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Christenhusz MJM, Pannell JR, Twyford AD. The genome sequence of the Annual Mercury, Mercurialis annua L., 1753 (Euphorbiaceae). Wellcome Open Res 2024; 9:102. [PMID: 38854694 PMCID: PMC11157195 DOI: 10.12688/wellcomeopenres.21004.1] [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] [Accepted: 02/02/2024] [Indexed: 06/11/2024] Open
Abstract
We present a genome assembly from a diploid female Mercurialis annua (the Annual Mercury; Tracheophyta; Magnoliopsida; Malpighiales; Euphorbiaceae). The genome sequence is 453.2 megabases in span. Most of the assembly is scaffolded into 8 chromosomal pseudomolecules, including the X chromosome. The organelle genomes have also been assembled, and the mitochondrial genome is 435.28 kilobases in length, while the plastid genome is 169.65 kilobases in length.
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Affiliation(s)
| | - John R. Pannell
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
| | - Alex D. Twyford
- The University of Edinburgh, Edinburgh, Scotland, UK
- Royal Botanic Garden Edinburgh, Edinburgh, Scotland, UK
| | - Royal Botanic Gardens Kew Genome Acquisition Lab
- Royal Botanic Gardens Kew, Richmond, England, UK
- Curtin University, Perth, Western Australia, Australia
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
- The University of Edinburgh, Edinburgh, Scotland, UK
- Royal Botanic Garden Edinburgh, Edinburgh, Scotland, UK
| | - Plant Genome Sizing collective
- Royal Botanic Gardens Kew, Richmond, England, UK
- Curtin University, Perth, Western Australia, Australia
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
- The University of Edinburgh, Edinburgh, Scotland, UK
- Royal Botanic Garden Edinburgh, Edinburgh, Scotland, UK
| | - Darwin Tree of Life Barcoding collective
- Royal Botanic Gardens Kew, Richmond, England, UK
- Curtin University, Perth, Western Australia, Australia
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
- The University of Edinburgh, Edinburgh, Scotland, UK
- Royal Botanic Garden Edinburgh, Edinburgh, Scotland, UK
| | - Wellcome Sanger Institute Tree of Life programme
- Royal Botanic Gardens Kew, Richmond, England, UK
- Curtin University, Perth, Western Australia, Australia
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
- The University of Edinburgh, Edinburgh, Scotland, UK
- Royal Botanic Garden Edinburgh, Edinburgh, Scotland, UK
| | - Wellcome Sanger Institute Scientific Operations: DNA Pipelines collective
- Royal Botanic Gardens Kew, Richmond, England, UK
- Curtin University, Perth, Western Australia, Australia
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
- The University of Edinburgh, Edinburgh, Scotland, UK
- Royal Botanic Garden Edinburgh, Edinburgh, Scotland, UK
| | - Tree of Life Core Informatics collective
- Royal Botanic Gardens Kew, Richmond, England, UK
- Curtin University, Perth, Western Australia, Australia
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
- The University of Edinburgh, Edinburgh, Scotland, UK
- Royal Botanic Garden Edinburgh, Edinburgh, Scotland, UK
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2
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Guichard A, Legeai F, Tagu D, Lemaitre C. MTG-Link: leveraging barcode information from linked-reads to assemble specific loci. BMC Bioinformatics 2023; 24:284. [PMID: 37452278 PMCID: PMC10347852 DOI: 10.1186/s12859-023-05395-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 06/21/2023] [Indexed: 07/18/2023] Open
Abstract
BACKGROUND Local assembly with short and long reads has proven to be very useful in many applications: reconstruction of the sequence of a locus of interest, gap-filling in draft assemblies, as well as alternative allele reconstruction of large Structural Variants. Whereas linked-read technologies have a great potential to assemble specific loci as they provide long-range information while maintaining the power and accuracy of short-read sequencing, there is a lack of local assembly tools for linked-read data. RESULTS We present MTG-Link, a novel local assembly tool dedicated to linked-reads. The originality of the method lies in its read subsampling step which takes advantage of the barcode information contained in linked-reads mapped in flanking regions. We validated our approach on several datasets from different linked-read technologies. We show that MTG-Link is able to assemble successfully large sequences, up to dozens of Kb. We also demonstrate that the read subsampling step of MTG-Link considerably improves the local assembly of specific loci compared to other existing short-read local assembly tools. Furthermore, MTG-Link was able to fully characterize large insertion variants and deletion breakpoints in a human genome and to reconstruct dark regions in clinically-relevant human genes. It also improved the contiguity of a 1.3 Mb locus of biological interest in several individual genomes of the mimetic butterfly Heliconius numata. CONCLUSIONS MTG-Link is an efficient local assembly tool designed for different linked-read sequencing technologies. MTG-Link source code is available at https://github.com/anne-gcd/MTG-Link and as a Bioconda package.
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Affiliation(s)
- Anne Guichard
- IGEPP, INRAE, Institut Agro, Univ Rennes, 35653, Le Rheu, France.
- Univ Rennes, Inria, CNRS, IRISA, 35000, Rennes, France.
| | - Fabrice Legeai
- IGEPP, INRAE, Institut Agro, Univ Rennes, 35653, Le Rheu, France
- Univ Rennes, Inria, CNRS, IRISA, 35000, Rennes, France
| | - Denis Tagu
- IGEPP, INRAE, Institut Agro, Univ Rennes, 35653, Le Rheu, France
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3
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Raiyemo DA, Bobadilla LK, Tranel PJ. Genomic profiling of dioecious Amaranthus species provides novel insights into species relatedness and sex genes. BMC Biol 2023; 21:37. [PMID: 36804015 PMCID: PMC9940365 DOI: 10.1186/s12915-023-01539-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Accepted: 02/08/2023] [Indexed: 02/21/2023] Open
Abstract
BACKGROUND Amaranthus L. is a diverse genus consisting of domesticated, weedy, and non-invasive species distributed around the world. Nine species are dioecious, of which Amaranthus palmeri S. Watson and Amaranthus tuberculatus (Moq.) J.D. Sauer are troublesome weeds of agronomic crops in the USA and elsewhere. Shallow relationships among the dioecious Amaranthus species and the conservation of candidate genes within previously identified A. palmeri and A. tuberculatus male-specific regions of the Y (MSYs) in other dioecious species are poorly understood. In this study, seven genomes of dioecious amaranths were obtained by paired-end short-read sequencing and combined with short reads of seventeen species in the family Amaranthaceae from NCBI database. The species were phylogenomically analyzed to understand their relatedness. Genome characteristics for the dioecious species were evaluated and coverage analysis was used to investigate the conservation of sequences within the MSY regions. RESULTS We provide genome size, heterozygosity, and ploidy level inference for seven newly sequenced dioecious Amaranthus species and two additional dioecious species from the NCBI database. We report a pattern of transposable element proliferation in the species, in which seven species had more Ty3 elements than copia elements while A. palmeri and A. watsonii had more copia elements than Ty3 elements, similar to the TE pattern in some monoecious amaranths. Using a Mash-based phylogenomic analysis, we accurately recovered taxonomic relationships among the dioecious Amaranthus species that were previously identified based on comparative morphology. Coverage analysis revealed eleven candidate gene models within the A. palmeri MSY region with male-enriched coverages, as well as regions on scaffold 19 with female-enriched coverage, based on A. watsonii read alignments. A previously reported FLOWERING LOCUS T (FT) within A. tuberculatus MSY contig was also found to exhibit male-enriched coverages for three species closely related to A. tuberculatus but not for A. watsonii reads. Additional characterization of the A. palmeri MSY region revealed that 78% of the region is made of repetitive elements, typical of a sex determination region with reduced recombination. CONCLUSIONS The results of this study further increase our understanding of the relationships among the dioecious species of the Amaranthus genus as well as revealed genes with potential roles in sex function in the species.
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Affiliation(s)
- Damilola A Raiyemo
- Department of Crop Sciences, University of Illinois, Urbana, IL, 61801, USA
| | - Lucas K Bobadilla
- Department of Crop Sciences, University of Illinois, Urbana, IL, 61801, USA
| | - Patrick J Tranel
- Department of Crop Sciences, University of Illinois, Urbana, IL, 61801, USA.
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4
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Gerchen JF, Veltsos P, Pannell JR. Recurrent allopolyploidization, Y-chromosome introgression and the evolution of sexual systems in the plant genus Mercurialis. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210224. [PMID: 35306889 PMCID: PMC8935306 DOI: 10.1098/rstb.2021.0224] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The plant genus Mercurialis includes dioecious, monoecious and androdioecious species (where males coexist with hermaphrodites). Its diversification involved reticulate evolution via hybridization and polyploidization. The Y chromosome of the diploid species Mercurialis annua shows only mild signs of degeneration. We used sequence variation at a Y-linked locus in several species and at multiple autosomal and pseudoautosomal loci to investigate the origin and evolution of the Y chromosome across the genus. Our study provides evidence for further cases of allopolyploid speciation. It also reveals that all lineages with separate sexes (with one possible exception) share the same ancestral Y chromosome. Surprisingly, males in androdioecious populations of hexaploid M. annua carry a Y chromosome that is not derived from either of its two putative progenitor lineages but from a more distantly related perennial dioecious lineage via introgression. These results throw new light on the evolution of sexual systems and polyploidy in Mercurialis and secure it as a promising model for further study of plant sex chromosomes. This article is part of the theme issue 'Sex determination and sex chromosome evolution in land plants'.
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Affiliation(s)
- J F Gerchen
- Department of Ecology and Evolution, University of Lausanne, 1015 Lausanne, Switzerland
| | - P Veltsos
- Department of Ecology and Evolution, University of Lausanne, 1015 Lausanne, Switzerland
| | - J R Pannell
- Department of Ecology and Evolution, University of Lausanne, 1015 Lausanne, Switzerland
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5
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Villamil N, Li X, Seddon E, Pannell JR. Simulated herbivory enhances leaky sex expression in the dioecious herb Mercurialis annua. ANNALS OF BOTANY 2022; 129:79-86. [PMID: 34668537 PMCID: PMC8829902 DOI: 10.1093/aob/mcab129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Accepted: 10/01/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND AND AIMS Plant reproductive traits are widely understood to be responsive to the selective pressures exerted by pollinators, but there is also increasing evidence for an important role for antagonists such as herbivores in shaping these traits. Many dioecious species show leaky sex expression, with males and females occasionally producing flowers of the opposite sex. Here, we asked to what extent leakiness in sex expression in Mercurialis annua (Euphorbiaceae) might also be plastically responsive to simulated herbivory. This is important because enhanced leakiness in dioecious populations could lead to a shift in both the mating system and in the conditions for transitions between combined and separate sexes. METHODS We examined the effect of simulated herbivory on the sexual expression of males and females of M. annua in two experiments in which different levels of simulated herbivory led to enhanced leakiness in both sexes. KEY RESULTS We showed that leaky sex expression in both males and females of the wind-pollinated dioecious herb M. annua is enhanced in response to simulated herbivory, increasing the probability for and the degree of leakiness in both sexes. We also found that leakiness was greater in larger females but not in larger males. CONCLUSIONS We discuss hypotheses for a possible functional link between herbivory and leaky sex expression, and consider what simulated herbivory-induced leakiness might imply for the evolutionary ecology of plant reproductive systems, especially the breakdown of dioecy and the evolution of hermaphroditism.
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Affiliation(s)
- Nora Villamil
- Department of Ecology and Evolution, Université de Lausanne, Switzerland
| | - Xinji Li
- Department of Ecology and Evolution, Université de Lausanne, Switzerland
| | - Emily Seddon
- Department of Ecology and Evolution, Université de Lausanne, Switzerland
- Vegetation Ecologist, NatureServe, Boulder, CO 80301, USA
| | - John R Pannell
- Department of Ecology and Evolution, Université de Lausanne, Switzerland
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The rapid dissolution of dioecy by experimental evolution. Curr Biol 2021; 31:1277-1283.e5. [PMID: 33472050 DOI: 10.1016/j.cub.2020.12.028] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 12/10/2020] [Accepted: 12/18/2020] [Indexed: 11/20/2022]
Abstract
Evolutionary transitions from hermaphroditism to dioecy have been common in flowering plants,1,2 but recent analysis also points to frequent reversions from dioecy to hermaphroditism.2-4 Here, we use experimental evolution to expose a mechanism for such reversions, validating an explanation for the scattered phylogenetic distribution of dioecy. We removed males from dioecious populations of the wind-pollinated plant Mercurialis annua and allowed natural selection to act on the remaining females that occasionally produced male flowers; such "leaky" sex expression is common in both males and females of dioecious plants.5 Over the course of four generations, females evolved a 23-fold increase in average male flower production. This phenotypic masculinization of females coincided with the evolution of partial self-fertilization, high average seed set in the continued absence of males, and a capacity to sire progeny when males were re-introduced into their populations. Our study thus validates a mechanism for the rapid dissolution of dioecy and the evolution of functional hermaphroditism under conditions that may frequently occur during periods of low population density, repeated colonization, or range expansion.6,7 Our results illustrate the power of natural selection, acting in replicated experimental populations, to bring about transitions in the mating behavior of plants.
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7
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Jesionek W, Bodláková M, Kubát Z, Čegan R, Vyskot B, Vrána J, Šafář J, Puterova J, Hobza R. Fundamentally different repetitive element composition of sex chromosomes in Rumex acetosa. ANNALS OF BOTANY 2021; 127:33-47. [PMID: 32902599 PMCID: PMC7750719 DOI: 10.1093/aob/mcaa160] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Accepted: 08/31/2020] [Indexed: 05/10/2023]
Abstract
BACKGROUND AND AIMS Dioecious species with well-established sex chromosomes are rare in the plant kingdom. Most sex chromosomes increase in size but no comprehensive analysis of the kind of sequences that drive this expansion has been presented. Here we analyse sex chromosome structure in common sorrel (Rumex acetosa), a dioecious plant with XY1Y2 sex determination, and we provide the first chromosome-specific repeatome analysis for a plant species possessing sex chromosomes. METHODS We flow-sorted and separately sequenced sex chromosomes and autosomes in R. acetosa using the two-dimensional fluorescence in situ hybridization in suspension (FISHIS) method and Illumina sequencing. We identified and quantified individual repeats using RepeatExplorer, Tandem Repeat Finder and the Tandem Repeats Analysis Program. We employed fluorescence in situ hybridization (FISH) to analyse the chromosomal localization of satellites and transposons. KEY RESULTS We identified a number of novel satellites, which have, in a fashion similar to previously known satellites, significantly expanded on the Y chromosome but not as much on the X or on autosomes. Additionally, the size increase of Y chromosomes is caused by non-long terminal repeat (LTR) and LTR retrotransposons, while only the latter contribute to the enlargement of the X chromosome. However, the X chromosome is populated by different LTR retrotransposon lineages than those on Y chromosomes. CONCLUSIONS The X and Y chromosomes have significantly diverged in terms of repeat composition. The lack of recombination probably contributed to the expansion of diverse satellites and microsatellites and faster fixation of newly inserted transposable elements (TEs) on the Y chromosomes. In addition, the X and Y chromosomes, despite similar total counts of TEs, differ significantly in the representation of individual TE lineages, which indicates that transposons proliferate preferentially in either the paternal or the maternal lineage.
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Affiliation(s)
- Wojciech Jesionek
- Department of Plant Developmental Genetics, The Czech Academy of Sciences, Institute of Biophysics, Královopolská, Brno, Czech Republic
- Department of Experimental Biology, Faculty of Science, Masaryk University, Kamenice, Brno, Czech Republic
- For correspondence. E-mail: or
| | - Markéta Bodláková
- Department of Plant Developmental Genetics, The Czech Academy of Sciences, Institute of Biophysics, Královopolská, Brno, Czech Republic
| | - Zdeněk Kubát
- Department of Plant Developmental Genetics, The Czech Academy of Sciences, Institute of Biophysics, Královopolská, Brno, Czech Republic
| | - Radim Čegan
- Department of Plant Developmental Genetics, The Czech Academy of Sciences, Institute of Biophysics, Královopolská, Brno, Czech Republic
| | - Boris Vyskot
- Department of Plant Developmental Genetics, The Czech Academy of Sciences, Institute of Biophysics, Královopolská, Brno, Czech Republic
| | - Jan Vrána
- Institute of Experimental Botany, Centre of the Region Haná for Biotechnological and Agricultural Research, Šlechtitelů, Olomouc-Holice, Czech Republic
| | - Jan Šafář
- Institute of Experimental Botany, Centre of the Region Haná for Biotechnological and Agricultural Research, Šlechtitelů, Olomouc-Holice, Czech Republic
| | - Janka Puterova
- Department of Plant Developmental Genetics, The Czech Academy of Sciences, Institute of Biophysics, Královopolská, Brno, Czech Republic
- Brno University of Technology, Faculty of Information Technology, Centre of Excellence IT4Innovations, Bozetechova, Brno, Czech Republic
| | - Roman Hobza
- Department of Plant Developmental Genetics, The Czech Academy of Sciences, Institute of Biophysics, Královopolská, Brno, Czech Republic
- For correspondence. E-mail: or
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Cossard GG, Pannell JR. Enhanced leaky sex expression in response to pollen limitation in the dioecious plant Mercurialis annua. J Evol Biol 2020; 34:416-422. [PMID: 33098734 PMCID: PMC7984330 DOI: 10.1111/jeb.13720] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 09/23/2020] [Accepted: 09/25/2020] [Indexed: 02/02/2023]
Abstract
In dioecious plants, males and females frequently show ‘leaky’ sex expression, with individuals occasionally producing flowers of the opposite sex. This leaky sex expression may have enabled the colonization of oceanic islands by dioecious plant species, and it is likely to represent the sort of variation upon which selection acts to bring about evolutionary transitions from dioecy to hermaphroditism. Although leakiness is commonly reported for dioecious species, it is not known whether it has plastic component. The question is interesting because males or females with an ability to enhance their leakiness plastically in the absence of mates would have an advantage of being able to produce progeny by self‐fertilization. Here, we demonstrate that leaky sex expression in the wind‐pollinated dioecious herb Mercurialis annua is plastically responsive to its mating context. We compared experimental populations of females growing either with or without males. Females growing in the absence of males were leakier in their sex expression than controls growing with males, producing more than twice as many male flowers. Our results thus provide a striking instance of plasticity in the reproductive behaviour of plants that is likely adaptive. We consider how females might sense their mating environment as a function of pollen availability, and we discuss possible constraints on the evolution of plasticity in sex expression when the environmental signals that individuals receive are unreliable.
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Affiliation(s)
- Guillaume G Cossard
- Department of Ecology and Evolution, Biophore Building, University of Lausanne, Lausanne, Switzerland
| | - John R Pannell
- Department of Ecology and Evolution, Biophore Building, University of Lausanne, Lausanne, Switzerland
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Baránková S, Pascual-Díaz JP, Sultana N, Alonso-Lifante MP, Balant M, Barros K, D'Ambrosio U, Malinská H, Peska V, Pérez Lorenzo I, Kovařík A, Vyskot B, Janoušek B, Garcia S. Sex-chrom, a database on plant sex chromosomes. THE NEW PHYTOLOGIST 2020; 227:1594-1604. [PMID: 32357248 DOI: 10.1111/nph.16635] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 04/25/2020] [Indexed: 05/15/2023]
Affiliation(s)
- Simona Baránková
- Institut Botanic de Barcelona (IBB-CSIC, Ajuntament de Barcelona), Passeig del Migdia s/n, 08038, Barcelona, Catalonia, Spain
- Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 612 65, Brno, Czech Republic
| | - Joan Pere Pascual-Díaz
- Institut Botanic de Barcelona (IBB-CSIC, Ajuntament de Barcelona), Passeig del Migdia s/n, 08038, Barcelona, Catalonia, Spain
| | - Nusrat Sultana
- Institut Botanic de Barcelona (IBB-CSIC, Ajuntament de Barcelona), Passeig del Migdia s/n, 08038, Barcelona, Catalonia, Spain
- Department of Botany, Faculty of Life and Earth Sciences, Jagannath University, Dhaka, 1100, Bangladesh
| | - Maria Pilar Alonso-Lifante
- Institut Botanic de Barcelona (IBB-CSIC, Ajuntament de Barcelona), Passeig del Migdia s/n, 08038, Barcelona, Catalonia, Spain
| | - Manica Balant
- Institut Botanic de Barcelona (IBB-CSIC, Ajuntament de Barcelona), Passeig del Migdia s/n, 08038, Barcelona, Catalonia, Spain
| | - Karina Barros
- Institut Botanic de Barcelona (IBB-CSIC, Ajuntament de Barcelona), Passeig del Migdia s/n, 08038, Barcelona, Catalonia, Spain
| | - Ugo D'Ambrosio
- Institut Botanic de Barcelona (IBB-CSIC, Ajuntament de Barcelona), Passeig del Migdia s/n, 08038, Barcelona, Catalonia, Spain
| | - Hana Malinská
- Institut Botanic de Barcelona (IBB-CSIC, Ajuntament de Barcelona), Passeig del Migdia s/n, 08038, Barcelona, Catalonia, Spain
- Department of Biology, Faculty of Science, Jan Evangelista Purkyně University in Ústí nad Labem, 400 96, Ústí nad Labem, Czech Republic
| | - Vratislav Peska
- Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 612 65, Brno, Czech Republic
| | - Iván Pérez Lorenzo
- Institut Botanic de Barcelona (IBB-CSIC, Ajuntament de Barcelona), Passeig del Migdia s/n, 08038, Barcelona, Catalonia, Spain
| | - Aleš Kovařík
- Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 612 65, Brno, Czech Republic
| | - Boris Vyskot
- Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 612 65, Brno, Czech Republic
| | - Bohuslav Janoušek
- Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 612 65, Brno, Czech Republic
| | - Sònia Garcia
- Institut Botanic de Barcelona (IBB-CSIC, Ajuntament de Barcelona), Passeig del Migdia s/n, 08038, Barcelona, Catalonia, Spain
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10
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Almeida P, Proux-Wera E, Churcher A, Soler L, Dainat J, Pucholt P, Nordlund J, Martin T, Rönnberg-Wästljung AC, Nystedt B, Berlin S, Mank JE. Genome assembly of the basket willow, Salix viminalis, reveals earliest stages of sex chromosome expansion. BMC Biol 2020; 18:78. [PMID: 32605573 PMCID: PMC7329446 DOI: 10.1186/s12915-020-00808-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 06/11/2020] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Sex chromosomes have evolved independently multiple times in eukaryotes and are therefore considered a prime example of convergent genome evolution. Sex chromosomes are known to emerge after recombination is halted between a homologous pair of chromosomes, and this leads to a range of non-adaptive modifications causing gradual degeneration and gene loss on the sex-limited chromosome. However, the proximal causes of recombination suppression and the pace at which degeneration subsequently occurs remain unclear. RESULTS Here, we use long- and short-read single-molecule sequencing approaches to assemble and annotate a draft genome of the basket willow, Salix viminalis, a species with a female heterogametic system at the earliest stages of sex chromosome emergence. Our single-molecule approach allowed us to phase the emerging Z and W haplotypes in a female, and we detected very low levels of Z/W single-nucleotide divergence in the non-recombining region. Linked-read sequencing of the same female and an additional male (ZZ) revealed the presence of two evolutionary strata supported by both divergence between the Z and W haplotypes and by haplotype phylogenetic trees. Gene order is still largely conserved between the Z and W homologs, although the W-linked region contains genes involved in cytokinin signaling regulation that are not syntenic with the Z homolog. Furthermore, we find no support across multiple lines of evidence for inversions, which have long been assumed to halt recombination between the sex chromosomes. CONCLUSIONS Our data suggest that selection against recombination is a more gradual process at the earliest stages of sex chromosome formation than would be expected from an inversion and may result instead from the accumulation of transposable elements. Our results present a cohesive understanding of the earliest genomic consequences of recombination suppression as well as valuable insights into the initial stages of sex chromosome formation and regulation of sex differentiation.
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Affiliation(s)
- Pedro Almeida
- Department of Genetics, Evolution & Environment, University College London, London, UK.
| | - Estelle Proux-Wera
- Department of Biochemistry and Biophysics, National Bioinformatics Infrastructure Sweden, Science for Life Laboratory, Stockholm University, Stockholm, Sweden
| | - Allison Churcher
- Department of Molecular Biology, National Bioinformatics Infrastructure Sweden, Science for Life Laboratory, Umeå University, Umeå, Sweden
| | - Lucile Soler
- Department of Medical Biochemistry and Microbiology, National Bioinformatics Infrastructure Sweden, Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Jacques Dainat
- Department of Medical Biochemistry and Microbiology, National Bioinformatics Infrastructure Sweden, Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Pascal Pucholt
- Department of Medical Sciences, Section of Rheumatology, Uppsala University, Uppsala, Sweden
- Department of Plant Biology, Uppsala BioCenter, Linnean Centre for Plant Biology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Jessica Nordlund
- Department of Medical Sciences, National Genomics Infrastructure, Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Tom Martin
- Department of Medical Sciences, Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Ann-Christin Rönnberg-Wästljung
- Department of Plant Biology, Uppsala BioCenter, Linnean Centre for Plant Biology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Björn Nystedt
- Department of Cell and Molecular Biology, National Bioinformatics Infrastructure Sweden, Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Sofia Berlin
- Department of Plant Biology, Uppsala BioCenter, Linnean Centre for Plant Biology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Judith E Mank
- Department of Genetics, Evolution & Environment, University College London, London, UK
- Department of Zoology and Biodiversity Research Centre, University of British Columbia, Vancouver, Canada
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11
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Almeida P, Proux-Wera E, Churcher A, Soler L, Dainat J, Pucholt P, Nordlund J, Martin T, Rönnberg-Wästljung AC, Nystedt B, Berlin S, Mank JE. Genome assembly of the basket willow, Salix viminalis, reveals earliest stages of sex chromosome expansion. BMC Biol 2020. [PMID: 32605573 DOI: 10.1101/589804v1.full] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/23/2023] Open
Abstract
BACKGROUND Sex chromosomes have evolved independently multiple times in eukaryotes and are therefore considered a prime example of convergent genome evolution. Sex chromosomes are known to emerge after recombination is halted between a homologous pair of chromosomes, and this leads to a range of non-adaptive modifications causing gradual degeneration and gene loss on the sex-limited chromosome. However, the proximal causes of recombination suppression and the pace at which degeneration subsequently occurs remain unclear. RESULTS Here, we use long- and short-read single-molecule sequencing approaches to assemble and annotate a draft genome of the basket willow, Salix viminalis, a species with a female heterogametic system at the earliest stages of sex chromosome emergence. Our single-molecule approach allowed us to phase the emerging Z and W haplotypes in a female, and we detected very low levels of Z/W single-nucleotide divergence in the non-recombining region. Linked-read sequencing of the same female and an additional male (ZZ) revealed the presence of two evolutionary strata supported by both divergence between the Z and W haplotypes and by haplotype phylogenetic trees. Gene order is still largely conserved between the Z and W homologs, although the W-linked region contains genes involved in cytokinin signaling regulation that are not syntenic with the Z homolog. Furthermore, we find no support across multiple lines of evidence for inversions, which have long been assumed to halt recombination between the sex chromosomes. CONCLUSIONS Our data suggest that selection against recombination is a more gradual process at the earliest stages of sex chromosome formation than would be expected from an inversion and may result instead from the accumulation of transposable elements. Our results present a cohesive understanding of the earliest genomic consequences of recombination suppression as well as valuable insights into the initial stages of sex chromosome formation and regulation of sex differentiation.
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Affiliation(s)
- Pedro Almeida
- Department of Genetics, Evolution & Environment, University College London, London, UK.
| | - Estelle Proux-Wera
- Department of Biochemistry and Biophysics, National Bioinformatics Infrastructure Sweden, Science for Life Laboratory, Stockholm University, Stockholm, Sweden
| | - Allison Churcher
- Department of Molecular Biology, National Bioinformatics Infrastructure Sweden, Science for Life Laboratory, Umeå University, Umeå, Sweden
| | - Lucile Soler
- Department of Medical Biochemistry and Microbiology, National Bioinformatics Infrastructure Sweden, Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Jacques Dainat
- Department of Medical Biochemistry and Microbiology, National Bioinformatics Infrastructure Sweden, Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Pascal Pucholt
- Department of Medical Sciences, Section of Rheumatology, Uppsala University, Uppsala, Sweden
- Department of Plant Biology, Uppsala BioCenter, Linnean Centre for Plant Biology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Jessica Nordlund
- Department of Medical Sciences, National Genomics Infrastructure, Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Tom Martin
- Department of Medical Sciences, Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Ann-Christin Rönnberg-Wästljung
- Department of Plant Biology, Uppsala BioCenter, Linnean Centre for Plant Biology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Björn Nystedt
- Department of Cell and Molecular Biology, National Bioinformatics Infrastructure Sweden, Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Sofia Berlin
- Department of Plant Biology, Uppsala BioCenter, Linnean Centre for Plant Biology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Judith E Mank
- Department of Genetics, Evolution & Environment, University College London, London, UK
- Department of Zoology and Biodiversity Research Centre, University of British Columbia, Vancouver, Canada
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12
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Khadka J, Yadav NS, Guy M, Grafi G, Golan-Goldhirsh A. Epigenetic aspects of floral homeotic genes in relation to sexual dimorphism in the dioecious plant Mercurialis annua. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:6245-6259. [PMID: 31504768 PMCID: PMC6859717 DOI: 10.1093/jxb/erz379] [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: 03/12/2019] [Accepted: 08/08/2019] [Indexed: 05/26/2023]
Abstract
In plants, dioecy characterizes species that carry male and female flowers on separate plants and it occurs in about 6% of angiosperms; however, the molecular mechanisms that underlie dioecy are essentially unknown. The ability for sex-reversal by hormone application raises the hypothesis that the genes required for the expression of both sexes are potentially functional but are regulated by epigenetic means. In this study, proteomic analysis of nuclear proteins isolated from flower buds of females, males, and feminized males of the dioecious plant Mercurialis annua revealed differential expression of nuclear proteins that are implicated in chromatin structure and function, including floral homeotic proteins. Focusing on floral genes, we found that class B genes were mainly expressed in male flowers, while class D genes, as well as SUPERMAN-like genes, were mainly expressed in female flowers. Cytokinin-induced feminization of male plants was associated with down-regulation of male-specific genes concomitantly with up-regulation of female-specific genes. No correlation was found between the expression of class B and D genes and the changes in DNA methylation or chromatin conformation of these genes. Thus, we could not confirm DNA methylation or chromatin conformation of floral genes to be the major determinant regulating sexual dimorphisms. Instead, determination of sex in M. annua might be controlled upstream of floral genes by one or more sex-specific factors that affect hormonal homeostasis. A comprehensive model is proposed for sex-determination in M. annua.
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Affiliation(s)
- Janardan Khadka
- French Associates Institute for Agriculture and Biotechnology of Drylands, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshet Ben Gurion, Israel
| | | | - Micha Guy
- French Associates Institute for Agriculture and Biotechnology of Drylands, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshet Ben Gurion, Israel
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13
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Charlesworth D. Young sex chromosomes in plants and animals. THE NEW PHYTOLOGIST 2019; 224:1095-1107. [PMID: 31222890 DOI: 10.1111/nph.16002] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 06/10/2019] [Indexed: 05/28/2023]
Abstract
A major reason for studying plant sex chromosomes is that they may often be 'young' systems. There is considerable evidence for the independent evolution of separate sexes within plant families or genera, in some cases showing that the maximum possible time during which their sex-determining genes have existed must be much shorter than those of several animal taxa. Consequently, their sex-linked regions could either have evolved soon after genetic sex determination arose or considerably later. Plants, therefore, include species with both young and old systems. I review several questions about the evolution of sex-determining systems and sex chromosomes that require studies of young systems, including: the kinds of mutations involved in the transition to unisexual reproduction from hermaphroditism or monoecy (a form of functional hermaphroditism); the times when they arose; and the extent to which the properties of sex-linked regions of genomes reflect responses to new selective situations created by the presence of a sex-determining locus. I also evaluate which questions are best studied in plants, vs other suitable candidate organisms. Studies of young plant systems can help understand general evolutionary processes that are shared with the sex chromosomes of other organisms.
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Affiliation(s)
- Deborah Charlesworth
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, West Mains Road, Edinburgh, EH9 3LF, UK
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14
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Li X, Veltsos P, Cossard GG, Gerchen J, Pannell JR. YY males of the dioecious plant Mercurialis annua are fully viable but produce largely infertile pollen. THE NEW PHYTOLOGIST 2019; 224:1394-1404. [PMID: 31230365 PMCID: PMC6852596 DOI: 10.1111/nph.16016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 06/10/2019] [Indexed: 05/07/2023]
Abstract
The suppression of recombination during sex-chromosome evolution is thought to be favoured by linkage between the sex-determining locus and sexually antagonistic loci, and leads to the degeneration of the chromosome restricted to the heterogametic sex. Despite substantial evidence for genetic degeneration at the sequence level, the phenotypic effects of the earliest stages of sex-chromosome evolution are poorly known. Here, we compare the morphology, viability and fertility between XY and YY individuals produced by crossing seed-producing males in the dioecious plant Mercurialis annua, which has young sex chromosomes with limited X-Y sequence divergence. We found no significant difference in viability or vegetative morphology between XY and YY males. However, electron microscopy revealed clear differences in pollen anatomy, and YY males were significantly poorer sires in competition with their XY counterparts. Our study suggests either that the X chromosome is required for full male fertility in M. annua, or that male fertility is sensitive to the dosage of relevant Y-linked genes. We discuss the possibility that the maintenance of male-fertility genes on the X chromosome might have been favoured in recent population expansions that selected for the ability of females to produce pollen in the absence of males.
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Affiliation(s)
- Xinji Li
- Department of Ecology and EvolutionUniversity of Lausanne1015LausanneSwitzerland
| | - Paris Veltsos
- Department of BiologyIndiana University1001 East Third StreetBloomingtonIN47405USA
| | - Guillaume G. Cossard
- Integrative Biology of Marine Organisms DepartmentStation Biologique CNRSPlace Georges TeissierRoscoff29688France
| | - Jörn Gerchen
- Department of Ecology and EvolutionUniversity of Lausanne1015LausanneSwitzerland
| | - John R. Pannell
- Department of Ecology and EvolutionUniversity of Lausanne1015LausanneSwitzerland
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15
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Veltsos P, Ridout KE, Toups MA, González-Martínez SC, Muyle A, Emery O, Rastas P, Hudzieczek V, Hobza R, Vyskot B, Marais GAB, Filatov DA, Pannell JR. Early Sex-Chromosome Evolution in the Diploid Dioecious Plant Mercurialis annua. Genetics 2019; 212:815-835. [PMID: 31113811 PMCID: PMC6614902 DOI: 10.1534/genetics.119.302045] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Accepted: 05/13/2019] [Indexed: 12/30/2022] Open
Abstract
Suppressed recombination allows divergence between homologous sex chromosomes and the functionality of their genes. Here, we reveal patterns of the earliest stages of sex-chromosome evolution in the diploid dioecious herb Mercurialis annua on the basis of cytological analysis, de novo genome assembly and annotation, genetic mapping, exome resequencing of natural populations, and transcriptome analysis. The genome assembly contained 34,105 expressed genes, of which 10,076 were assigned to linkage groups. Genetic mapping and exome resequencing of individuals across the species range both identified the largest linkage group, LG1, as the sex chromosome. Although the sex chromosomes of M. annua are karyotypically homomorphic, we estimate that about one-third of the Y chromosome, containing 568 transcripts and spanning 22.3 cM in the corresponding female map, has ceased recombining. Nevertheless, we found limited evidence for Y-chromosome degeneration in terms of gene loss and pseudogenization, and most X- and Y-linked genes appear to have diverged in the period subsequent to speciation between M. annua and its sister species M. huetii, which shares the same sex-determining region. Taken together, our results suggest that the M. annua Y chromosome has at least two evolutionary strata: a small old stratum shared with M. huetii, and a more recent larger stratum that is probably unique to M. annua and that stopped recombining ∼1 MYA. Patterns of gene expression within the nonrecombining region are consistent with the idea that sexually antagonistic selection may have played a role in favoring suppressed recombination.
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Affiliation(s)
- Paris Veltsos
- Department of Biology, Indiana University, Bloomington, IN 47405
- Department of Ecology and Evolution, University of Lausanne, CH-1015, Switzerland
| | - Kate E Ridout
- Department of Ecology and Evolution, University of Lausanne, CH-1015, Switzerland
- Department of Plant Sciences, University of Oxford, OX1 3RB, United Kingdom
- Department of Oncology, John Radcliffe Hospital, Oxford OX3 9DU, United Kingdom
| | - Melissa A Toups
- Department of Ecology and Evolution, University of Lausanne, CH-1015, Switzerland
- Department of Integrative Biology, University of Texas, Austin, 78712 Texas
| | | | - Aline Muyle
- Laboratoire Biométrie et Biologie Évolutive (UMR 5558), CNRS/Université Lyon 1, 69100 Villeurbanne, France
| | - Olivier Emery
- Department of Ecology and Evolution, University of Lausanne, CH-1015, Switzerland
| | - Pasi Rastas
- University of Helsinki, Institute of Biotechnology, 00014, Finland
| | - Vojtech Hudzieczek
- Department of Plant Developmental Genetics, Institute of Biophysics, Academy of Sciences of the Czech Republic, 61200 Brno, Czech Republic
| | - Roman Hobza
- Department of Plant Developmental Genetics, Institute of Biophysics, Academy of Sciences of the Czech Republic, 61200 Brno, Czech Republic
| | - Boris Vyskot
- Department of Plant Developmental Genetics, Institute of Biophysics, Academy of Sciences of the Czech Republic, 61200 Brno, Czech Republic
| | | | - Dmitry A Filatov
- Department of Plant Sciences, University of Oxford, OX1 3RB, United Kingdom
| | - John R Pannell
- Department of Ecology and Evolution, University of Lausanne, CH-1015, Switzerland
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16
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Santos Del Blanco L, Tudor E, Pannell JR. Low siring success of females with an acquired male function illustrates the legacy of sexual dimorphism in constraining the breakdown of dioecy. Ecol Lett 2019; 22:486-497. [PMID: 30618173 PMCID: PMC6850444 DOI: 10.1111/ele.13207] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Revised: 10/24/2018] [Accepted: 11/20/2018] [Indexed: 01/03/2023]
Abstract
Dioecy has often broken down in flowering plants, yielding functional hermaphroditism. We reasoned that evolutionary transitions from dioecy to functional hermaphroditism must overcome an inertia of sexual dimorphism, because modified males or females will express the opposite sexual function for which their phenotypes have been optimised. We tested this prediction by assessing the siring success of monoecious individuals of the plant Mercurialis annua with an acquired male function but that are phenotypically still female‐like. We found that pollen dispersed by female‐like monoecious individuals was ~ 1/3 poorer at siring outcrossed offspring than pollen from monoecious individuals with an alternative male‐like inflorescence. We conclude that whereas dioecy might evolve from functional hermaphroditism by conferring upon individuals certain benefits of sexual specialisation, reversion from a strategy of separate sexes to one of combined sexes must overcome constraints imposed by the advantages of sexual dimorphism. The breakdown of dioecy must therefore often be limited to situations in which outcrossing cannot be maintained and where selection favours a capacity for inbreeding by functional hermaphrodites.
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Affiliation(s)
- Luis Santos Del Blanco
- Department of Ecology and Evolution, Biophore Building, University of Lausanne, 1015, Lausanne, Switzerland
| | - Eleri Tudor
- Department of Plant Sciences, University of Oxford, Oxford, OX1 3RB, UK
| | - John R Pannell
- Department of Ecology and Evolution, Biophore Building, University of Lausanne, 1015, Lausanne, Switzerland
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17
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Hobza R, Hudzieczek V, Kubat Z, Cegan R, Vyskot B, Kejnovsky E, Janousek B. Sex and the flower - developmental aspects of sex chromosome evolution. ANNALS OF BOTANY 2018; 122:1085-1101. [PMID: 30032185 PMCID: PMC6324748 DOI: 10.1093/aob/mcy130] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Accepted: 07/13/2018] [Indexed: 05/07/2023]
Abstract
Background The evolution of dioecious plants is occasionally accompanied by the establishment of sex chromosomes: both XY and ZW systems have been found in plants. Structural studies of sex chromosomes are now being followed up by functional studies that are gradually shedding light on the specific genetic and epigenetic processes that shape the development of separate sexes in plants. Scope This review describes sex determination diversity in plants and the genetic background of dioecy, summarizes recent progress in the investigation of both classical and emerging model dioecious plants and discusses novel findings. The advantages of interspecies hybrids in studies focused on sex determination and the role of epigenetic processes in sexual development are also overviewed. Conclusions We integrate the genic, genomic and epigenetic levels of sex determination and stress the impact of sex chromosome evolution on structural and functional aspects of plant sexual development. We also discuss the impact of dioecy and sex chromosomes on genome structure and expression.
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Affiliation(s)
- Roman Hobza
- Department of Plant Developmental Genetics, Institute of Biophysics of the Czech Academy of Sciences, Kralovopolska, Brno, Czech Republic
| | - Vojtech Hudzieczek
- Department of Plant Developmental Genetics, Institute of Biophysics of the Czech Academy of Sciences, Kralovopolska, Brno, Czech Republic
| | - Zdenek Kubat
- Department of Plant Developmental Genetics, Institute of Biophysics of the Czech Academy of Sciences, Kralovopolska, Brno, Czech Republic
| | - Radim Cegan
- Department of Plant Developmental Genetics, Institute of Biophysics of the Czech Academy of Sciences, Kralovopolska, Brno, Czech Republic
| | - Boris Vyskot
- Department of Plant Developmental Genetics, Institute of Biophysics of the Czech Academy of Sciences, Kralovopolska, Brno, Czech Republic
| | - Eduard Kejnovsky
- Department of Plant Developmental Genetics, Institute of Biophysics of the Czech Academy of Sciences, Kralovopolska, Brno, Czech Republic
| | - Bohuslav Janousek
- Department of Plant Developmental Genetics, Institute of Biophysics of the Czech Academy of Sciences, Kralovopolska, Brno, Czech Republic
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