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da Roza PA, Muller H, Sullivan GJ, Walker RSK, Goold HD, Willows RD, Palenik B, Paulsen IT. Chromosome-scale assembly of the streamlined picoeukaryote Picochlorum sp. SENEW3 genome reveals Rabl-like chromatin structure and potential for C 4 photosynthesis. Microb Genom 2024; 10. [PMID: 38625719 DOI: 10.1099/mgen.0.001223] [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: 04/17/2024] Open
Abstract
Genome sequencing and assembly of the photosynthetic picoeukaryotic Picochlorum sp. SENEW3 revealed a compact genome with a reduced gene set, few repetitive sequences, and an organized Rabl-like chromatin structure. Hi-C chromosome conformation capture revealed evidence of possible chromosomal translocations, as well as putative centromere locations. Maintenance of a relatively few selenoproteins, as compared to similarly sized marine picoprasinophytes Mamiellales, and broad halotolerance compared to others in Trebouxiophyceae, suggests evolutionary adaptation to variable salinity environments. Such adaptation may have driven size and genome minimization and have been enabled by the retention of a high number of membrane transporters. Identification of required pathway genes for both CAM and C4 photosynthetic carbon fixation, known to exist in the marine mamiellale pico-prasinophytes and seaweed Ulva, but few other chlorophyte species, further highlights the unique adaptations of this robust alga. This high-quality assembly provides a significant advance in the resources available for genomic investigations of this and other photosynthetic picoeukaryotes.
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Affiliation(s)
- Patrick A da Roza
- ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney, NSW 2109, Australia
- School of Natural Sciences, Macquarie University, Sydney, Australia
| | - Héloïse Muller
- Institut Curie, PSL University, Sorbonne Université, CNRS, Nuclear Dynamics, 75005 Paris, France
| | - Geraldine J Sullivan
- ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney, NSW 2109, Australia
- School of Natural Sciences, Macquarie University, Sydney, Australia
| | - Roy S K Walker
- ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney, NSW 2109, Australia
- School of Natural Sciences, Macquarie University, Sydney, Australia
| | - Hugh D Goold
- ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney, NSW 2109, Australia
- New South Wales Department of Primary Industries, Orange, NSW 2800, Australia
| | - Robert D Willows
- School of Natural Sciences, Macquarie University, Sydney, Australia
| | - Brian Palenik
- Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California 92093-0202, USA
| | - Ian T Paulsen
- ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney, NSW 2109, Australia
- School of Natural Sciences, Macquarie University, Sydney, Australia
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Cang FA, Welles SR, Wong J, Ziaee M, Dlugosch KM. Genome size variation and evolution during invasive range expansion in an introduced plant. Evol Appl 2024; 17:e13624. [PMID: 38283607 PMCID: PMC10810172 DOI: 10.1111/eva.13624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 11/03/2023] [Accepted: 11/13/2023] [Indexed: 01/30/2024] Open
Abstract
Plants demonstrate exceptional variation in genome size across species, and their genome sizes can also vary dramatically across individuals and populations within species. This aspect of genetic variation can have consequences for traits and fitness, but few studies attributed genome size differentiation to ecological and evolutionary processes. Biological invasions present particularly useful natural laboratories to infer selective agents that might drive genome size shifts across environments and population histories. Here, we test hypotheses for the evolutionary causes of genome size variation across 14 invading populations of yellow starthistle, Centaurea solstitialis, in California, United States. We use a survey of genome sizes and trait variation to ask: (1) Is variation in genome size associated with developmental trait variation? (2) Are genome sizes smaller toward the leading edge of the expansion, consistent with selection for "colonizer" traits? Or alternatively, does genome size increase toward the leading edge of the expansion, consistent with predicted consequences of founder effects and drift? (3) Finally, are genome sizes smaller at higher elevations, consistent with selection for shorter development times? We found that 2C DNA content varied 1.21-fold among all samples, and was associated with flowering time variation, such that plants with larger genomes reproduced later, with lower lifetime capitula production. Genome sizes increased toward the leading edge of the invasion, but tended to decrease at higher elevations, consistent with genetic drift during range expansion but potentially strong selection for smaller genomes and faster development time at higher elevations. These results demonstrate how genome size variation can contribute to traits directly tied to reproductive success, and how selection and drift can shape that variation. We highlight the influence of genome size on dynamics underlying a rapid range expansion in a highly problematic invasive plant.
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Affiliation(s)
- F. Alice Cang
- Department of Ecology and Evolutionary BiologyUniversity of ArizonaTucsonArizonaUSA
| | - Shana R. Welles
- Department of Ecology and Evolutionary BiologyUniversity of ArizonaTucsonArizonaUSA
- Utah Valley UniversityOremUtahUSA
| | - Jenny Wong
- Department of Ecology and Evolutionary BiologyUniversity of ArizonaTucsonArizonaUSA
| | - Maia Ziaee
- Department of Ecology and Evolutionary BiologyUniversity of ArizonaTucsonArizonaUSA
- Mills CollegeOaklandCaliforniaUSA
| | - Katrina M. Dlugosch
- Department of Ecology and Evolutionary BiologyUniversity of ArizonaTucsonArizonaUSA
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Sun C, Xie YH, Li Z, Liu YJ, Sun XM, Li JJ, Quan WP, Zeng QY, Van de Peer Y, Zhang SG. The Larix kaempferi genome reveals new insights into wood properties. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2022; 64:1364-1373. [PMID: 35442564 DOI: 10.1111/jipb.13265] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 04/18/2022] [Indexed: 06/14/2023]
Abstract
Here, through single-molecule real-time sequencing, we present a high-quality genome sequence of the Japanese larch (Larix kaempferi), a conifer species with great value for wood production and ecological afforestation. The assembled genome is 10.97 Gb in size, harboring 45,828 protein-coding genes. Of the genome, 66.8% consists of repeat sequences, of which long terminal repeat retrotransposons are dominant and make up 69.86%. We find that tandem duplications have been responsible for the expansion of genes involved in transcriptional regulation and stress responses, unveiling their crucial roles in adaptive evolution. Population transcriptome analysis reveals that lignin content in L. kaempferi is mainly determined by the process of monolignol polymerization. The expression values of six genes (LkCOMT7, LkCOMT8, LkLAC23, LkLAC102, LkPRX148, and LkPRX166) have significantly positive correlations with lignin content. These results indicated that the increased expression of these six genes might be responsible for the high lignin content of the larches' wood. Overall, this study provides new genome resources for investigating the evolution and biological function of conifer trees, and also offers new insights into wood properties of larches.
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Affiliation(s)
- Chao Sun
- State Key Laboratory of Tree Genetics and Breeding, Chinese Academy of Forestry, Beijing, 100091, China
- Key Laboratory of Tree Breeding and Cultivation of the State Forestry and Grassland Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100091, China
| | - Yun-Hui Xie
- State Key Laboratory of Tree Genetics and Breeding, Chinese Academy of Forestry, Beijing, 100091, China
- Key Laboratory of Tree Breeding and Cultivation of the State Forestry and Grassland Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100091, China
| | - Zhen Li
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Gent, B-9052, Belgium
- VIB Center for Plant Systems Biology, Ghent, B-9052, Belgium
| | - Yan-Jing Liu
- State Key Laboratory of Tree Genetics and Breeding, Chinese Academy of Forestry, Beijing, 100091, China
| | - Xiao-Mei Sun
- State Key Laboratory of Tree Genetics and Breeding, Chinese Academy of Forestry, Beijing, 100091, China
- Key Laboratory of Tree Breeding and Cultivation of the State Forestry and Grassland Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100091, China
| | - Jing-Jing Li
- Nextomics Biosciences Co., Ltd, Wuhan, 430073, China
| | - Wei-Peng Quan
- Nextomics Biosciences Co., Ltd, Wuhan, 430073, China
| | - Qing-Yin Zeng
- State Key Laboratory of Tree Genetics and Breeding, Chinese Academy of Forestry, Beijing, 100091, China
| | - Yves Van de Peer
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Gent, B-9052, Belgium
- VIB Center for Plant Systems Biology, Ghent, B-9052, Belgium
- Department of Biochemistry, Genetics and Microbiology, Pretoria, South Africa
| | - Shou-Gong Zhang
- State Key Laboratory of Tree Genetics and Breeding, Chinese Academy of Forestry, Beijing, 100091, China
- Key Laboratory of Tree Breeding and Cultivation of the State Forestry and Grassland Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100091, China
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Evans DE, Mermet S, Tatout C. Advancing knowledge of the plant nuclear periphery and its application for crop science. Nucleus 2021; 11:347-363. [PMID: 33295233 PMCID: PMC7746251 DOI: 10.1080/19491034.2020.1838697] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
In this review, we explore recent advances in knowledge of the structure and dynamics of the plant nuclear envelope. As a paradigm, we focused our attention on the Linker of Nucleoskeleton and Cytoskeleton (LINC) complex, a structurally conserved bridging complex comprising SUN domain proteins in the inner nuclear membrane and KASH domain proteins in the outer nuclear membrane. Studies have revealed that this bridging complex has multiple functions with structural roles in positioning the nucleus within the cell, conveying signals across the membrane and organizing chromatin in the 3D nuclear space with impact on gene transcription. We also provide an up-to-date survey in nuclear dynamics research achieved so far in the model plant Arabidopsis thaliana that highlights its potential impact on several key plant functions such as growth, seed maturation and germination, reproduction and response to biotic and abiotic stress. Finally, we bring evidences that most of the constituents of the LINC Complex and associated components are, with some specificities, conserved in monocot and dicot crop species and are displaying very similar functions to those described for Arabidopsis. This leads us to suggest that a better knowledge of this system and a better account of its potential applications will in the future enhance the resilience and productivity of crop plants.
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Affiliation(s)
- David E Evans
- Department of Biological and Medical Sciences, Oxford Brookes University , Oxford, UK
| | - Sarah Mermet
- GReD, CNRS, INSERM, Université Clermont Auvergne , Clermont-Ferrand, France
| | - Christophe Tatout
- GReD, CNRS, INSERM, Université Clermont Auvergne , Clermont-Ferrand, France
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Du YP, Bi Y, Zhang MF, Yang FP, Jia GX, Zhang XH. Genome Size Diversity in Lilium (Liliaceae) Is Correlated with Karyotype and Environmental Traits. FRONTIERS IN PLANT SCIENCE 2017; 8:1303. [PMID: 28798759 PMCID: PMC5526928 DOI: 10.3389/fpls.2017.01303] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Accepted: 07/11/2017] [Indexed: 05/25/2023]
Abstract
Genome size (GS) diversity is of fundamental biological importance. The occurrence of giant genomes in angiosperms is restricted to just a few lineages in the analyzed genome size of plant species so far. It is still an open question whether GS diversity is shaped by neutral or natural selection. The genus Lilium, with giant genomes, is phylogenetically and horticulturally important and is distributed throughout the northern hemisphere. GS diversity in Lilium and the underlying evolutionary mechanisms are poorly understood. We performed a comprehensive study involving phylogenetically independent analysis on 71 species to explore the diversity and evolution of GS and its correlation with karyological and environmental traits within Lilium (including Nomocharis). The strong phylogenetic signal detected for GS in the genus provides evidence consistent with that the repetitive DNA may be the primary contributors to the GS diversity, while the significant positive relationships detected between GS and the haploid chromosome length (HCL) provide insights into patterns of genome evolution. The relationships between GS and karyotypes indicate that ancestral karyotypes of Lilium are likely to have exhibited small genomes, low diversity in centromeric index (CVCI) values and relatively high relative variation in chromosome length (CVCL) values. Significant relationships identified between GS and annual temperature and between GS and annual precipitation suggest that adaptation to habitat strongly influences GS diversity. We conclude that GS in Lilium is shaped by both neutral (genetic drift) and adaptive evolution. These findings will have important consequences for understanding the evolution of giant plant genomes, and exploring the role of repetitive DNA fraction and chromosome changes in a plant group with large genomes and conservation of chromosome number.
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Affiliation(s)
- Yun-peng Du
- Beijing Agro-Biotechnology Research Center, Beijing Academy of Agriculture and Forestry SciencesBeijing, China
- Beijing Key Laboratory of Agricultural Genetic Resources and Biotechnology, Beijing Engineering Technology Research Center of Functional FloricultureBeijing, China
- Beijing Key Laboratory of Ornamental Plants Germplasm Innovation & Molecular Breeding, National Engineering Research Center for Floriculture and College of Landscape Architecture, Beijing Forestry UniversityBeijing, China
| | - Yu Bi
- Beijing Agro-Biotechnology Research Center, Beijing Academy of Agriculture and Forestry SciencesBeijing, China
- Beijing Key Laboratory of Agricultural Genetic Resources and Biotechnology, Beijing Engineering Technology Research Center of Functional FloricultureBeijing, China
| | - Ming-fang Zhang
- Beijing Agro-Biotechnology Research Center, Beijing Academy of Agriculture and Forestry SciencesBeijing, China
- Beijing Key Laboratory of Agricultural Genetic Resources and Biotechnology, Beijing Engineering Technology Research Center of Functional FloricultureBeijing, China
| | - Feng-ping Yang
- Beijing Agro-Biotechnology Research Center, Beijing Academy of Agriculture and Forestry SciencesBeijing, China
- Beijing Key Laboratory of Agricultural Genetic Resources and Biotechnology, Beijing Engineering Technology Research Center of Functional FloricultureBeijing, China
| | - Gui-xia Jia
- Beijing Key Laboratory of Ornamental Plants Germplasm Innovation & Molecular Breeding, National Engineering Research Center for Floriculture and College of Landscape Architecture, Beijing Forestry UniversityBeijing, China
| | - Xiu-hai Zhang
- Beijing Agro-Biotechnology Research Center, Beijing Academy of Agriculture and Forestry SciencesBeijing, China
- Beijing Key Laboratory of Agricultural Genetic Resources and Biotechnology, Beijing Engineering Technology Research Center of Functional FloricultureBeijing, China
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Poulet A, Probst AV, Graumann K, Tatout C, Evans D. Exploring the evolution of the proteins of the plant nuclear envelope. Nucleus 2017; 8:46-59. [PMID: 27644504 PMCID: PMC5287204 DOI: 10.1080/19491034.2016.1236166] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Revised: 08/22/2016] [Accepted: 09/07/2016] [Indexed: 10/21/2022] Open
Abstract
In this study, we explore the plasticity during evolution of proteins of the higher plant nuclear envelope (NE) from the most ancestral plant species to advanced angiosperms. The higher plant NE contains a functional Linker of Nucleoskeleton and Cytoskeleton (LINC) complex based on conserved Sad1-Unc84 (SUN) domain proteins and plant specific Klarsicht/Anc1/Syne homology (KASH) domain proteins. Recent evidence suggests the presence of a plant lamina underneath the inner membrane and various coiled-coil proteins have been hypothesized to be associated with it including Crowded Nuclei (CRWN; also termed LINC and NMCP), Nuclear Envelope Associated Protein (NEAP) protein families as well as the CRWN binding protein KAKU4. SUN domain proteins appear throughout with a key role for mid-SUN proteins suggested. Evolution of KASH domain proteins has resulted in increasing complexity, with some appearing in all species considered, while other KASH proteins are progressively gained during evolution. Failure to identify CRWN homologs in unicellular organisms included in the study and their presence in plants leads us to speculate that convergent evolution may have occurred in the formation of the lamina with each kingdom having new proteins such as the Lamin B receptor (LBR) and Lamin-Emerin-Man1 (LEM) domain proteins (animals) or NEAPs and KAKU4 (plants). Our data support a model in which increasing complexity at the nuclear envelope occurred through the plant lineage and suggest a key role for mid-SUN proteins as an early and essential component of the nuclear envelope.
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Affiliation(s)
- Axel Poulet
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, UK
- UMR CNRS 6293 INSERM U1103 Clermont Université, GReD, Aubière, France
| | - Aline V. Probst
- UMR CNRS 6293 INSERM U1103 Clermont Université, GReD, Aubière, France
| | - Katja Graumann
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, UK
| | - Christophe Tatout
- UMR CNRS 6293 INSERM U1103 Clermont Université, GReD, Aubière, France
| | - David Evans
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, UK
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7
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Coates BS, Abel CA, Perera OP. Estimation of long terminal repeat element content in the Helicoverpa zea genome from high-throughput sequencing of bacterial artificial chromosome pools. Genome 2016; 60:310-324. [PMID: 28177843 DOI: 10.1139/gen-2016-0067] [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] [Indexed: 12/23/2022]
Abstract
The lepidopteran pest insect Helicoverpa zea feeds on cultivated corn and cotton across the Americas where control remains challenging owing to the evolution of resistance to chemical and transgenic insecticidal toxins, yet genomic resources remain scarce for this species. A bacterial artificial chromosome (BAC) library having a mean genomic insert size of 145 ± 20 kbp was created from a laboratory strain of H. zea, which provides ∼12.9-fold coverage of a 362.8 ± 8.8 Mbp (0.37 ± 0.09 pg) flow cytometry estimated haploid genome size. Assembly of Illumina HiSeq 2000 reads generated from 14 pools that encompassed all BAC clones resulted in 165 485 genomic contigs (N50 = 3262 bp; 324.6 Mbp total). Long terminal repeat (LTR) protein coding regions annotated from 181 contigs included 30 Ty1/copia, 78 Ty3/gypsy, and 73 BEL/Pao elements, of which 60 (33.1%) encoded all five functional polyprotein (pol) domains. Approximately 14% of LTR elements are distributed non-randomly across pools of BAC clones.
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Affiliation(s)
- Brad S Coates
- a USDA-ARS, Corn Insects & Crop Genetics Research Unit, Genetics Laboratory, Iowa State University, Ames, IA 50011, USA.,b Department of Entomology, Iowa State University, Ames, IA 50011, USA
| | - Craig A Abel
- a USDA-ARS, Corn Insects & Crop Genetics Research Unit, Genetics Laboratory, Iowa State University, Ames, IA 50011, USA
| | - Omaththage P Perera
- c USDA-ARS, Southern Insect Management Research Unit, 141 Experiment Station Road, P.O. Box 346, Stoneville, MS 38776, USA
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8
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Lwin AK, Bertolini E, Pè ME, Zuccolo A. Genomic skimming for identification of medium/highly abundant transposable elements in Arundo donax and Arundo plinii. Mol Genet Genomics 2016; 292:157-171. [PMID: 27778102 DOI: 10.1007/s00438-016-1263-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 10/17/2016] [Indexed: 11/29/2022]
Abstract
Transposable elements (TEs) are the most abundant genetic material for almost all eukaryotic genomes. Their effects on the host genomes range from an extensive size variation to the regulation of gene expression, altering gene function and creating new genes. Because of TEs pivotal contribute to the host genome structure and regulation, their identification and characterization provide a wealth of useful data for gaining an in-depth understanding of host genome functioning. The giant reed (Arundo donax) is a perennial rhizomatous C3 grass, octadecaploid, with an estimated nuclear genome size of 2744 Mbp. It is a promising feedstock for second-generation biofuels and biomethane production. To identify and characterize the most repetitive TEs in the genomes of A. donax and its ancestral A. plinii species, we carried out low-coverage whole genome shotgun sequencing for both species. Using a de novo repeat identification approach, 33,041 and 28,237 non-redundant repetitive sequences were identified and characterized in A. donax and A. plinii genomes, representing 37.55 and 31.68% of each genome, respectively. Comparative phylogenetic analyses, including the major TE classes identified in A. donax and A. plinii, together with rice and maize TE paralogs, were carried out to understand the evolutionary relationship of the most abundant TE classes. Highly conserved copies of RIRE1-like Ty1-Copia elements were discovered in two Arundo spp. in which they represented nearly 3% of each genomic sequence. We identified and characterized the medium/highly repetitive TEs in two unexplored polyploid genomes, thus generating useful information for the study of the genomic structure, composition, and functioning of these two non-model species. We provided a valuable resource that could be exploited in any effort aimed at sequencing and assembling these two genomes.
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Affiliation(s)
- Aung Kyaw Lwin
- Institute of Life Sciences, Scuola Superiore Sant'Anna, Piazza Martiri della Libertà, 33, 56127, Pisa, Italy.,Sugarcane Research and Seed Farm, Pyinmana, Nay Pyi Taw, Myanmar
| | - Edoardo Bertolini
- Institute of Life Sciences, Scuola Superiore Sant'Anna, Piazza Martiri della Libertà, 33, 56127, Pisa, Italy
| | - Mario Enrico Pè
- Institute of Life Sciences, Scuola Superiore Sant'Anna, Piazza Martiri della Libertà, 33, 56127, Pisa, Italy
| | - Andrea Zuccolo
- Institute of Life Sciences, Scuola Superiore Sant'Anna, Piazza Martiri della Libertà, 33, 56127, Pisa, Italy.
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Zenil-Ferguson R, Ponciano JM, Burleigh JG. Evaluating the role of genome downsizing and size thresholds from genome size distributions in angiosperms. AMERICAN JOURNAL OF BOTANY 2016; 103:1175-1186. [PMID: 27206462 DOI: 10.3732/ajb.1500408] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2016] [Accepted: 01/07/2016] [Indexed: 06/05/2023]
Abstract
PREMISE OF THE STUDY Whole-genome duplications (WGDs) can rapidly increase genome size in angiosperms. Yet their mean genome size is not correlated with ploidy. We compared three hypotheses to explain the constancy of genome size means across ploidies. The genome downsizing hypothesis suggests that genome size will decrease by a given percentage after a WGD. The genome size threshold hypothesis assumes that taxa with large genomes or large monoploid numbers will fail to undergo or survive WGDs. Finally, the genome downsizing and threshold hypothesis suggests that both genome downsizing and thresholds affect the relationship between genome size means and ploidy. METHODS We performed nonparametric bootstrap simulations to compare observed angiosperm genome size means among species or genera against simulated genome sizes under the three different hypotheses. We evaluated the hypotheses using a decision theory approach and estimated the expected percentage of genome downsizing. KEY RESULTS The threshold hypothesis improves the approximations between mean genome size and simulated genome size. At the species level, the genome downsizing with thresholds hypothesis best explains the genome size means with a 15% genome downsizing percentage. In the genus level simulations, the monoploid number threshold hypothesis best explains the data. CONCLUSIONS Thresholds of genome size and monoploid number added to genome downsizing at species level simulations explain the observed means of angiosperm genome sizes, and monoploid number is important for determining the genome size mean at the genus level.
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Affiliation(s)
- Rosana Zenil-Ferguson
- Department of Biology, University of Florida, P. O. Box 118525, Gainesville, Florida 32611-8525 USA
| | - José M Ponciano
- Department of Biology, University of Florida, P. O. Box 118525, Gainesville, Florida 32611-8525 USA
| | - J Gordon Burleigh
- Department of Biology, University of Florida, P. O. Box 118525, Gainesville, Florida 32611-8525 USA
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Aguirre-Liguori JA, Aguirre-Planter E, Eguiarte LE. Genetics and Ecology of Wild and Cultivated Maize: Domestication and Introgression. ETHNOBOTANY OF MEXICO 2016. [DOI: 10.1007/978-1-4614-6669-7_16] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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11
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Mukherjee D, Mukherjee A, Ghosh TC. Evolutionary Rate Heterogeneity of Primary and Secondary Metabolic Pathway Genes in Arabidopsis thaliana. Genome Biol Evol 2015; 8:17-28. [PMID: 26556590 PMCID: PMC4758233 DOI: 10.1093/gbe/evv217] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Primary metabolism is essential to plants for growth and development, and secondary metabolism helps plants to interact with the environment. Many plant metabolites are industrially important. These metabolites are produced by plants through complex metabolic pathways. Lack of knowledge about these pathways is hindering the successful breeding practices for these metabolites. For a better knowledge of the metabolism in plants as a whole, evolutionary rate variation of primary and secondary metabolic pathway genes is a prerequisite. In this study, evolutionary rate variation of primary and secondary metabolic pathway genes has been analyzed in the model plant Arabidopsis thaliana. Primary metabolic pathway genes were found to be more conserved than secondary metabolic pathway genes. Several factors such as gene structure, expression level, tissue specificity, multifunctionality, and domain number are the key factors behind this evolutionary rate variation. This study will help to better understand the evolutionary dynamics of plant metabolism.
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Affiliation(s)
- Dola Mukherjee
- Bioinformatics Centre, Bose Institute, Kolkata, West Bengal, India
| | - Ashutosh Mukherjee
- Department of Botany, Vivekananda College, Thakurpukur, Kolkata, West Bengal, India
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12
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Bardil A, Tayalé A, Parisod C. Evolutionary dynamics of retrotransposons following autopolyploidy in the Buckler Mustard species complex. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2015; 82:621-31. [PMID: 25823965 DOI: 10.1111/tpj.12837] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Revised: 03/18/2015] [Accepted: 03/23/2015] [Indexed: 05/21/2023]
Abstract
Long terminal repeat retrotransposons (LTR-RTs) represent a major fraction of plant genomes, but processes leading to transposition bursts remain elusive. Polyploidy expectedly leads to LTR-RT proliferation, as the merging of divergent diploids provokes a genome shock activating LTR-RTs and/or genetic redundancy supports the accumulation of active LTR-RTs through relaxation of selective constraints. Available evidence supports interspecific hybridization as the main trigger of genome dynamics, but few studies have addressed the consequences of intraspecific polyploidy (i.e. autopolyploidy), where the genome shock is expectedly minimized. The dynamics of LTR-RTs was thus here evaluated through low coverage 454 sequencing of three closely related diploid progenitors and three independent autotetraploids from the young Biscutella laevigata species complex. Genomes from this early diverging Brassicaceae lineage presented a minimum of 40% repeats and a large diversity of transposable elements. Differential abundances and patterns of sequence divergence among genomes for 37 LTR-RT families revealed contrasted dynamics during species diversification. Quiescent LTR-RT families with limited genetic variation among genomes were distinguished from active families (37.8%) having proliferated in specific taxa. Specific families proliferated in autopolyploids only, but most transpositionally active families in polyploids were also differentiated among diploids. Low expression levels of transpositionally active LTR-RT families in autopolyploids further supported that genome shock and redundancy are non-mutually exclusive triggers of LTR-RT proliferation. Although reputed stable, autopolyploid genomes show LTR-RT fractions presenting analogies with polyploids between widely divergent genomes.
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Affiliation(s)
- Amélie Bardil
- Laboratory of Evolutionary Botany, University of Neuchâtel, Neuchâtel, 2000, Switzerland
| | - Alexandre Tayalé
- Laboratory of Evolutionary Botany, University of Neuchâtel, Neuchâtel, 2000, Switzerland
| | - Christian Parisod
- Laboratory of Evolutionary Botany, University of Neuchâtel, Neuchâtel, 2000, Switzerland
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13
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Ågren JA, Greiner S, Johnson MTJ, Wright SI. No evidence that sex and transposable elements drive genome size variation in evening primroses. Evolution 2015; 69:1053-62. [PMID: 25690700 DOI: 10.1111/evo.12627] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Accepted: 01/13/2015] [Indexed: 01/05/2023]
Abstract
Genome size varies dramatically across species, but despite an abundance of attention there is little agreement on the relative contributions of selective and neutral processes in governing this variation. The rate of sex can potentially play an important role in genome size evolution because of its effect on the efficacy of selection and transmission of transposable elements (TEs). Here, we used a phylogenetic comparative approach and whole genome sequencing to investigate the contribution of sex and TE content to genome size variation in the evening primrose (Oenothera) genus. We determined genome size using flow cytometry for 30 species that vary in genetic system and find that variation in sexual/asexual reproduction cannot explain the almost twofold variation in genome size. Moreover, using whole genome sequences of three species of varying genome sizes and reproductive system, we found that genome size was not associated with TE abundance; instead the larger genomes had a higher abundance of simple sequence repeats. Although it has long been clear that sexual reproduction may affect various aspects of genome evolution in general and TE evolution in particular, it does not appear to have played a major role in genome size evolution in the evening primroses.
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Affiliation(s)
- J Arvid Ågren
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, M5S 3B2, Canada.
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Genetics of cryptic speciation within an Arctic mustard, Draba nivalis. PLoS One 2014; 9:e93834. [PMID: 24691072 PMCID: PMC3972243 DOI: 10.1371/journal.pone.0093834] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Accepted: 03/09/2014] [Indexed: 01/13/2023] Open
Abstract
Crossing experiments indicate that hybrid sterility barriers frequently have developed within diploid, circumpolar plant species of the genus Draba. To gain insight into the rapid evolution of postzygotic reproductive isolation in this system, we augmented the linkage map of one of these species, D. nivalis, and searched for quantitative trait loci (QTLs) associated with reproductive isolation. The map adds 63 new dominant markers to a previously published dataset of 31 co-dominant microsatellites. These markers include 52 amplified fragment length polymorphisms (AFLPs) and 11 sequence-specific amplified polymorphisms (SSAPs) based on retrotransposon sequence. 22 markers displaying transmission ratio distortion were further included in the map. We resolved eight linkage groups with a total map length of 894 cM. Significant genotype-trait associations, or quantitative trait loci (QTL), were detected for reproductive phenotypes including pollen fertility (4 QTLs), seed set (3 QTLs), flowering time (3 QTLs) and number of flowers (4 QTLs). Observed patterns of inheritance were consistent with the influence of both nuclear-nuclear interactions and chromosomal changes on these traits. All seed set QTLs and one pollen fertility QTL displayed underdominant effects suggestive of the involvement of chromosomal rearrangements in hybrid sterility. Interestingly, D. nivalis is predominantly self-fertilizing, which may facilitate the establishment of underdominant loci and contribute to reproductive isolation.
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15
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Michael TP. Plant genome size variation: bloating and purging DNA. Brief Funct Genomics 2014; 13:308-17. [DOI: 10.1093/bfgp/elu005] [Citation(s) in RCA: 102] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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16
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Parisod C, Salmon A, Ainouche M, Grandbastien MA. Detecting epigenetic effects of transposable elements in plants. Methods Mol Biol 2014; 1112:211-217. [PMID: 24478017 DOI: 10.1007/978-1-62703-773-0_14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Transposable elements (TE) represent a major fraction of eukaryotic genomes and play many roles in plant epigenetics. In this chapter, we describe the use of Sequence-Specific Amplified Polymorphism (SSAP) as a reliable Transposon Display technique applicable for use in many plant species. We also discuss the interpretation of SSAP data and associated risks. This technique has potential to allow rapid screening of plant populations, especially in nonmodel or wild species.
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Affiliation(s)
- Christian Parisod
- Laboratory of Evolutionary Botany, Biology Institute, University of Neuchâtel, Neuchâtel, Switzerland
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17
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Schulman AH. Retrotransposon replication in plants. Curr Opin Virol 2013; 3:604-14. [PMID: 24035277 DOI: 10.1016/j.coviro.2013.08.009] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Revised: 08/16/2013] [Accepted: 08/19/2013] [Indexed: 12/31/2022]
Abstract
Retrotransposons comprise the bulk of large plant genomes, replicating via an RNA intermediate whereby the original, integrated element remains in place. Of the two main orders, the LTR retrotransposons considerably outnumber the LINEs. LINEs integrate into target sites simultaneously with the RNA transcript being copied into cDNA by target-primed reverse transcription. LTR retrotransposon replication is basically equivalent to the intracellular phase of retroviral life cycles. The envelope gene giving extracellular mobility to retroviruses is in fact widespread in plants and their retrotransposons. Evolutionary analyses of the retrotransposons and retroviruses suggest that both form an ancient monophyletic group. The particular adaptations of LTR retrotransposons to plant life cycles enabling their success remain to be clarified.
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Affiliation(s)
- Alan H Schulman
- Institute of Biotechnology, Viikki Biocenter, University of Helsinki, P.O. Box 65, Helsinki FIN-00014, Finland; Biotechnology and Food Research, MTT Agrifood Research Finland, Jokioinen FIN-31600, Finland.
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18
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Genómica de Poblaciones: Nada en Evolución va a tener sentido si no es a la luz de la Genómica, y nada en Genómica tendrá sentido si no es a la luz de la Evolución. TIP REVISTA ESPECIALIZADA EN CIENCIAS QUÍMICO-BIOLÓGICAS 2013. [DOI: 10.1016/s1405-888x(13)72077-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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19
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Senerchia N, Wicker T, Felber F, Parisod C. Evolutionary dynamics of retrotransposons assessed by high-throughput sequencing in wild relatives of wheat. Genome Biol Evol 2013; 5:1010-20. [PMID: 23595021 PMCID: PMC4104650 DOI: 10.1093/gbe/evt064] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/11/2013] [Indexed: 12/23/2022] Open
Abstract
Transposable elements (TEs) represent a major fraction of plant genomes and drive their evolution. An improved understanding of genome evolution requires the dynamics of a large number of TE families to be considered. We put forward an approach bypassing the required step of a complete reference genome to assess the evolutionary trajectories of high copy number TE families from genome snapshot with high-throughput sequencing. Low coverage sequencing of the complex genomes of Aegilops cylindrica and Ae. geniculata using 454 identified more than 70% of the sequences as known TEs, mainly long terminal repeat (LTR) retrotransposons. Comparing the abundance of reads as well as patterns of sequence diversity and divergence within and among genomes assessed the dynamics of 44 major LTR retrotransposon families of the 165 identified. In particular, molecular population genetics on individual TE copies distinguished recently active from quiescent families and highlighted different evolutionary trajectories of retrotransposons among related species. This work presents a suite of tools suitable for current sequencing data, allowing to address the genome-wide evolutionary dynamics of TEs at the family level and advancing our understanding of the evolution of nonmodel genomes.
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Affiliation(s)
- Natacha Senerchia
- Laboratory of Evolutionary Botany, Institute of Biology, University of Neuchâtel, Switzerland
| | - Thomas Wicker
- Institute of Plant Biology, University of Zurich, Switzerland
| | - François Felber
- Laboratory of Evolutionary Botany, Institute of Biology, University of Neuchâtel, Switzerland
- Musée et Jardins botaniques cantonaux, Lausanne, Switzerland
| | - Christian Parisod
- Laboratory of Evolutionary Botany, Institute of Biology, University of Neuchâtel, Switzerland
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20
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Mackay J, Dean JFD, Plomion C, Peterson DG, Cánovas FM, Pavy N, Ingvarsson PK, Savolainen O, Guevara MÁ, Fluch S, Vinceti B, Abarca D, Díaz-Sala C, Cervera MT. Towards decoding the conifer giga-genome. PLANT MOLECULAR BIOLOGY 2012; 80:555-69. [PMID: 22960864 DOI: 10.1007/s11103-012-9961-7] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2012] [Accepted: 08/24/2012] [Indexed: 05/21/2023]
Abstract
Several new initiatives have been launched recently to sequence conifer genomes including pines, spruces and Douglas-fir. Owing to the very large genome sizes ranging from 18 to 35 gigabases, sequencing even a single conifer genome had been considered unattainable until the recent throughput increases and cost reductions afforded by next generation sequencers. The purpose of this review is to describe the context for these new initiatives. A knowledge foundation has been acquired in several conifers of commercial and ecological interest through large-scale cDNA analyses, construction of genetic maps and gene mapping studies aiming to link phenotype and genotype. Exploratory sequencing in pines and spruces have pointed out some of the unique properties of these giga-genomes and suggested strategies that may be needed to extract value from their sequencing. The hope is that recent and pending developments in sequencing technology will contribute to rapidly filling the knowledge vacuum surrounding their structure, contents and evolution. Researchers are also making plans to use comparative analyses that will help to turn the data into a valuable resource for enhancing and protecting the world's conifer forests.
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Affiliation(s)
- John Mackay
- Center for Forest Research, Institute for Integrative and Systems Biology, Université Laval, Québec, Québec G1V 0A6, Canada
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21
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Parisod C, Mhiri C, Lim KY, Clarkson JJ, Chase MW, Leitch AR, Grandbastien MA. Differential dynamics of transposable elements during long-term diploidization of Nicotiana section Repandae (Solanaceae) allopolyploid genomes. PLoS One 2012; 7:e50352. [PMID: 23185607 PMCID: PMC3503968 DOI: 10.1371/journal.pone.0050352] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Accepted: 10/18/2012] [Indexed: 01/26/2023] Open
Abstract
Evidence accumulated over the last decade has shown that allopolyploid genomes may undergo drastic reorganization. However, timing and mechanisms of structural diploidization over evolutionary timescales are still poorly known. As transposable elements (TEs) represent major and labile components of plant genomes, they likely play a pivotal role in fuelling genome changes leading to long-term diploidization. Here, we exploit the 4.5 MY old allopolyploid Nicotiana section Repandae to investigate the impact of TEs on the evolutionary dynamics of genomes. Sequence-specific amplified polymorphisms (SSAP) on seven TEs with expected contrasted dynamics were used to survey genome-wide TE insertion polymorphisms. Comparisons of TE insertions in the four allopolyploid species and descendents of the diploid species most closely related to their actual progenitors revealed that the polyploids showed considerable departure from predicted additivity of the diploids. Large numbers of new SSAP bands were observed in polyploids for two TEs, but restructuring for most TE families involved substantial loss of fragments relative to the genome of the diploid representing the paternal progenitor, which could be due to changes in allopolyploids, diploid progenitor lineages or both. The majority of non-additive bands were shared by all polyploid species, suggesting that significant restructuring occurred early after the allopolyploid event that gave rise to their common ancestor. Furthermore, several gains and losses of SSAP fragments were restricted to N. repanda, suggesting a unique evolutionary trajectory. This pattern of diploidization in TE genome fractions supports the hypothesis that TEs are central to long-term genome turnover and depends on both TE and the polyploid lineage considered.
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Affiliation(s)
- Christian Parisod
- Institut Jean-Pierre Bourgin, UMR 1318 INRA-AgroParisTech, INRA-Versailles, Versailles, France
| | - Corinne Mhiri
- Institut Jean-Pierre Bourgin, UMR 1318 INRA-AgroParisTech, INRA-Versailles, Versailles, France
| | - K. Yoong Lim
- School of Biological Sciences, Queen Mary University of London, London, United Kingdom
| | - James J. Clarkson
- Jodrell Laboratory, Royal Botanic Gardens, Kew, Richmond, Surrey, United Kingdom
| | - Mark W. Chase
- Jodrell Laboratory, Royal Botanic Gardens, Kew, Richmond, Surrey, United Kingdom
| | - Andrew R. Leitch
- School of Biological Sciences, Queen Mary University of London, London, United Kingdom
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22
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Muñoz-Diez C, Vitte C, Ross-Ibarra J, Gaut BS, Tenaillon MI. Using Nextgen Sequencing to Investigate Genome Size Variation and Transposable Element Content. PLANT TRANSPOSABLE ELEMENTS 2012. [DOI: 10.1007/978-3-642-31842-9_3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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23
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Parisod C, Senerchia N. Responses of Transposable Elements to Polyploidy. PLANT TRANSPOSABLE ELEMENTS 2012. [DOI: 10.1007/978-3-642-31842-9_9] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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25
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Hu TT, Pattyn P, Bakker EG, Cao J, Cheng JF, Clark RM, Fahlgren N, Fawcett JA, Grimwood J, Gundlach H, Haberer G, Hollister JD, Ossowski S, Ottilar RP, Salamov AA, Schneeberger K, Spannagl M, Wang X, Yang L, Nasrallah ME, Bergelson J, Carrington JC, Gaut BS, Schmutz J, Mayer KFX, Van de Peer Y, Grigoriev IV, Nordborg M, Weigel D, Guo YL. The Arabidopsis lyrata genome sequence and the basis of rapid genome size change. Nat Genet 2011; 43:476-81. [PMID: 21478890 PMCID: PMC3083492 DOI: 10.1038/ng.807] [Citation(s) in RCA: 596] [Impact Index Per Article: 45.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2010] [Accepted: 03/18/2011] [Indexed: 12/19/2022]
Abstract
We report the 207-Mb genome sequence of the North American Arabidopsis lyrata strain MN47 based on 8.3× dideoxy sequence coverage. We predict 32,670 genes in this outcrossing species compared to the 27,025 genes in the selfing species Arabidopsis thaliana. The much smaller 125-Mb genome of A. thaliana, which diverged from A. lyrata 10 million years ago, likely constitutes the derived state for the family. We found evidence for DNA loss from large-scale rearrangements, but most of the difference in genome size can be attributed to hundreds of thousands of small deletions, mostly in noncoding DNA and transposons. Analysis of deletions and insertions still segregating in A. thaliana indicates that the process of DNA loss is ongoing, suggesting pervasive selection for a smaller genome. The high-quality reference genome sequence for A. lyrata will be an important resource for functional, evolutionary and ecological studies in the genus Arabidopsis.
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Affiliation(s)
- Tina T Hu
- Molecular and Computational Biology, University of Southern California, Los Angeles, California, USA
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26
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Yotoko KSC, Dornelas MC, Togni PD, Fonseca TC, Salzano FM, Bonatto SL, Freitas LB. Does variation in genome sizes reflect adaptive or neutral processes? New clues from Passiflora. PLoS One 2011; 6:e18212. [PMID: 21464897 PMCID: PMC3065483 DOI: 10.1371/journal.pone.0018212] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2010] [Accepted: 02/23/2011] [Indexed: 02/02/2023] Open
Abstract
One of the long-standing paradoxes in genomic evolution is the observation that much of the genome is composed of repetitive DNA which has been typically regarded as superfluous to the function of the genome in generating phenotypes. In this work, we used comparative phylogenetic approaches to investigate if the variations in genome sizes (GS) should be considered as adaptive or neutral processes by the comparison between GS and flower diameters (FD) of 50 Passiflora species, more specifically, within its two most species-rich subgenera, Passiflora and Decaloba. For this, we have constructed a phylogenetic tree of these species, estimated GS and FD of them, inferred the tempo and mode of evolution of these traits and their correlations, using both current and phylogenetically independent contrasted values. We found significant correlations among the traits, when considering the complete set of data or only the subgenus Passiflora, whereas no correlations were observed within Decaloba. Herein, we present convincing evidence of adaptive evolution of GS, as well as clues that this pattern is limited by a minimum genome size, which could reduce both the possibilities of changes in GS and the possibility of phenotypic responses to environment changes.
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Affiliation(s)
- Karla S. C. Yotoko
- Laboratório de Bioinformática e Evolução, Departamento de Biologia Geral, Universidade Federal de Viçosa, Viçosa, Brazil
| | - Marcelo C. Dornelas
- Departamento de Biologia Vegetal, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, Brazil
| | - Pakisa D. Togni
- Laboratório de Evolução Molecular, Departamento de Genética, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Tamara C. Fonseca
- Departamento de Biologia Vegetal, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, Brazil
| | - Francisco M. Salzano
- Laboratório de Evolução Molecular, Departamento de Genética, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Sandro L. Bonatto
- Laboratório de Biologia Genômica e Molecular, Faculdade de Biociências, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil
| | - Loreta B. Freitas
- Laboratório de Evolução Molecular, Departamento de Genética, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
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27
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Yang L, Gaut BS. Factors that contribute to variation in evolutionary rate among Arabidopsis genes. Mol Biol Evol 2011; 28:2359-69. [PMID: 21389272 DOI: 10.1093/molbev/msr058] [Citation(s) in RCA: 136] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Surprisingly, few studies have described evolutionary rate variation among plant nuclear genes, with little investigation of the causes of rate variation. Here, we describe evolutionary rates for 11,492 ortholog pairs between Arabidopsis thaliana and A. lyrata and investigate possible contributors to rate variation among these genes. Rates of evolution at synonymous sites vary along chromosomes, suggesting that mutation rates vary on genomic scales, perhaps as a function of recombination rate. Rates of evolution at nonsynonymous sites correlate most strongly with expression patterns, but they also vary as to whether a gene is duplicated and retained after a whole-genome duplication (WGD) event. WGD genes evolve more slowly, on average, than nonduplicated genes and non-WGD duplicates. We hypothesize that levels and patterns of expression are not only the major determinants that explain nonsynonymous rate variation among genes but also a critical determinant of gene retention after duplication.
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Affiliation(s)
- Liang Yang
- Department of Ecology and Evolutionary Biology, University of California Irvine, Irvine, USA
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28
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Tenaillon MI, Hufford MB, Gaut BS, Ross-Ibarra J. Genome size and transposable element content as determined by high-throughput sequencing in maize and Zea luxurians. Genome Biol Evol 2011; 3:219-29. [PMID: 21296765 PMCID: PMC3068001 DOI: 10.1093/gbe/evr008] [Citation(s) in RCA: 124] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The genome of maize (Zea mays ssp. mays) consists mostly of transposable elements (TEs) and varies in size among lines. This variation extends to other species in the genus Zea: although maize and Zea luxurians diverged only ∼140,000 years ago, their genomes differ in size by ∼50%. We used paired-end Illumina sequencing to evaluate the potential contribution of TEs to the genome size difference between these two species. We aligned the reads both to a filtered gene set and to an exemplar database of unique repeats representing 1,514 TE families; ∼85% of reads mapped against TE repeats in both species. The relative contribution of TE families to the B73 genome was highly correlated with previous estimates, suggesting that reliable estimates of TE content can be obtained from short high-throughput sequencing reads, even at low coverage. Because we used paired-end reads, we could assess whether a TE was near a gene by determining if one paired read mapped to a TE and the second read mapped to a gene. Using this method, Class 2 DNA elements were found significantly more often in genic regions than Class 1 RNA elements, but Class 1 elements were found more often near other TEs. Overall, we found that both Class 1 and 2 TE families account for ∼70% of the genome size difference between B73 and luxurians. Interestingly, the relative abundance of TE families was conserved between species (r = 0.97), suggesting genome-wide control of TE content rather than family-specific effects.
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Affiliation(s)
- Maud I Tenaillon
- CNRS, UMR de Génétique Végétale, INRA/CNRS/Univ Paris-Sud/AgroParisTech, Ferme du Moulon, Gif-sur-Yvette, France
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29
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Yang L, Takuno S, Waters ER, Gaut BS. Lowly expressed genes in Arabidopsis thaliana bear the signature of possible pseudogenization by promoter degradation. Mol Biol Evol 2010; 28:1193-203. [PMID: 21059790 DOI: 10.1093/molbev/msq298] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Pseudogenes are defined as nonfunctional DNA sequences with homology to functional protein-coding genes, and they typically contain nonfunctional mutations within the presumptive coding region. In theory, pseudogenes can also be caused by mutations in upstream regulatory regions, appearing as open reading frames with attenuated expression. In this study, we identified 1,939 annotated protein-coding genes with little evidence of expression in Arabidopsis thaliana and characterized their molecular evolutionary characteristics. On average, this set of genes was shorter than expressed genes and evolved with a 2-fold higher rate of nonsynonymous substitutions. The divergence of upstream sequences, based on ortholog comparisons to A. lyrata, was also higher than expressed genes, suggesting that these lowly expressed genes could be examples of pseudogenization by promoter disablement, often due to transposable element insertion. We complemented our empirical study by extending the models of Force et al. (Force A, Lynch M, Pickett FB, Amores A, Yan YL, Postlethwait J. 1999. Preservation of duplicate genes by complementary, degenerative mutations. Genetics 151:1531-1545.) to derive the probability of promoter disablements after gene duplication.
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Affiliation(s)
- Liang Yang
- Department of Ecology and Evolutionary Biology, University of California, Irvine, CA, USA
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30
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Oh DH, Dassanayake M, Haas JS, Kropornika A, Wright C, d'Urzo MP, Hong H, Ali S, Hernandez A, Lambert GM, Inan G, Galbraith DW, Bressan RA, Yun DJ, Zhu JK, Cheeseman JM, Bohnert HJ. Genome structures and halophyte-specific gene expression of the extremophile Thellungiella parvula in comparison with Thellungiella salsuginea (Thellungiella halophila) and Arabidopsis. PLANT PHYSIOLOGY 2010; 154:1040-52. [PMID: 20833729 PMCID: PMC2971586 DOI: 10.1104/pp.110.163923] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
The genome of Thellungiella parvula, a halophytic relative of Arabidopsis (Arabidopsis thaliana), is being assembled using Roche-454 sequencing. Analyses of a 10-Mb scaffold revealed synteny with Arabidopsis, with recombination and inversion and an uneven distribution of repeat sequences. T. parvula genome structure and DNA sequences were compared with orthologous regions from Arabidopsis and publicly available bacterial artificial chromosome sequences from Thellungiella salsuginea (previously Thellungiella halophila). The three-way comparison of sequences, from one abiotic stress-sensitive species and two tolerant species, revealed extensive sequence conservation and microcolinearity, but grouping Thellungiella species separately from Arabidopsis. However, the T. parvula segments are distinguished from their T. salsuginea counterparts by a pronounced paucity of repeat sequences, resulting in a 30% shorter DNA segment with essentially the same gene content in T. parvula. Among the genes is SALT OVERLY SENSITIVE1 (SOS1), a sodium/proton antiporter, which represents an essential component of plant salinity stress tolerance. Although the SOS1 coding region is highly conserved among all three species, the promoter regions show conservation only between the two Thellungiella species. Comparative transcript analyses revealed higher levels of basal as well as salt-induced SOS1 expression in both Thellungiella species as compared with Arabidopsis. The Thellungiella species and other halophytes share conserved pyrimidine-rich 5' untranslated region proximal regions of SOS1 that are missing in Arabidopsis. Completion of the genome structure of T. parvula is expected to highlight distinctive genetic elements underlying the extremophile lifestyle of this species.
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Affiliation(s)
- Dong-Ha Oh
- Department of Plant Biology , University of Illinois, Urbana, Illinois 61801, USA.
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31
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DeBolt S. Copy number variation shapes genome diversity in Arabidopsis over immediate family generational scales. Genome Biol Evol 2010; 2:441-53. [PMID: 20624746 PMCID: PMC2997553 DOI: 10.1093/gbe/evq033] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Arabidopsis thaliana is the model plant and is grown worldwide by plant biologists seeking to dissect the molecular underpinning of plant growth and development. Gene copy number variation (CNV) is a common form of genome natural diversity that is currently poorly studied in plants and may have broad implications for model organism research, evolutionary biology, and crop science. Herein, comparative genomic hybridization (CGH) was used to identify and interrogate regions of gene CNV across the A. thaliana genome. A common temperature condition used for growth of A. thaliana in our laboratory and many around the globe is 22 degrees C. The current study sought to test whether A. thaliana, grown under different temperature (16 and 28 degrees C) and stress regimes (salicylic acid spray) for five generations, selecting for fecundity at each generation, displayed any differences in CNV relative to a plant lineage growing under normal conditions. Three siblings from each alternative temperature or stress lineage were also compared with the reference genome (22 degrees C) by CGH to determine repetitive and nonrepetitive CNVs. Findings document exceptional rates of CNV in the genome of A. thaliana over immediate family generational scales. A propensity for duplication and nonrepetitive CNVs was documented in 28 degrees C CGH, which was correlated with the greatest plant stress and infers a potential CNV-environmental interaction. A broad diversity of gene species were observed within CNVs, but transposable elements and biotic stress response genes were notably overrepresented as a proportion of total genes and genes initiating CNVs. Results support a model whereby segmental CNV and the genes encoded within these regions contribute to adaptive capacity of plants through natural genome variation.
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Affiliation(s)
- Seth DeBolt
- Plant Physiology/Biochemistry/Molecular Biology Program, Department of Horticulture, University of Kentucky, USA.
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32
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Nah G, Jeffrey Chen Z. Tandem duplication of the FLC locus and the origin of a new gene in Arabidopsis related species and their functional implications in allopolyploids. THE NEW PHYTOLOGIST 2010; 186:228-38. [PMID: 20100201 DOI: 10.1111/j.1469-8137.2009.03164.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Flowering time is an important adaptive trait and varies among Arabidopsis thaliana and its related species, including allopolyploids that are formed between A. thaliana and Arabidopsis arenosa. FLOWERING LOCUS C (FLC) inhibits early flowering in A. thaliana. A previous study showed that late-flowering A. arenosa contained two or more FLC alleles that were differentially expressed in Arabidopsis allotetraploids, but the genomic organization and evolution of FLC locus were unknown. Comparative sequence and evolutionary analyses were performed in FLC-containing genomic regions in A. thaliana, A. arenosa and Arabidopsis lyrata, and expression of FLC loci and alleles was examined in Arabidopsis allopolyploids. The FLC locus was tandemly duplicated in A. lyrata and triplicated in A. arenosa, and the tandem duplication event occurred after divergence from A. thaliana. Although FLC duplicates were highly conserved, their upstream sequences rapidly diverged. The third FLC copy in A. arenosa acquired a new splicing site through a point mutation in the intron and generated the new exon followed by an early stop codon, resulting in a novel MADS box gene. Flowering time variation in Arabidopsis allopolyploids is probably related to the expression diversity and/or copy number of multiple FLC loci. Moreover, exonization of intronic sequence is a mechanism for the origin of new genes.
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Parisod C, Salmon A, Zerjal T, Tenaillon M, Grandbastien MA, Ainouche M. Rapid structural and epigenetic reorganization near transposable elements in hybrid and allopolyploid genomes in Spartina. THE NEW PHYTOLOGIST 2009; 184:1003-15. [PMID: 19780987 DOI: 10.1111/j.1469-8137.2009.03029.x] [Citation(s) in RCA: 149] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
*Transposable elements (TE) induce structural and epigenetic alterations in their host genome, with major evolutionary implications. These alterations are examined here in the context of allopolyploid speciation, on the recently formed invasive species Spartina anglica, which represents an excellent model to contrast plant genome dynamics following hybridization and genome doubling in natural conditions. *Methyl-sensitive transposon display was used to investigate the structural and epigenetic dynamics of TE insertion sites for several elements, and to contrast it with comparable genome-wide methyl-sensitive amplified polymorphism analyses. *While no transposition burst was detected, we found evidence of major structural and CpG methylation changes in the vicinity of TE insertions accompanying hybridization, and to a lesser extent, genome doubling. Genomic alteration appeared preferentially in the maternal subgenome, and the environment of TEs was specifically affected by large maternal-specific methylation changes, demonstrating that TEs fuel epigenetic alterations at the merging of diverged genomes. *Such genome changes indicate that nuclear incompatibilities in Spartina trigger immediate alterations, which are TE-specific with an important epigenetic component. Since most of this reorganization is conserved after genome doubling that produced a fertile invasive species, TEs certainly play a central role in the shock-induced dynamics of the genome during allopolyploid speciation.
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Affiliation(s)
- Christian Parisod
- Laboratoire de Biologie Cellulaire, Institut Jean-Pierre Bourgin, INRA, Versailles, France
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Tian Z, Rizzon C, Du J, Zhu L, Bennetzen JL, Jackson SA, Gaut BS, Ma J. Do genetic recombination and gene density shape the pattern of DNA elimination in rice long terminal repeat retrotransposons? Genome Res 2009; 19:2221-30. [PMID: 19789376 DOI: 10.1101/gr.083899.108] [Citation(s) in RCA: 116] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
In flowering plants, the accumulation of small deletions through unequal homologous recombination (UR) and illegitimate recombination (IR) is proposed to be the major process counteracting genome expansion, which is caused primarily by the periodic amplification of long terminal repeat retrotransposons (LTR-RTs). However, the full suite of evolutionary forces that govern the gain or loss of transposable elements (TEs) and their distribution within a genome remains unclear. Here, we investigated the distribution and structural variation of LTR-RTs in relation to the rates of local genetic recombination (GR) and gene densities in the rice (Oryza sativa) genome. Our data revealed a positive correlation between GR rates and gene densities and negative correlations between LTR-RT densities and both GR and gene densities. The data also indicate a tendency for LTR-RT elements and fragments to be shorter in regions with higher GR rates; the size reduction of LTR-RTs appears to be achieved primarily through solo LTR formation by UR. Comparison of indica and japonica rice revealed patterns and frequencies of LTR-RT gain and loss within different evolutionary timeframes. Different LTR-RT families exhibited variable distribution patterns and structural changes, but overall LTR-RT compositions and genes were organized according to the GR gradients of the genome. Further investigation of non-LTR-RTs and DNA transposons revealed a negative correlation between gene densities and the abundance of DNA transposons and a weak correlation between GR rates and the abundance of long interspersed nuclear elements (LINEs)/short interspersed nuclear elements (SINEs). Together, these observations suggest that GR and gene density play important roles in shaping the dynamic structure of the rice genome.
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Affiliation(s)
- Zhixi Tian
- Department of Agronomy, Purdue University, West Lafayette, Indiana 47907, USA
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Worden AZ, Lee JH, Mock T, Rouzé P, Simmons MP, Aerts AL, Allen AE, Cuvelier ML, Derelle E, Everett MV, Foulon E, Grimwood J, Gundlach H, Henrissat B, Napoli C, McDonald SM, Parker MS, Rombauts S, Salamov A, Von Dassow P, Badger JH, Coutinho PM, Demir E, Dubchak I, Gentemann C, Eikrem W, Gready JE, John U, Lanier W, Lindquist EA, Lucas S, Mayer KFX, Moreau H, Not F, Otillar R, Panaud O, Pangilinan J, Paulsen I, Piegu B, Poliakov A, Robbens S, Schmutz J, Toulza E, Wyss T, Zelensky A, Zhou K, Armbrust EV, Bhattacharya D, Goodenough UW, Van de Peer Y, Grigoriev IV. Green evolution and dynamic adaptations revealed by genomes of the marine picoeukaryotes Micromonas. Science 2009; 324:268-72. [PMID: 19359590 DOI: 10.1126/science.1167222] [Citation(s) in RCA: 416] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Picoeukaryotes are a taxonomically diverse group of organisms less than 2 micrometers in diameter. Photosynthetic marine picoeukaryotes in the genus Micromonas thrive in ecosystems ranging from tropical to polar and could serve as sentinel organisms for biogeochemical fluxes of modern oceans during climate change. These broadly distributed primary producers belong to an anciently diverged sister clade to land plants. Although Micromonas isolates have high 18S ribosomal RNA gene identity, we found that genomes from two isolates shared only 90% of their predicted genes. Their independent evolutionary paths were emphasized by distinct riboswitch arrangements as well as the discovery of intronic repeat elements in one isolate, and in metagenomic data, but not in other genomes. Divergence appears to have been facilitated by selection and acquisition processes that actively shape the repertoire of genes that are mutually exclusive between the two isolates differently than the core genes. Analyses of the Micromonas genomes offer valuable insights into ecological differentiation and the dynamic nature of early plant evolution.
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Feng J, Naiman DQ, Cooper B. Coding DNA repeated throughout intergenic regions of the Arabidopsis thaliana genome: evolutionary footprints of RNA silencing. MOLECULAR BIOSYSTEMS 2009; 5:1679-87. [PMID: 19452047 DOI: 10.1039/b903031j] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Pyknons are non-random sequence patterns significantly repeated throughout non-coding genomic DNA that also appear at least once among coding genes. They are interesting because they portend an unforeseen connection between coding and non-coding DNA. Pyknons have only been discovered in the human genome, so it is unknown whether pyknons have wider biological relevance or are simply a phenomenon of the human genome. To address this, DNA sequence patterns from the Arabidopsis thaliana genome were detected using a probability-based method. 24 654 statistically significant sequence patterns, 16 to 24 nucleotides long, repeating 10 or more times in non-coding DNA also appeared in 46% of A. thaliana protein-coding genes. A. thaliana pyknons exhibit features similar to human pyknons, including being distinct sequence patterns, having multiple instances in genes and having remarkable similarity to small RNA sequences with roles in gene silencing. Chromosomal position mapping revealed that genomic pyknon density has concordance with siRNA and transposable element positioning density. Because the A. thaliana and human genomes have approximately the same number of genes but drastically different amounts of non-coding DNA, these data reveal that pyknons represent a biologically important link between coding and non-coding DNA. Because of the association of pyknons with siRNAs and localization to silenced regions of heterochromatin, we postulate that RNA-mediated gene silencing leads to the accumulation of gene sequences in non-coding DNA regions.
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Affiliation(s)
- Jian Feng
- Department of Applied Mathematics and Statistics, The Johns Hopkins University, Baltimore, MD 21218, USA
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Piednoël M, Bonnivard E. DIRS1-like retrotransposons are widely distributed among Decapoda and are particularly present in hydrothermal vent organisms. BMC Evol Biol 2009; 9:86. [PMID: 19400949 PMCID: PMC2685390 DOI: 10.1186/1471-2148-9-86] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2008] [Accepted: 04/28/2009] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND Transposable elements are major constituents of eukaryote genomes and have a great impact on genome structure and stability. Considering their mutational abilities, TEs can contribute to the genetic diversity and evolution of organisms. Knowledge of their distribution among several genomes is an essential condition to study their dynamics and to better understand their role in species evolution. DIRS1-like retrotransposons are a particular group of retrotransposons according to their mode of transposition that implies a tyrosine recombinase. To date, they have been described in a restricted number of species in comparison with the LTR retrotransposons. In this paper, we determine the distribution of DIRS1-like elements among 25 decapod species, 10 of them living in hydrothermal vents that correspond to particularly unstable environments. RESULTS Using PCR approaches, we have identified 15 new DIRS1-like families in 15 diverse decapod species (shrimps, lobsters, crabs and galatheid crabs). Hydrothermal organisms show a particularly great diversity of DIRS1-like elements with 5 families characterized among Alvinocarididae shrimps and 3 in the galatheid crab Munidopsis recta. Phylogenic analyses show that these elements are divergent toward the DIRS1-like families previously described in other crustaceans and arthropods and form a new clade called AlDIRS1. At larger scale, the distribution of DIRS1-like retrotransposons appears more or less patchy depending on the taxa considered. Indeed, a scattered distribution can be observed in the infraorder Brachyura whereas all the species tested in infraorders Caridea and Astacidea harbor some DIRS1-like elements. CONCLUSION Our results lead to nearly double both the number of DIRS1-like elements described to date, and the number of species known to harbor these ones. In this study, we provide the first degenerate primers designed to look specifically for DIRS1-like retrotransposons. They allowed for revealing for the first time a widespread distribution of these elements among a large phylum, here the order Decapoda. They also suggest some peculiar features of these retrotransposons in hydrothermal organisms where a great diversity of elements is already observed. Finally, this paper constitutes the first essential step which allows for considering further studies based on the dynamics of the DIRS1-like retrotransposons among several genomes.
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Affiliation(s)
- Mathieu Piednoël
- UMR 7138 Systématique Adaptation Evolution, Equipe Génétique et Evolution, Université Pierre et Marie Curie Paris 6, Case 5, Bâtiment A, porte 427, 7 quai St Bernard, 75252 Paris Cedex 05, France
| | - Eric Bonnivard
- UMR 7138 Systématique Adaptation Evolution, Equipe Génétique et Evolution, Université Pierre et Marie Curie Paris 6, Case 5, Bâtiment A, porte 427, 7 quai St Bernard, 75252 Paris Cedex 05, France
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Duplicate gene evolution toward multiple fates at the Drosophila melanogaster HIP/HIP-Replacement locus. J Mol Evol 2009; 68:337-50. [PMID: 19333534 DOI: 10.1007/s00239-009-9213-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2008] [Revised: 02/10/2009] [Accepted: 02/16/2009] [Indexed: 10/20/2022]
Abstract
Hsc/Hsp70-interacting protein (HIP) is a rapidly evolving Hsp70 cofactor. Analyses of multiple Drosophila species indicate that the HIP gene is duplicated only in D. melanogaster. The HIP region, in fact, contains seven distinctly evolving duplicated genes. The regional duplication occurred in two steps, fixed rapidly, and illustrates multiple modes of duplicate gene evolution. HIP and its duplicate HIP-R are adaptively evolving in a manner unique to the region: they exhibit elevated divergence from other drosophilids and low polymorphism within D. melanogaster. HIP and HIP-R are virtually identical, share polymorphisms, and are subject to gene conversion. In contrast, two other duplicate genes in the region, CG33221 and GP-CG32779, are pseudogenes, and the chimeric gene Crg1 is subject to balancing selection. HIP and HIP-R are evolving rapidly and adaptively; however, positive selection is not sufficient to explain the molecular evolution of the region as a whole.
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The evolution of plant genomes: scaling up from a population perspective. Curr Opin Genet Dev 2009; 18:565-70. [PMID: 19131240 DOI: 10.1016/j.gde.2008.11.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2008] [Revised: 11/14/2008] [Accepted: 11/18/2008] [Indexed: 02/02/2023]
Abstract
Plant genomes exhibit tremendous diversity in both their size and structure, with genome sizes across land plants ranging over two to three orders of magnitude and significant variation in structural organization was observed across species (EA Kellogg, JL Bennetzen, The evolution of nuclear genome structure in seed plants, Am J Bot 2004, 91:1709-1725). Five plant genomes are now either completely sequenced or in the draft stage; the grape (O Jaillon et al., The grapevine genome sequence suggests ancestral hexaploidization in major angiosperm phyla, Nature 2007, 449:463-467) and papaya (R Ming et al., The draft genome of the transgenic tropical fruit tree papaya (Carica papaya Linnaeus), Nature 2008, 452:991-997) whole genome sequences were reported most recently. Moreover, sequencing of 41 additional genomes is in progress. There is now an emerging consensus that understanding genome evolution requires consideration of the population genetics of genome diversification, and that description of evolutionary forces at the level of populations and within species can help identify the features that led to plant genome diversity (M Lynch, JS Conery, The origins of genome complexity, Science 2003, 302:1401-1404). In this review we focus on advances in our understanding of the mechanisms that drive the diversification of genomes. In particular, we look at the extent to which demographic features such as effective population size changes within species can drive genome evolution, discuss population genetic models of genome diversification associated with transposable element (TE) mobilization, and describe recent studies on the evolution of gene families.
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Fan C, Zhang Y, Yu Y, Rounsley S, Long M, Wing RA. The subtelomere of Oryza sativa chromosome 3 short arm as a hot bed of new gene origination in rice. MOLECULAR PLANT 2008; 1:839-50. [PMID: 19825586 PMCID: PMC2902912 DOI: 10.1093/mp/ssn050] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2008] [Accepted: 07/15/2008] [Indexed: 05/22/2023]
Abstract
Despite general observations of non-random genomic distribution of new genes, it is unclear whether or not new genes preferentially occur in certain genomic regions driven by related molecular mechanisms. Using 1.5 Mb of genomic sequences from short arms of chromosome 3 of Oryza glaberrima and O. punctata, we conducted a comparative genomic analysis with the reference O. sativa ssp. japonica genome. We identified a 60-kb segment located in the middle of the subtelomeric region of chromosome 3, which is unique to the species O. sativa. The region contained gene duplicates that occurred in Asian cultivated rice species that diverged from the ancestor of Asian and African cultivated rice one million years ago (MYA). For the 12 genes and one complete retrotransposon identified in this segment in O. sativa ssp. japonica, we searched for their parental genes. The high similarity between duplicated paralogs further supports the recent origination of these genes. We found that this segment was recently generated through multiple independent gene recombination and transposon insertion events. Among the 12 genes, we found that five had chimeric gene structures derived from multiple parental genes. Nine out of the 12 new genes seem to be functional, as suggested by Ka/Ks analysis and the presence of cDNA and/or MPSS data. Furthermore, for the eight transcribed genes, at least two genes could be classified as defense or stress response-related genes. Given these findings, and the fact that subtelomeres are associated with high rates of recombination and transcription, it is likely that subtelomeres may facilitate gene recombination and transposon insertions and serve as hot spots for new gene origination in rice genomes.
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Affiliation(s)
- Chuanzhu Fan
- Arizona Genomics Institute, Department of Plant Sciences, University of Arizona, Tucson, AZ 85721, USA
| | - Yong Zhang
- Department of Ecology and Evolution, University of Chicago, Chicago, IL 60637, USA
| | - Yeisoo Yu
- Arizona Genomics Institute, Department of Plant Sciences, University of Arizona, Tucson, AZ 85721, USA
| | - Steve Rounsley
- BIO5 Institute for Collaborative Research, University of Arizona, Tucson, AZ 85721, USA
| | - Manyuan Long
- Department of Ecology and Evolution, University of Chicago, Chicago, IL 60637, USA
- To whom correspondence should be addressed. E-mail , fax 773-702-9740, tel. 773-702-0557. E-mail , fax 520-621-1259, tel. 520-626-9595
| | - Rod A. Wing
- Arizona Genomics Institute, Department of Plant Sciences, University of Arizona, Tucson, AZ 85721, USA
- To whom correspondence should be addressed. E-mail , fax 773-702-9740, tel. 773-702-0557. E-mail , fax 520-621-1259, tel. 520-626-9595
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