled-diploid clementine and comparative study with SDR unreduced gametes of diploid clementine. PLANT CELL REPORTS 2016; 35:1573-86. [PMID: 27038940 DOI: 10.1007/s00299-016-1972-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Accepted: 03/21/2016] [Indexed: 05/23/2023]
Abstract
Tetraploid clementine displays mainly tetrasomic inheritance. Genetic structures of 2n SDR and 2 × gametes from DD clementine are complementary and will guides triploids citrus breeding strategies. Triploid breeding is developed worldwide to create new seedless cultivars. Citrus triploid hybrids can be recovered from 2x × 2x sexual hybridizations as a consequence of the formation of unreduced gametes (2n), or from 4x × 2x interploid hybridizations in which tetraploid parents used are most often doubled-diploid (DD). Here we have analyzed the inheritance in doubled-diploid clementine and compared the genetic structures of gametes of DD clementine with SDR unreduced gametes of diploid clementine. Parental heterozygosity restitution (PHR) with DD parents depends on the rate of preferential chromosome pairing and thus the proportion of disomic versus tetrasomic segregations. Doubled-diploid clementine largely exhibited tetrasomic segregation. However, three linkage groups had intermediate segregation and one had a tendency for disomy. Significant doubled reduction rates (DR) rates were observed in six of the nine LGs. Differences of PHR between 2n SDR and 2x DD gametes were highest in the centromeric region and progressively decreased toward the distal regions where they were not significant. Over all markers, PHR was lower (two-thirds) in SDR 2n gametes than in DD-derived diploid gametes. The two strategies appear complementary in terms of genotypic variability. Interploid 4x × 2x hybridization is potentially more efficient for developing new cultivars that are phenotypically closer to the diploid parent of the DD than sexual hybridization through SDR 2n gametes. Conversely, 2x × 2x triploidisation has the potential to produce novel products with characteristics for market segmentation strategies.
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Affiliation(s)
- P Aleza
- Centro de Protección Vegetal y Biotecnología, Instituto Valenciano de Investigaciones Agrarias (IVIA), Ctra. Moncada-Náquera km 4.5, 46113, Moncada, Valencia, Spain
| | - J Cuenca
- Centro de Protección Vegetal y Biotecnología, Instituto Valenciano de Investigaciones Agrarias (IVIA), Ctra. Moncada-Náquera km 4.5, 46113, Moncada, Valencia, Spain
| | - J Juárez
- Centro de Protección Vegetal y Biotecnología, Instituto Valenciano de Investigaciones Agrarias (IVIA), Ctra. Moncada-Náquera km 4.5, 46113, Moncada, Valencia, Spain
| | - L Navarro
- Centro de Protección Vegetal y Biotecnología, Instituto Valenciano de Investigaciones Agrarias (IVIA), Ctra. Moncada-Náquera km 4.5, 46113, Moncada, Valencia, Spain.
| | - P Ollitrault
- Centro de Protección Vegetal y Biotecnología, Instituto Valenciano de Investigaciones Agrarias (IVIA), Ctra. Moncada-Náquera km 4.5, 46113, Moncada, Valencia, Spain.
- UMR AGAP, Centre de coopération Internationale en Recherche Agronomique pour le Développement (CIRAD), Station de Roujol, 97170, Petit-Bourg, Guadeloupe.
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Benestan LM, Ferchaud A, Hohenlohe PA, Garner BA, Naylor GJP, Baums IB, Schwartz MK, Kelley JL, Luikart G. Conservation genomics of natural and managed populations: building a conceptual and practical framework. Mol Ecol 2016; 25:2967-77. [DOI: 10.1111/mec.13647] [Citation(s) in RCA: 111] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Revised: 03/12/2016] [Accepted: 04/06/2016] [Indexed: 12/18/2022]
Affiliation(s)
- Laura Marilyn Benestan
- Departement de Biologie Institut de Biologie Intégrative et des Systèmes (IBIS) Université Laval Québec G1V 0A6 Canada
| | - Anne‐Laure Ferchaud
- Departement de Biologie Institut de Biologie Intégrative et des Systèmes (IBIS) Université Laval Québec G1V 0A6 Canada
| | - Paul A. Hohenlohe
- Institute for Bioinformatics and Evolutionary Studies University of Idaho Moscow ID 83844 USA
| | - Brittany A. Garner
- Flathead Lake Biological Station Fish and Wildlife Genomic Group Division of Biological Science University of Montana Missoula MT 59812 USA
- Wildlife Program Fish and Wildlife Genomic Group College of Forestry and Conservation University of Montana Missoula MT 59812 USA
| | - Gavin J. P. Naylor
- Hollings Marine Lab College of Charleston and Medical University of South Carolina 331 Fort Johnson Rd. Charleston SC 29412 USA
| | - Iliana Brigitta Baums
- Department of Biology Pennsylvania State University 208 Mueller Lab University Park PA 1680 USA
| | - Michael K. Schwartz
- USDA Forest Service National Genomics Center for Wildlife and Fish Conservation 800 E. Beckwith Ave. Missoula MT 59801 USA
| | - Joanna L. Kelley
- School of Biological Sciences Washington State University Pullman WA 99164 USA
| | - Gordon Luikart
- Flathead Lake Biological Station Fish and Wildlife Genomic Group Division of Biological Science University of Montana Missoula MT 59812 USA
- Wildlife Program Fish and Wildlife Genomic Group College of Forestry and Conservation University of Montana Missoula MT 59812 USA
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Balao F, Tannhäuser M, Lorenzo MT, Hedrén M, Paun O. Genetic differentiation and admixture between sibling allopolyploids in the Dactylorhiza majalis complex. Heredity (Edinb) 2016; 116:351-61. [PMID: 26604189 PMCID: PMC4787024 DOI: 10.1038/hdy.2015.98] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Revised: 10/17/2015] [Accepted: 10/20/2015] [Indexed: 12/24/2022] Open
Abstract
Allopolyploidization often happens recurrently, but the evolutionary significance of its iterative nature is not yet fully understood. Of particular interest are the gene flow dynamics and the mechanisms that allow young sibling polyploids to remain distinct while sharing the same ploidy, heritage and overlapping distribution areas. By using eight highly variable nuclear microsatellites, newly reported here, we investigate the patterns of divergence and gene flow between 386 polyploid and 42 diploid individuals, representing the sibling allopolyploids Dactylorhiza majalis s.s. and D. traunsteineri s.l. and their parents at localities across Europe. We make use in our inference of the distinct distribution ranges of the polyploids, including areas in which they are sympatric (that is, the Alps) or allopatric (for example, Pyrenees with D. majalis only and Britain with D. traunsteineri only). Our results show a phylogeographic signal, but no clear genetic differentiation between the allopolyploids, despite the visible phenotypic divergence between them. The results indicate that gene flow between sibling Dactylorhiza allopolyploids is frequent in sympatry, with potential implications for the genetic patterns across their entire distribution range. Limited interploidal introgression is also evidenced, in particular between D. incarnata and D. traunsteineri. Altogether the allopolyploid genomes appear to be porous for introgression from related diploids and polyploids. We conclude that the observed phenotypic divergence between D. majalis and D. traunsteineri is maintained by strong divergent selection on specific genomic areas with strong penetrance, but which are short enough to remain undetected by genotyping dispersed neutral markers.
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Affiliation(s)
- F Balao
- Department of Botany and Biodiversity Research, University of Vienna, Vienna, Austria
| | - M Tannhäuser
- Department of Botany and Biodiversity Research, University of Vienna, Vienna, Austria
| | - M T Lorenzo
- Department of Botany and Biodiversity Research, University of Vienna, Vienna, Austria
| | - M Hedrén
- Department of Biology, Lund University, Lund, Sweden
| | - O Paun
- Department of Botany and Biodiversity Research, University of Vienna, Vienna, Austria
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50
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Rosche C, Durka W, Hensen I, Mráz P, Hartmann M, Müller-Schärer H, Lachmuth S. The population genetics of the fundamental cytotype-shift in invasive Centaurea stoebe s.l.: genetic diversity, genetic differentiation and small-scale genetic structure differ between cytotypes but not between ranges. Biol Invasions 2016. [DOI: 10.1007/s10530-016-1133-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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