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Geck RC, Moresi NG, Anderson LM, Brewer R, Renz TR, Taylor MB, Dunham MJ. Experimental evolution of Saccharomyces cerevisiae for caffeine tolerance alters multidrug resistance and target of rapamycin signaling pathways. G3 (BETHESDA, MD.) 2024; 14:jkae148. [PMID: 38989875 PMCID: PMC11373655 DOI: 10.1093/g3journal/jkae148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2024] [Revised: 06/29/2024] [Accepted: 07/01/2024] [Indexed: 07/12/2024]
Abstract
Caffeine is a natural compound that inhibits the major cellular signaling regulator target of rapamycin (TOR), leading to widespread effects including growth inhibition. Saccharomyces cerevisiae yeast can adapt to tolerate high concentrations of caffeine in coffee and cacao fermentations and in experimental systems. While many factors affecting caffeine tolerance and TOR signaling have been identified, further characterization of their interactions and regulation remain to be studied. We used experimental evolution of S. cerevisiae to study the genetic contributions to caffeine tolerance in yeast, through a collaboration between high school students evolving yeast populations coupled with further research exploration in university labs. We identified multiple evolved yeast populations with mutations in PDR1 and PDR5, which contribute to multidrug resistance, and showed that gain-of-function mutations in multidrug resistance family transcription factors Pdr1, Pdr3, and Yrr1 differentially contribute to caffeine tolerance. We also identified loss-of-function mutations in TOR effectors Sit4, Sky1, and Tip41 and showed that these mutations contribute to caffeine tolerance. These findings support the importance of both the multidrug resistance family and TOR signaling in caffeine tolerance and can inform future exploration of networks affected by caffeine and other TOR inhibitors in model systems and industrial applications.
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Affiliation(s)
- Renee C Geck
- Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA
| | - Naomi G Moresi
- Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA
| | - Leah M Anderson
- Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA
| | | | | | | | - Maitreya J Dunham
- Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA
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2
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Huang HY, Zhang S, Choucha FA, Verdenaud M, Tan FQ, Pichot C, Parsa HS, Slavkovic F, Chen Q, Troadec C, Marcel F, Dogimont C, Quadrana L, Boualem A, Bendahmane A. Harbinger transposon insertion in ethylene signaling gene leads to emergence of new sexual forms in cucurbits. Nat Commun 2024; 15:4877. [PMID: 38849342 PMCID: PMC11161486 DOI: 10.1038/s41467-024-49250-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Accepted: 05/28/2024] [Indexed: 06/09/2024] Open
Abstract
In flowering plants, the predominant sexual morph is hermaphroditism, and the emergence of unisexuality is poorly understood. Using Cucumis melo (melon) as a model system, we explore the mechanisms driving sexual forms. We identify a spontaneous mutant exhibiting a transition from bisexual to unisexual male flower, and identify the causal mutation as a Harbinger transposon impairing the expression of Ethylene Insensitive 2 (CmEIN2) gene. Genetics and transcriptomic analysis reveal a dual role of CmEIN2 in both sex determination and fruit shape formation. Upon expression of CmACS11, EIN2 is recruited to repress the expression of the carpel inhibitor, CmWIP1. Subsequently, EIN2 is recruited to mediate stamina inhibition. Following the sex determination phase, EIN2 promotes fruit shape elongation. Genome-wide analysis reveals that Harbinger transposon mobilization is triggered by environmental cues, and integrates preferentially in active chromatin, particularly within promoter regions. Characterization of a large collection of melon germplasm points to active transpositions in the wild, compared to cultivated accessions. Our study underscores the association between chromatin dynamics and the temporal aspects of mobile genetic element insertions, providing valuable insights into plant adaptation and crop genome evolution.
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Affiliation(s)
- Hsin-Ya Huang
- Université Paris-Saclay, CNRS, INRAE, Université Evry, Institute of Plant Sciences Paris-Saclay (IPS2), 91190, Gif-sur-Yvette, France
| | - Siqi Zhang
- Université Paris-Saclay, CNRS, INRAE, Université Evry, Institute of Plant Sciences Paris-Saclay (IPS2), 91190, Gif-sur-Yvette, France
| | - Fadi Abou Choucha
- Université Paris-Saclay, CNRS, INRAE, Université Evry, Institute of Plant Sciences Paris-Saclay (IPS2), 91190, Gif-sur-Yvette, France
| | - Marion Verdenaud
- Université Paris-Saclay, CNRS, INRAE, Université Evry, Institute of Plant Sciences Paris-Saclay (IPS2), 91190, Gif-sur-Yvette, France
| | - Feng-Quan Tan
- Université Paris-Saclay, CNRS, INRAE, Université Evry, Institute of Plant Sciences Paris-Saclay (IPS2), 91190, Gif-sur-Yvette, France
| | - Clement Pichot
- Université Paris-Saclay, CNRS, INRAE, Université Evry, Institute of Plant Sciences Paris-Saclay (IPS2), 91190, Gif-sur-Yvette, France
| | - Hadi Shirazi Parsa
- Université Paris-Saclay, CNRS, INRAE, Université Evry, Institute of Plant Sciences Paris-Saclay (IPS2), 91190, Gif-sur-Yvette, France
| | - Filip Slavkovic
- Université Paris-Saclay, CNRS, INRAE, Université Evry, Institute of Plant Sciences Paris-Saclay (IPS2), 91190, Gif-sur-Yvette, France
| | - Qinghe Chen
- Université Paris-Saclay, CNRS, INRAE, Université Evry, Institute of Plant Sciences Paris-Saclay (IPS2), 91190, Gif-sur-Yvette, France
| | - Christelle Troadec
- Université Paris-Saclay, CNRS, INRAE, Université Evry, Institute of Plant Sciences Paris-Saclay (IPS2), 91190, Gif-sur-Yvette, France
| | - Fabien Marcel
- Université Paris-Saclay, CNRS, INRAE, Université Evry, Institute of Plant Sciences Paris-Saclay (IPS2), 91190, Gif-sur-Yvette, France
| | - Catherine Dogimont
- INRAE, Génétique et Amélioration des Fruits et Légumes (GAFL), 84143, Montfavet, France
| | - Leandro Quadrana
- Université Paris-Saclay, CNRS, INRAE, Université Evry, Institute of Plant Sciences Paris-Saclay (IPS2), 91190, Gif-sur-Yvette, France
| | - Adnane Boualem
- Université Paris-Saclay, CNRS, INRAE, Université Evry, Institute of Plant Sciences Paris-Saclay (IPS2), 91190, Gif-sur-Yvette, France
| | - Abdelhafid Bendahmane
- Université Paris-Saclay, CNRS, INRAE, Université Evry, Institute of Plant Sciences Paris-Saclay (IPS2), 91190, Gif-sur-Yvette, France.
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3
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Geck RC, Moresi NG, Anderson LM, Brewer R, Renz TR, Taylor MB, Dunham MJ. Experimental evolution of S. cerevisiae for caffeine tolerance alters multidrug resistance and TOR signaling pathways. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.28.591555. [PMID: 38746122 PMCID: PMC11092465 DOI: 10.1101/2024.04.28.591555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Caffeine is a natural compound that inhibits the major cellular signaling regulator TOR, leading to widespread effects including growth inhibition. S. cerevisiae yeast can adapt to tolerate high concentrations of caffeine in coffee and cacao fermentations and in experimental systems. While many factors affecting caffeine tolerance and TOR signaling have been identified, further characterization of their interactions and regulation remain to be studied. We used experimental evolution of S. cerevisiae to study the genetic contributions to caffeine tolerance in yeast, through a collaboration between high school students evolving yeast populations coupled with further research exploration in university labs. We identified multiple evolved yeast populations with mutations in PDR1 and PDR5, which contribute to multidrug resistance, and showed that gain-of-function mutations in multidrug resistance family transcription factors PDR1, PDR3, and YRR1 differentially contribute to caffeine tolerance. We also identified loss-of-function mutations in TOR effectors SIT4, SKY1, and TIP41, and show that these mutations contribute to caffeine tolerance. These findings support the importance of both the multidrug resistance family and TOR signaling in caffeine tolerance, and can inform future exploration of networks affected by caffeine and other TOR inhibitors in model systems and industrial applications.
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Affiliation(s)
- Renee C Geck
- Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA
| | - Naomi G Moresi
- Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA
| | - Leah M Anderson
- Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA
| | | | | | - M Bryce Taylor
- Program in Biology, Loras College, Dubuque, IA 52001, USA
| | - Maitreya J Dunham
- Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA
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4
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Rudenko V, Korotkov E. Study of Dispersed Repeats in the Cyanidioschyzon merolae Genome. Int J Mol Sci 2024; 25:4441. [PMID: 38674025 PMCID: PMC11050394 DOI: 10.3390/ijms25084441] [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] [Received: 02/19/2024] [Revised: 04/08/2024] [Accepted: 04/15/2024] [Indexed: 04/28/2024] Open
Abstract
In this study, we applied the iterative procedure (IP) method to search for families of highly diverged dispersed repeats in the genome of Cyanidioschyzon merolae, which contains over 16 million bases. The algorithm included the construction of position weight matrices (PWMs) for repeat families and the identification of more dispersed repeats based on the PWMs using dynamic programming. The results showed that the C. merolae genome contained 20 repeat families comprising a total of 33,938 dispersed repeats, which is significantly more than has been previously found using other methods. The repeats varied in length from 108 to 600 bp (522.54 bp in average) and occupied more than 72% of the C. merolae genome, whereas previously identified repeats, including tandem repeats, have been shown to constitute only about 28%. The high genomic content of dispersed repeats and their location in the coding regions suggest a significant role in the regulation of the functional activity of the genome.
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Affiliation(s)
- Valentina Rudenko
- Institute of Bioengineering, Research Center of Biotechnology of the Russian Academy of Sciences, Moscow 119071, Russia;
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5
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Abraham LN, Oggenfuss U, Croll D. Population-level transposable element expression dynamics influence trait evolution in a fungal crop pathogen. mBio 2024; 15:e0284023. [PMID: 38349152 PMCID: PMC10936205 DOI: 10.1128/mbio.02840-23] [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] [Received: 10/20/2023] [Accepted: 01/22/2024] [Indexed: 03/14/2024] Open
Abstract
The rapid adaptive evolution of microbes is driven by strong selection pressure acting on genetic variation. How adaptive genetic variation is generated within species and how such variation influences phenotypic trait expression is often not well understood though. We focused on the recent activity of transposable elements (TEs) using deep population genomics and transcriptomics analyses of a fungal plant pathogen with a highly active content of TEs in the genome. Zymoseptoria tritici causes one of the most damaging diseases on wheat, with recent adaptation to the host and environment being facilitated by TE-associated mutations. We obtained genomic and RNA-sequencing data from 146 isolates collected from a single wheat field. We established a genome-wide map of TE insertion polymorphisms in the population by analyzing recent TE insertions among individuals. We quantified the locus-specific transcription of individual TE copies and found considerable population variation at individual TE loci in the population. About 20% of all TE copies show transcription in the genome suggesting that genomic defenses such as repressive epigenetic marks and repeat-induced polymorphisms are at least partially ineffective at preventing the proliferation of TEs in the genome. A quarter of recent TE insertions are associated with expression variation of neighboring genes providing broad potential to influence trait expression. We indeed found that TE insertions are likely responsible for variation in virulence on the host and potentially diverse components of secondary metabolite production. Our large-scale transcriptomics study emphasizes how TE-derived polymorphisms segregate even in individual microbial populations and can broadly underpin trait variation in pathogens.IMPORTANCEPathogens can rapidly adapt to new hosts, antimicrobials, or changes in the environment. Adaptation arises often from mutations in the genome; however, how such variation is generated remains poorly understood. We investigated the most dynamic regions of the genome of Zymoseptoria tritici, a major fungal pathogen of wheat. We focused on the transcription of transposable elements. A large proportion of the transposable elements not only show signatures of potential activity but are also variable within a single population of the pathogen. We find that this variation in activity is likely influencing many important traits of the pathogen. Hence, our work provides insights into how a microbial species can adapt over the shortest time periods based on the activity of transposable elements.
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Affiliation(s)
- Leen Nanchira Abraham
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Ursula Oggenfuss
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Daniel Croll
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
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6
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Wijngaard R, Demidov G, O'Gorman L, Corominas-Galbany J, Yaldiz B, Steyaert W, de Boer E, Vissers LELM, Kamsteeg EJ, Pfundt R, Swinkels H, den Ouden A, Te Paske IBAW, de Voer RM, Faivre L, Denommé-Pichon AS, Duffourd Y, Vitobello A, Chevarin M, Straub V, Töpf A, van der Kooi AJ, Magrinelli F, Rocca C, Hanna MG, Vandrovcova J, Ossowski S, Laurie S, Gilissen C. Mobile element insertions in rare diseases: a comparative benchmark and reanalysis of 60,000 exome samples. Eur J Hum Genet 2024; 32:200-208. [PMID: 37853102 PMCID: PMC10853235 DOI: 10.1038/s41431-023-01478-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 08/29/2023] [Accepted: 10/04/2023] [Indexed: 10/20/2023] Open
Abstract
Mobile element insertions (MEIs) are a known cause of genetic disease but have been underexplored due to technical limitations of genetic testing methods. Various bioinformatic tools have been developed to identify MEIs in Next Generation Sequencing data. However, most tools have been developed specifically for genome sequencing (GS) data rather than exome sequencing (ES) data, which remains more widely used for routine diagnostic testing. In this study, we benchmarked six MEI detection tools (ERVcaller, MELT, Mobster, SCRAMble, TEMP2 and xTea) on ES data and on GS data from publicly available genomic samples (HG002, NA12878). For all the tools we evaluated sensitivity and precision of different filtering strategies. Results show that there were substantial differences in tool performance between ES and GS data. MELT performed best with ES data and its combination with SCRAMble increased substantially the detection rate of MEIs. By applying both tools to 10,890 ES samples from Solve-RD and 52,624 samples from Radboudumc we were able to diagnose 10 patients who had remained undiagnosed by conventional ES analysis until now. Our study shows that MELT and SCRAMble can be used reliably to identify clinically relevant MEIs in ES data. This may lead to an additional diagnosis for 1 in 3000 to 4000 patients in routine clinical ES.
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Affiliation(s)
- Robin Wijngaard
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands
| | - German Demidov
- Universitätsklinikum Tübingen - Institut für Medizinische Genetik und angewandte Genomik, Tübingen, Germany
| | - Luke O'Gorman
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | | | - Burcu Yaldiz
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Wouter Steyaert
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
- Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Elke de Boer
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands
| | - Lisenka E L M Vissers
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands
| | - Erik-Jan Kamsteeg
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands
| | - Rolph Pfundt
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Hilde Swinkels
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Amber den Ouden
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Iris B A W Te Paske
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
- Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Richarda M de Voer
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
- Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Laurence Faivre
- Centre de Référence Maladies Rares "Anomalies du développement et syndromes malformatifs", Centre de Génétique, FHU-TRANSLAD et Institut GIMI, CHU Dijon Bourgogne, Dijon, France
| | - Anne-Sophie Denommé-Pichon
- UMR1231-Inserm, Génétique des Anomalies du développement, Université de Bourgogne Franche-Comté, Dijon, France
- Laboratoire de Génétique chromosomique et moléculaire, UF6254 Innovation en diagnostic génomique des maladies rares, Centre Hospitalier Universitaire de Dijon, Dijon, France
| | - Yannis Duffourd
- UMR1231-Inserm, Génétique des Anomalies du développement, Université de Bourgogne Franche-Comté, Dijon, France
- Laboratoire de Génétique chromosomique et moléculaire, UF6254 Innovation en diagnostic génomique des maladies rares, Centre Hospitalier Universitaire de Dijon, Dijon, France
| | - Antonio Vitobello
- UMR1231-Inserm, Génétique des Anomalies du développement, Université de Bourgogne Franche-Comté, Dijon, France
- Laboratoire de Génétique chromosomique et moléculaire, UF6254 Innovation en diagnostic génomique des maladies rares, Centre Hospitalier Universitaire de Dijon, Dijon, France
| | - Martin Chevarin
- UMR1231-Inserm, Génétique des Anomalies du développement, Université de Bourgogne Franche-Comté, Dijon, France
- Laboratoire de Génétique chromosomique et moléculaire, UF6254 Innovation en diagnostic génomique des maladies rares, Centre Hospitalier Universitaire de Dijon, Dijon, France
| | - Volker Straub
- John Walton Muscular Dystrophy Research Centre, Translational and Clinical Research Institute, Newcastle University and Newcastle Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
| | - Ana Töpf
- John Walton Muscular Dystrophy Research Centre, Translational and Clinical Research Institute, Newcastle University and Newcastle Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
| | - Anneke J van der Kooi
- Department of Neurology, Amsterdam UMC, University of Amsterdam, Amsterdam Neuroscience, Amsterdam, The Netherlands
| | - Francesca Magrinelli
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London, UK
| | - Clarissa Rocca
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK
- Clinical Pharmacology, William Harvey Research Institute, School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Michael G Hanna
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK
| | - Jana Vandrovcova
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK
| | - Stephan Ossowski
- Universitätsklinikum Tübingen - Institut für Medizinische Genetik und angewandte Genomik, Tübingen, Germany
| | - Steven Laurie
- Centro Nacional de Análisis Genómico (CNAG), Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
| | - Christian Gilissen
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.
- Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands.
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Chen J, Basting PJ, Han S, Garfinkel DJ, Bergman CM. Reproducible evaluation of transposable element detectors with McClintock 2 guides accurate inference of Ty insertion patterns in yeast. Mob DNA 2023; 14:8. [PMID: 37452430 PMCID: PMC10347736 DOI: 10.1186/s13100-023-00296-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Accepted: 06/09/2023] [Indexed: 07/18/2023] Open
Abstract
BACKGROUND Many computational methods have been developed to detect non-reference transposable element (TE) insertions using short-read whole genome sequencing data. The diversity and complexity of such methods often present challenges to new users seeking to reproducibly install, execute, or evaluate multiple TE insertion detectors. RESULTS We previously developed the McClintock meta-pipeline to facilitate the installation, execution, and evaluation of six first-generation short-read TE detectors. Here, we report a completely re-implemented version of McClintock written in Python using Snakemake and Conda that improves its installation, error handling, speed, stability, and extensibility. McClintock 2 now includes 12 short-read TE detectors, auxiliary pre-processing and analysis modules, interactive HTML reports, and a simulation framework to reproducibly evaluate the accuracy of component TE detectors. When applied to the model microbial eukaryote Saccharomyces cerevisiae, we find substantial variation in the ability of McClintock 2 components to identify the precise locations of non-reference TE insertions, with RelocaTE2 showing the highest recall and precision in simulated data. We find that RelocaTE2, TEMP, TEMP2 and TEBreak provide consistent estimates of [Formula: see text]50 non-reference TE insertions per strain and that Ty2 has the highest number of non-reference TE insertions in a species-wide panel of [Formula: see text]1000 yeast genomes. Finally, we show that best-in-class predictors for yeast applied to resequencing data have sufficient resolution to reveal a dyad pattern of integration in nucleosome-bound regions upstream of yeast tRNA genes for Ty1, Ty2, and Ty4, allowing us to extend knowledge about fine-scale target preferences revealed previously for experimentally-induced Ty1 insertions to spontaneous insertions for other copia-superfamily retrotransposons in yeast. CONCLUSION McClintock ( https://github.com/bergmanlab/mcclintock/ ) provides a user-friendly pipeline for the identification of TEs in short-read WGS data using multiple TE detectors, which should benefit researchers studying TE insertion variation in a wide range of different organisms. Application of the improved McClintock system to simulated and empirical yeast genome data reveals best-in-class methods and novel biological insights for one of the most widely-studied model eukaryotes and provides a paradigm for evaluating and selecting non-reference TE detectors in other species.
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Affiliation(s)
- Jingxuan Chen
- Institute of Bioinformatics, University of Georgia, Athens, GA USA
| | | | - Shunhua Han
- Institute of Bioinformatics, University of Georgia, Athens, GA USA
| | - David J. Garfinkel
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA USA
| | - Casey M. Bergman
- Institute of Bioinformatics, University of Georgia, Athens, GA USA
- Department of Genetics, University of Georgia, Athens, GA USA
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8
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Hays M, Schwartz K, Schmidtke DT, Aggeli D, Sherlock G. Paths to adaptation under fluctuating nitrogen starvation: The spectrum of adaptive mutations in Saccharomyces cerevisiae is shaped by retrotransposons and microhomology-mediated recombination. PLoS Genet 2023; 19:e1010747. [PMID: 37192196 PMCID: PMC10218751 DOI: 10.1371/journal.pgen.1010747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 05/26/2023] [Accepted: 04/14/2023] [Indexed: 05/18/2023] Open
Abstract
There are many mechanisms that give rise to genomic change: while point mutations are often emphasized in genomic analyses, evolution acts upon many other types of genetic changes that can result in less subtle perturbations. Changes in chromosome structure, DNA copy number, and novel transposon insertions all create large genomic changes, which can have correspondingly large impacts on phenotypes and fitness. In this study we investigate the spectrum of adaptive mutations that arise in a population under consistently fluctuating nitrogen conditions. We specifically contrast these adaptive alleles and the mutational mechanisms that create them, with mechanisms of adaptation under batch glucose limitation and constant selection in low, non-fluctuating nitrogen conditions to address if and how selection dynamics influence the molecular mechanisms of evolutionary adaptation. We observe that retrotransposon activity accounts for a substantial number of adaptive events, along with microhomology-mediated mechanisms of insertion, deletion, and gene conversion. In addition to loss of function alleles, which are often exploited in genetic screens, we identify putative gain of function alleles and alleles acting through as-of-yet unclear mechanisms. Taken together, our findings emphasize that how selection (fluctuating vs. non-fluctuating) is applied also shapes adaptation, just as the selective pressure (nitrogen vs. glucose) does itself. Fluctuating environments can activate different mutational mechanisms, shaping adaptive events accordingly. Experimental evolution, which allows a wider array of adaptive events to be assessed, is thus a complementary approach to both classical genetic screens and natural variation studies to characterize the genotype-to-phenotype-to-fitness map.
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Affiliation(s)
- Michelle Hays
- Department of Genetics, Stanford University School of Medicine, Stanford, California, United States of America
| | - Katja Schwartz
- Department of Genetics, Stanford University School of Medicine, Stanford, California, United States of America
| | - Danica T. Schmidtke
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, United States of America
| | - Dimitra Aggeli
- Department of Genetics, Stanford University School of Medicine, Stanford, California, United States of America
| | - Gavin Sherlock
- Department of Genetics, Stanford University School of Medicine, Stanford, California, United States of America
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9
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Mohamed M, Sabot F, Varoqui M, Mugat B, Audouin K, Pélisson A, Fiston-Lavier AS, Chambeyron S. TrEMOLO: accurate transposable element allele frequency estimation using long-read sequencing data combining assembly and mapping-based approaches. Genome Biol 2023; 24:63. [PMID: 37013657 PMCID: PMC10069131 DOI: 10.1186/s13059-023-02911-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 03/23/2023] [Indexed: 04/05/2023] Open
Abstract
Transposable Element MOnitoring with LOng-reads (TrEMOLO) is a new software that combines assembly- and mapping-based approaches to robustly detect genetic elements called transposable elements (TEs). Using high- or low-quality genome assemblies, TrEMOLO can detect most TE insertions and deletions and estimate their allele frequency in populations. Benchmarking with simulated data revealed that TrEMOLO outperforms other state-of-the-art computational tools. TE detection and frequency estimation by TrEMOLO were validated using simulated and experimental datasets. Therefore, TrEMOLO is a comprehensive and suitable tool to accurately study TE dynamics. TrEMOLO is available under GNU GPL3.0 at https://github.com/DrosophilaGenomeEvolution/TrEMOLO .
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Affiliation(s)
- Mourdas Mohamed
- Institute of Human Genetics, UMR9002, CNRS and Université de Montpellier, Montpellier, France
| | - François Sabot
- DIADE, University of Montpellier, CIRAD, IRD, Montpellier, France
- IFB - Southgreen Bioversity, CIRAD, INRAE, IRD, Montpellier, France
| | - Marion Varoqui
- Institute of Human Genetics, UMR9002, CNRS and Université de Montpellier, Montpellier, France
| | - Bruno Mugat
- Institute of Human Genetics, UMR9002, CNRS and Université de Montpellier, Montpellier, France
| | | | - Alain Pélisson
- Institute of Human Genetics, UMR9002, CNRS and Université de Montpellier, Montpellier, France
| | - Anna-Sophie Fiston-Lavier
- ISEM, Université Montpellier, CNRS, IRD, CIRAD, EPHE, Montpellier, France
- Institut Universitaire de France (IUF), Paris, France
| | - Séverine Chambeyron
- Institute of Human Genetics, UMR9002, CNRS and Université de Montpellier, Montpellier, France
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10
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Moresi NG, Geck RC, Skophammer R, Godin D, Students YE, Taylor MB, Dunham MJ. Caffeine-tolerant mutations selected through an at-home yeast experimental evolution teaching lab. MICROPUBLICATION BIOLOGY 2023; 2023:10.17912/micropub.biology.000749. [PMID: 36855741 PMCID: PMC9968401 DOI: 10.17912/micropub.biology.000749] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Figures] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 02/02/2023] [Accepted: 01/01/1970] [Indexed: 03/02/2023]
Abstract
yEvo is a curriculum for high school students centered around evolution experiments in S. cerevisiae . To adapt the curriculum for remote instruction, we created a new protocol to evolve non-engineered yeast in the presence of caffeine. Evolved strains had increased caffeine tolerance and distinct colony morphologies. Many possessed copy number variations, transposon insertions, and mutations affecting genes with known relationships to caffeine and TOR signaling - which is inhibited by caffeine - and in other genes not previously connected with caffeine. This demonstrates that our accessible, at-home protocol is sufficient to permit novel insights into caffeine tolerance.
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Affiliation(s)
- Naomi G Moresi
- Genome Sciences, University of Washington, Seattle, Washington, United States
| | - Renee C Geck
- Genome Sciences, University of Washington, Seattle, Washington, United States
| | | | - Dennis Godin
- Genome Sciences, University of Washington, Seattle, Washington, United States
| | - yEvo Students
- Westridge School, Pasadena, California, United States
| | - M Bryce Taylor
- Program in Biology, Loras College, Dubuque, Iowa, United States
| | - Maitreya J Dunham
- Genome Sciences, University of Washington, Seattle, Washington, United States
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11
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Moresi NG, Geck RC, Skophammer R, Godin D, Taylor MB, Dunham MJ. Caffeine-tolerant mutations selected through an at-home yeast experimental evolution teaching lab. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.17.524437. [PMID: 36712001 PMCID: PMC9882195 DOI: 10.1101/2023.01.17.524437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
yEvo is a curriculum for high school students centered around evolution experiments in S. cerevisiae . To adapt the curriculum for remote instruction, we created a new protocol to evolve non-GMO yeast in the presence of caffeine. Evolved strains had increased caffeine tolerance and distinct colony morphologies. Many possessed copy number variations, transposon insertions, and mutations affecting genes with known relationships to caffeine and TOR signaling - which is inhibited by caffeine - and in other genes not previously connected with caffeine. This demonstrates that our accessible, at-home protocol is sufficient to permit novel insights into caffeine tolerance.
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Affiliation(s)
- Naomi G. Moresi
- Department of Genome Sciences, University of Washington, Seattle, WA 98195
| | - Renee C. Geck
- Department of Genome Sciences, University of Washington, Seattle, WA 98195
| | | | - Dennis Godin
- Department of Genome Sciences, University of Washington, Seattle, WA 98195
| | | | | | - Maitreya J. Dunham
- Department of Genome Sciences, University of Washington, Seattle, WA 98195
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12
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Abstract
The detection and quantification of transposable elements (TE) are notoriously challenging despite their relevance in evolutionary genomics and molecular ecology. The main hurdle is caused by the dependence of numerous tools on genome assemblies, whose level of completion directly affects the comparability of the results across species or populations. dnaPipeTE, whose use is demonstrated here, tackles this issue by directly performing TE detection, classification, and quantification from unassembled short reads. This chapter details all the required steps to perform a comparative analysis of the TE content between two related species, starting from the installation of a recently containerized version of the program to the post-processing of the outputs.
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Affiliation(s)
- Clément Goubert
- Canadian Centre for Computational Genomics, McGill University, Montreal, QC, Canada.
- McGill Genome Centre, Montreal, QC, Canada.
- Human Genetics, McGill University, Montreal, QC, Canada.
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13
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Hiltunen M, Ament-Velásquez SL, Ryberg M, Johannesson H. Stage-specific transposon activity in the life cycle of the fairy-ring mushroom Marasmius oreades. Proc Natl Acad Sci U S A 2022; 119:e2208575119. [PMID: 36343254 PMCID: PMC9674265 DOI: 10.1073/pnas.2208575119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 10/02/2022] [Indexed: 11/09/2022] Open
Abstract
Genetic variability can be generated by different mechanisms, and across the life cycle. Many basidiomycete fungi have an extended somatic stage, during which each cell carries two genetically distinct haploid nuclei (dikaryosis), resulting from fusion of two compatible monokaryotic individuals. Recent findings have revealed remarkable genome stability at the nucleotide level during dikaryotic growth in these organisms, but whether this pattern extends to mutations affecting large genomic regions remains unknown. Furthermore, despite high genome integrity during dikaryosis, basidiomycete populations are not devoid of genetic diversity, begging the question of when this diversity is introduced. Here, we used a Marasmius oreades fairy ring to investigate the rise of large-scale variants during mono- and dikaryosis. By separating the two nuclear genotypes from four fruiting bodies and generating complete genome assemblies, we gained access to investigate genomic changes of any size. We found that during dikaryotic growth in nature the genome stayed intact, but after separating the nucleotypes into monokaryons, a considerable amount of structural variation started to accumulate, driven to large extent by transposons. Transposon insertions were also found in monokaryotic single-meiospore isolates. Hence, we show that genome integrity in basidiomycetes can be interrupted during monokaryosis, leading to genomic rearrangements and increased activity of transposable elements. We suggest that genetic diversification is disproportionate between life cycle stages in mushroom-forming fungi, so that the short-lived monokaryotic growth stage is more prone to genetic changes than the dikaryotic stage.
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Affiliation(s)
- Markus Hiltunen
- Department of Organismal Biology, Uppsala University, SE-752 36 Uppsala, Sweden
| | | | - Martin Ryberg
- Department of Organismal Biology, Uppsala University, SE-752 36 Uppsala, Sweden
| | - Hanna Johannesson
- Department of Organismal Biology, Uppsala University, SE-752 36 Uppsala, Sweden
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14
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Taylor MB, Skophammer R, Warwick AR, Geck RC, Boyer JM, Walson M, Large CRL, Hickey ASM, Rowley PA, Dunham MJ. yEvo: experimental evolution in high school classrooms selects for novel mutations that impact clotrimazole resistance in Saccharomyces cerevisiae. G3 (BETHESDA, MD.) 2022; 12:jkac246. [PMID: 36173330 PMCID: PMC9635649 DOI: 10.1093/g3journal/jkac246] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 08/15/2022] [Indexed: 11/18/2022]
Abstract
Antifungal resistance in pathogenic fungi is a growing global health concern. Nonpathogenic laboratory strains of Saccharomyces cerevisiae are an important model for studying mechanisms of antifungal resistance that are relevant to understanding the same processes in pathogenic fungi. We have developed a series of laboratory modules in which high school students used experimental evolution to study antifungal resistance by isolating azole-resistant S. cerevisiae mutants and examining the genetic basis of resistance. We have sequenced 99 clones from these experiments and found that all possessed mutations previously shown to impact azole resistance, validating our approach. We additionally found recurrent mutations in an mRNA degradation pathway and an uncharacterized mitochondrial protein (Csf1) that have possible mechanistic connections to azole resistance. The scale of replication in this initiative allowed us to identify candidate epistatic interactions, as evidenced by pairs of mutations that occur in the same clone more frequently than expected by chance (positive epistasis) or less frequently (negative epistasis). We validated one of these pairs, a negative epistatic interaction between gain-of-function mutations in the multidrug resistance transcription factors Pdr1 and Pdr3. This high school-university collaboration can serve as a model for involving members of the broader public in the scientific process to make meaningful discoveries in biomedical research.
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Affiliation(s)
- Matthew Bryce Taylor
- Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA
- Program in Biology, Loras College, Dubuque, IA 52001, USA
| | | | - Alexa R Warwick
- Department of Fisheries and Wildlife, Michigan State University, East Lansing, MI 48824, USA
| | - Renee C Geck
- Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA
| | - Josephine M Boyer
- Department of Biological Sciences, University of Idaho, Moscow, ID 83844, USA
| | - yEvo Students
- Westridge School, Pasadena, CA 91105, USA
- Moscow High School, Moscow, ID 83843, USA
| | - Margaux Walson
- Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA
| | - Christopher R L Large
- Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA
- UW Molecular and Cellular Biology Program, University of Washington, Seattle, WA 98195, USA
| | - Angela Shang-Mei Hickey
- Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA
- Present address: Department of Genetics, Stanford University, Biomedical Innovations Building, Palo Alto, CA 94304, USA
| | - Paul A Rowley
- Department of Biological Sciences, University of Idaho, Moscow, ID 83844, USA
| | - Maitreya J Dunham
- Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA
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15
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Ecovoiu AA, Bologa AM, Chifiriuc DIM, Ciuca AM, Constantin ND, Ghionoiu IC, Ghita IC, Ratiu AC. Genome ARTIST_v2-An Autonomous Bioinformatics Tool for Annotation of Natural Transposons in Sequenced Genomes. Int J Mol Sci 2022; 23:ijms232012686. [PMID: 36293549 PMCID: PMC9604107 DOI: 10.3390/ijms232012686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 10/15/2022] [Accepted: 10/18/2022] [Indexed: 11/05/2022] Open
Abstract
The annotation of transposable elements (transposons) is a very dynamic field of genomics and various tools assigned to support this bioinformatics endeavor have been developed and described. Genome ARTIST v1.19 (GA_v1.19) software was conceived for mapping artificial transposons mobilized during insertional mutagenesis projects, but the new functions of GA_v2 qualify it as a tool for the mapping and annotation of natural transposons (NTs) in long reads, contigs and assembled genomes. The tabular export of mapping and annotation data for high-throughput data analysis, the generation of a list of flanking sequences around the coordinates of insertion or around the target site duplications and the computing of a consensus sequence for the flanking sequences are all key assets of GA_v2. Additionally, we developed a set of scripts that enable the user to annotate NTs, to harness annotations offered by FlyBase for Drosophila melanogaster genome, to convert sequence files from .fasta to .raw, and to extract junction query sequences essential for NTs mapping. Herein, we present the applicability of GA_v2 for a preliminary annotation of P-element and hobo class II NTs and copia retrotransposon in the genome of D. melanogaster strain Horezu_LaPeri (Horezu), Romania, which was sequenced with Nanopore technology in our laboratory. We used contigs assembled with Flye tool and a Q10 quality filter of the reads. Our results suggest that GA_v2 is a reliable autonomous tool able to perform mapping and annotation of NTs in genomes sequenced by long sequencing technology. GA_v2 is open-source software compatible with Linux, Mac OS and Windows and is available at GitHub repository and dedicated website.
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Affiliation(s)
- Alexandru Al. Ecovoiu
- Department of Genetics, Faculty of Biology, University of Bucharest, 060101 Bucharest, Romania
- Correspondence: (A.A.E.); (A.C.R.); Tel.: +40-725564416 (A.A.E.); +40-722250366 (A.C.R.)
| | - Alexandru Marian Bologa
- Department of Genetics, Faculty of Biology, University of Bucharest, 060101 Bucharest, Romania
| | | | | | | | | | - Iulian Cristian Ghita
- Department of Genetics, Faculty of Biology, University of Bucharest, 060101 Bucharest, Romania
| | - Attila Cristian Ratiu
- Department of Genetics, Faculty of Biology, University of Bucharest, 060101 Bucharest, Romania
- Correspondence: (A.A.E.); (A.C.R.); Tel.: +40-725564416 (A.A.E.); +40-722250366 (A.C.R.)
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16
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Scarlett VT, Lovell JT, Shao M, Phillips J, Shu S, Lusinska J, Goodstein DM, Jenkins J, Grimwood J, Barry K, Chalhoub B, Schmutz J, Hasterok R, Catalán P, Vogel JP. Multiple origins, one evolutionary trajectory: gradual evolution characterizes distinct lineages of allotetraploid Brachypodium. Genetics 2022; 223:6758249. [PMID: 36218464 PMCID: PMC9910409 DOI: 10.1093/genetics/iyac146] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 09/16/2022] [Indexed: 11/13/2022] Open
Abstract
The "genomic shock" hypothesis posits that unusual challenges to genome integrity such as whole genome duplication may induce chaotic genome restructuring. Decades of research on polyploid genomes have revealed that this is often, but not always the case. While some polyploids show major chromosomal rearrangements and derepression of transposable elements in the immediate aftermath of whole genome duplication, others do not. Nonetheless, all polyploids show gradual diploidization over evolutionary time. To evaluate these hypotheses, we produced a chromosome-scale reference genome for the natural allotetraploid grass Brachypodium hybridum, accession "Bhyb26." We compared 2 independently derived accessions of B. hybridum and their deeply diverged diploid progenitor species Brachypodium stacei and Brachypodium distachyon. The 2 B. hybridum lineages provide a natural timecourse in genome evolution because one formed 1.4 million years ago, and the other formed 140 thousand years ago. The genome of the older lineage reveals signs of gradual post-whole genome duplication genome evolution including minor gene loss and genome rearrangement that are missing from the younger lineage. In neither B. hybridum lineage do we find signs of homeologous recombination or pronounced transposable element activation, though we find evidence supporting steady post-whole genome duplication transposable element activity in the older lineage. Gene loss in the older lineage was slightly biased toward 1 subgenome, but genome dominance was not observed at the transcriptomic level. We propose that relaxed selection, rather than an abrupt genomic shock, drives evolutionary novelty in B. hybridum, and that the progenitor species' similarity in transposable element load may account for the subtlety of the observed genome dominance.
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Affiliation(s)
- Virginia T Scarlett
- U.S. Dept. of Energy Joint Genome Institute, Berkeley, CA 94720, USA,Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - John T Lovell
- Genome Sequencing Center, HudsonAlpha Institute for Biotechnology, Huntsville, AL 35806, USA
| | - Mingqin Shao
- U.S. Dept. of Energy Joint Genome Institute, Berkeley, CA 94720, USA
| | - Jeremy Phillips
- U.S. Dept. of Energy Joint Genome Institute, Berkeley, CA 94720, USA
| | - Shengqiang Shu
- U.S. Dept. of Energy Joint Genome Institute, Berkeley, CA 94720, USA
| | | | - David M Goodstein
- U.S. Dept. of Energy Joint Genome Institute, Berkeley, CA 94720, USA
| | - Jerry Jenkins
- Genome Sequencing Center, HudsonAlpha Institute for Biotechnology, Huntsville, AL 35806, USA
| | - Jane Grimwood
- Genome Sequencing Center, HudsonAlpha Institute for Biotechnology, Huntsville, AL 35806, USA
| | - Kerrie Barry
- U.S. Dept. of Energy Joint Genome Institute, Berkeley, CA 94720, USA
| | | | - Jeremy Schmutz
- U.S. Dept. of Energy Joint Genome Institute, Berkeley, CA 94720, USA,Genome Sequencing Center, HudsonAlpha Institute for Biotechnology, Huntsville, AL 35806, USA
| | | | | | - John P Vogel
- Corresponding author: U.S. Dept. of Energy Joint Genome Institute, 1 Cyclotron Road, Berkeley, CA 94720, USA.
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17
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Han S, Dias GB, Basting PJ, Viswanatha R, Perrimon N, Bergman C. Local assembly of long reads enables phylogenomics of transposable elements in a polyploid cell line. Nucleic Acids Res 2022; 50:e124. [PMID: 36156149 PMCID: PMC9757076 DOI: 10.1093/nar/gkac794] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 07/21/2022] [Accepted: 09/16/2022] [Indexed: 12/24/2022] Open
Abstract
Animal cell lines often undergo extreme genome restructuring events, including polyploidy and segmental aneuploidy that can impede de novo whole-genome assembly (WGA). In some species like Drosophila, cell lines also exhibit massive proliferation of transposable elements (TEs). To better understand the role of transposition during animal cell culture, we sequenced the genome of the tetraploid Drosophila S2R+ cell line using long-read and linked-read technologies. WGAs for S2R+ were highly fragmented and generated variable estimates of TE content across sequencing and assembly technologies. We therefore developed a novel WGA-independent bioinformatics method called TELR that identifies, locally assembles, and estimates allele frequency of TEs from long-read sequence data (https://github.com/bergmanlab/telr). Application of TELR to a ∼130x PacBio dataset for S2R+ revealed many haplotype-specific TE insertions that arose by transposition after initial cell line establishment and subsequent tetraploidization. Local assemblies from TELR also allowed phylogenetic analysis of paralogous TEs, which revealed that proliferation of TE families in vitro can be driven by single or multiple source lineages. Our work provides a model for the analysis of TEs in complex heterozygous or polyploid genomes that are recalcitrant to WGA and yields new insights into the mechanisms of genome evolution in animal cell culture.
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Affiliation(s)
| | | | - Preston J Basting
- Institute of Bioinformatics, University of Georgia, 120 E. Green St., Athens, GA, USA
| | - Raghuvir Viswanatha
- Department of Genetics, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA, USA
| | - Norbert Perrimon
- Department of Genetics, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA, USA,Howard Hughes Medical Institute, Boston, MA, USA
| | - Casey M Bergman
- To whom correspondence should be addressed. Tel: +1 706 542 1764; Fax: +1 706 542 3910;
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18
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Samoluk SS, Vaio M, Ortíz AM, Chalup LMI, Robledo G, Bertioli DJ, Seijo G. Comparative repeatome analysis reveals new evidence on genome evolution in wild diploid Arachis (Fabaceae) species. PLANTA 2022; 256:50. [PMID: 35895167 DOI: 10.1007/s00425-022-03961-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 07/12/2022] [Indexed: 06/15/2023]
Abstract
Opposing changes in the abundance of satellite DNA and long terminal repeat (LTR) retroelements are the main contributors to the variation in genome size and heterochromatin amount in Arachis diploids. The South American genus Arachis (Fabaceae) comprises 83 species organized in nine taxonomic sections. Among them, section Arachis is characterized by species with a wide genome and karyotype diversity. Such diversity is determined mainly by the amount and composition of repetitive DNA. Here we performed computational analysis on low coverage genome sequencing to infer the dynamics of changes in major repeat families that led to the differentiation of genomes in diploid species (x = 10) of genus Arachis, focusing on section Arachis. Estimated repeat content ranged from 62.50 to 71.68% of the genomes. Species with different genome composition tended to have different landscapes of repeated sequences. Athila family retrotransposons were the most abundant and variable lineage among Arachis repeatomes, with peaks of transpositional activity inferred at different times in the evolution of the species. Satellite DNAs (satDNAs) were less abundant, but differentially represented among species. High rates of evolution of an AT-rich superfamily of satDNAs led to the differential accumulation of heterochromatin in Arachis genomes. The relationship between genome size variation and the repetitive content is complex. However, largest genomes presented a higher accumulation of LTR elements and lower contents of satDNAs. In contrast, species with lowest genome sizes tended to accumulate satDNAs in detriment of LTR elements. Phylogenetic analysis based on repetitive DNA supported the genome arrangement of section Arachis. Altogether, our results provide the most comprehensive picture on the repeatome dynamics that led to the genome differentiation of Arachis species.
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Affiliation(s)
- Sergio S Samoluk
- Instituto de Botánica del Nordeste (UNNE-CONICET), Facultad de Ciencias Agrarias, Corrientes, Argentina.
| | - Magdalena Vaio
- Laboratory of Plant Genome Evolution and Domestication, Department of Plant Biology, Faculty of Agronomy, University of the Republic, Montevideo, Uruguay
| | - Alejandra M Ortíz
- Instituto de Botánica del Nordeste (UNNE-CONICET), Facultad de Ciencias Agrarias, Corrientes, Argentina
| | - Laura M I Chalup
- Instituto de Botánica del Nordeste (UNNE-CONICET), Facultad de Ciencias Agrarias, Corrientes, Argentina
| | - Germán Robledo
- Instituto de Botánica del Nordeste (UNNE-CONICET), Facultad de Ciencias Agrarias, Corrientes, Argentina
- Facultad de Ciencias Exactas y Naturales y Agrimensura, Universidad Nacional del Nordeste, Corrientes, Argentina
| | - David J Bertioli
- Center for Applied Genetic Technologies, University of Georgia, Athens, GA, USA
| | - Guillermo Seijo
- Instituto de Botánica del Nordeste (UNNE-CONICET), Facultad de Ciencias Agrarias, Corrientes, Argentina
- Facultad de Ciencias Exactas y Naturales y Agrimensura, Universidad Nacional del Nordeste, Corrientes, Argentina
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19
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Han S, Dias GB, Basting PJ, Nelson MG, Patel S, Marzo M, Bergman CM. Ongoing transposition in cell culture reveals the phylogeny of diverse Drosophila S2 sublines. Genetics 2022; 221:iyac077. [PMID: 35536183 PMCID: PMC9252272 DOI: 10.1093/genetics/iyac077] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 04/28/2022] [Indexed: 11/13/2022] Open
Abstract
Cultured cells are widely used in molecular biology despite poor understanding of how cell line genomes change in vitro over time. Previous work has shown that Drosophila cultured cells have a higher transposable element content than whole flies, but whether this increase in transposable element content resulted from an initial burst of transposition during cell line establishment or ongoing transposition in cell culture remains unclear. Here, we sequenced the genomes of 25 sublines of Drosophila S2 cells and show that transposable element insertions provide abundant markers for the phylogenetic reconstruction of diverse sublines in a model animal cell culture system. DNA copy number evolution across S2 sublines revealed dramatically different patterns of genome organization that support the overall evolutionary history reconstructed using transposable element insertions. Analysis of transposable element insertion site occupancy and ancestral states support a model of ongoing transposition dominated by episodic activity of a small number of retrotransposon families. Our work demonstrates that substantial genome evolution occurs during long-term Drosophila cell culture, which may impact the reproducibility of experiments that do not control for subline identity.
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Affiliation(s)
- Shunhua Han
- Institute of Bioinformatics, University of Georgia, Athens, GA 30602, USA
| | - Guilherme B Dias
- Institute of Bioinformatics, University of Georgia, Athens, GA 30602, USA
- Department of Genetics, University of Georgia, Athens, GA 30602, USA
| | - Preston J Basting
- Institute of Bioinformatics, University of Georgia, Athens, GA 30602, USA
| | - Michael G Nelson
- Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, UK
| | - Sanjai Patel
- Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, UK
| | - Mar Marzo
- Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, UK
| | - Casey M Bergman
- Institute of Bioinformatics, University of Georgia, Athens, GA 30602, USA
- Department of Genetics, University of Georgia, Athens, GA 30602, USA
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20
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Serra O, de Sousa RM, Guimarães JB, Matos J, Vicente P, de Sousa ML, Simões F. Genome-wide clonal variability in European pear "Rocha" using high-throughput sequencing. HORTICULTURE RESEARCH 2022; 9:uhac111. [PMID: 38486834 PMCID: PMC10939347 DOI: 10.1093/hr/uhac111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 04/27/2022] [Indexed: 03/17/2024]
Abstract
Pears (Pyrus) are one of the most economically important fruits worldwide. The Pyrus genus is characterized by a high degree of genetic variability between species and interspecific hybrids, and several studies have been performed to assess this variability for both cultivated and wild accessions. These studies have mostly been limited by the resolving power of traditional molecular markers, although in the recent past the availability of reference genome sequences or SNP arrays for pear have enhanced the capability of high-resolution genomics studies. These tools can also be applied to better understand the intra-varietal (or clonal) variability in pear. Here we report the first high resolution genomics analysis of a pear clonal population using whole genome sequencing (WGS). Results showed unique signatures for the accumulation of mutations and transposable element insertions in each clone, which are likely related to their history of propagation and cultivation. The nucleotide diversity remained low in the clonal collection with the exception of few genomic windows, suggesting that balancing selection may be occurring. These windows included mainly genes related to plant fertility. Regions with higher mutational load were partially associated with transcription factors, probably reflecting the distinctive phenotypes in the collection. The annotation of variants also revealed the theoretical disruption of relevant genes in pear. Taken together, the results from this study show that pear clones accumulate mutations differently, and that those mutations can play a role on pear phenotypes, meaning that the study of pear clonal populations can be relevant in genetic studies, mainly when comparing with traditional association studies.
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Affiliation(s)
- Octávio Serra
- Instituto Nacional de Investigação Agrária e Veterinária, I.P., Banco Português de Germoplasma Vegetal (BPGV), Quinta de S. José, S. Pedro de Merelim 4700-859 Braga, Portugal
| | - Rui Maia de Sousa
- Instituto Nacional de Investigação Agrária e Veterinária, I.P., Estação Nacional de Fruticultura Vieira Natividade (ENFVN), Estrada de Leiria 2460-059 Alcobaça, Portugal
| | - Joana Bagoin Guimarães
- Instituto Nacional de Investigação Agrária e Veterinária, I.P., Quinta do Marquês, 2780-159 Oeiras, Portugal
| | - José Matos
- Instituto Nacional de Investigação Agrária e Veterinária, I.P., Quinta do Marquês, 2780-159 Oeiras, Portugal
- Centre for Ecology, Evolution and Environmental Changes, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal
| | - Patricia Vicente
- Instituto Nacional de Investigação Agrária e Veterinária, I.P., Estação Nacional de Fruticultura Vieira Natividade (ENFVN), Estrada de Leiria 2460-059 Alcobaça, Portugal
| | - Miguel Leão de Sousa
- Instituto Nacional de Investigação Agrária e Veterinária, I.P., Estação Nacional de Fruticultura Vieira Natividade (ENFVN), Estrada de Leiria 2460-059 Alcobaça, Portugal
| | - Fernanda Simões
- Instituto Nacional de Investigação Agrária e Veterinária, I.P., Quinta do Marquês, 2780-159 Oeiras, Portugal
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21
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Yan H, Haak DC, Li S, Huang L, Bombarely A. Exploring transposable element-based markers to identify allelic variations underlying agronomic traits in rice. PLANT COMMUNICATIONS 2022; 3:100270. [PMID: 35576152 PMCID: PMC9251385 DOI: 10.1016/j.xplc.2021.100270] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 10/29/2021] [Accepted: 12/16/2021] [Indexed: 06/10/2023]
Abstract
Transposable elements (TEs) are a major force in the production of new alleles during domestication; nevertheless, their use in association studies has been limited because of their complexity. We have developed a TE genotyping pipeline (TEmarker) and applied it to whole-genome genome-wide association study (GWAS) data from 176 Oryza sativa subsp. japonica accessions to identify genetic elements associated with specific agronomic traits. TE markers recovered a large proportion (69%) of single-nucleotide polymorphism (SNP)-based GWAS peaks, and these TE peaks retained ca. 25% of the SNPs. The use of TEs in GWASs may reduce false positives associated with linkage disequilibrium (LD) among SNP markers. A genome scan revealed positive selection on TEs associated with agronomic traits. We found several cases of insertion and deletion variants that potentially resulted from the direct action of TEs, including an allele of LOC_Os11g08410 associated with plant height and panicle length traits. Together, these findings reveal the utility of TE markers for connecting genotype to phenotype and suggest a potential role for TEs in influencing phenotypic variations in rice that impact agronomic traits.
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Affiliation(s)
- Haidong Yan
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, VA 24061, USA
| | - David C Haak
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, VA 24061, USA; Graduate Program in Genetics, Bioinformatics and Computational Biology (GBCB), Virginia Tech, Blacksburg, VA 24061, USA
| | - Song Li
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, VA 24061, USA; Graduate Program in Genetics, Bioinformatics and Computational Biology (GBCB), Virginia Tech, Blacksburg, VA 24061, USA
| | - Linkai Huang
- Department of Grassland Science, Animal Science and Technology College, Sichuan Agricultural University, Chengdu 611130, China
| | - Aureliano Bombarely
- Department of Bioscience, Universita degli Studi di Milano (UNIMI), 20133 Milano, Italy; Instituto de Biologıa Molecular y Celular de Plantas (IBMCP), UPV-CSIC, 46022 Valencia, Spain.
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22
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Navarro-Dominguez B, Chang CH, Brand CL, Muirhead CA, Presgraves DC, Larracuente AM. Epistatic selection on a selfish Segregation Distorter supergene - drive, recombination, and genetic load. eLife 2022; 11:e78981. [PMID: 35486424 PMCID: PMC9122502 DOI: 10.7554/elife.78981] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2022] [Accepted: 04/20/2022] [Indexed: 11/13/2022] Open
Abstract
Meiotic drive supergenes are complexes of alleles at linked loci that together subvert Mendelian segregation resulting in preferential transmission. In males, the most common mechanism of drive involves the disruption of sperm bearing one of a pair of alternative alleles. While at least two loci are important for male drive-the driver and the target-linked modifiers can enhance drive, creating selection pressure to suppress recombination. In this work, we investigate the evolution and genomic consequences of an autosomal, multilocus, male meiotic drive system, Segregation Distorter (SD) in the fruit fly, Drosophila melanogaster. In African populations, the predominant SD chromosome variant, SD-Mal, is characterized by two overlapping, paracentric inversions on chromosome arm 2R and nearly perfect (~100%) transmission. We study the SD-Mal system in detail, exploring its components, chromosomal structure, and evolutionary history. Our findings reveal a recent chromosome-scale selective sweep mediated by strong epistatic selection for haplotypes carrying Sd, the main driving allele, and one or more factors within the double inversion. While most SD-Mal chromosomes are homozygous lethal, SD-Mal haplotypes can recombine with other, complementing haplotypes via crossing over, and with wildtype chromosomes via gene conversion. SD-Mal chromosomes have nevertheless accumulated lethal mutations, excess non-synonymous mutations, and excess transposable element insertions. Therefore, SD-Mal haplotypes evolve as a small, semi-isolated subpopulation with a history of strong selection. These results may explain the evolutionary turnover of SD haplotypes in different populations around the world and have implications for supergene evolution broadly.
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Affiliation(s)
| | - Ching-Ho Chang
- Department of Biology, University of RochesterRochesterUnited States
| | - Cara L Brand
- Department of Biology, University of RochesterRochesterUnited States
| | - Christina A Muirhead
- Department of Biology, University of RochesterRochesterUnited States
- Ronin InstituteMontclairUnited States
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23
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Finding and Characterizing Repeats in Plant Genomes. METHODS IN MOLECULAR BIOLOGY (CLIFTON, N.J.) 2022; 2443:327-385. [PMID: 35037215 DOI: 10.1007/978-1-0716-2067-0_18] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Plant genomes contain a particularly high proportion of repeated structures of various types. This chapter proposes a guided tour of the available software that can help biologists to scan automatically for these repeats in sequence data or check hypothetical models intended to characterize their structures. Since transposable elements (TEs) are a major source of repeats in plants, many methods have been used or developed for this broad class of sequences. They are representative of the range of tools available for other classes of repeats and we have provided two sections on this topic (for the analysis of genomes or directly of sequenced reads), as well as a selection of the main existing software. It may be hard to keep up with the profusion of proposals in this dynamic field and the rest of the chapter is devoted to the foundations of an efficient search for repeats and more complex patterns. We first introduce the key concepts of the art of indexing and mapping or querying sequences. We end the chapter with the more prospective issue of building models of repeat families. We present the Machine Learning approach first, seeking to build predictors automatically for some families of ET, from a set of sequences known to belong to this family. A second approach, the linguistic (or syntactic) approach, allows biologists to describe themselves and check the validity of models of their favorite repeat family.
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24
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Han S, Basting PJ, Dias GB, Luhur A, Zelhof AC, Bergman CM. Transposable element profiles reveal cell line identity and loss of heterozygosity in Drosophila cell culture. Genetics 2021; 219:6321957. [PMID: 34849875 PMCID: PMC8633141 DOI: 10.1093/genetics/iyab113] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2021] [Accepted: 07/01/2021] [Indexed: 11/28/2022] Open
Abstract
Cell culture systems allow key insights into biological mechanisms yet suffer from irreproducible outcomes in part because of cross-contamination or mislabeling of cell lines. Cell line misidentification can be mitigated by the use of genotyping protocols, which have been developed for human cell lines but are lacking for many important model species. Here, we leverage the classical observation that transposable elements (TEs) proliferate in cultured Drosophila cells to demonstrate that genome-wide TE insertion profiles can reveal the identity and provenance of Drosophila cell lines. We identify multiple cases where TE profiles clarify the origin of Drosophila cell lines (Sg4, mbn2, and OSS_E) relative to published reports, and also provide evidence that insertions from only a subset of long-terminal repeat retrotransposon families are necessary to mark Drosophila cell line identity. We also develop a new bioinformatics approach to detect TE insertions and estimate intra-sample allele frequencies in legacy whole-genome sequencing data (called ngs_te_mapper2), which revealed loss of heterozygosity as a mechanism shaping the unique TE profiles that identify Drosophila cell lines. Our work contributes to the general understanding of the forces impacting metazoan genomes as they evolve in cell culture and paves the way for high-throughput protocols that use TE insertions to authenticate cell lines in Drosophila and other organisms.
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Affiliation(s)
- Shunhua Han
- Department of Genetics and Institute of Bioinformatics, University of Georgia, Athens, GA 30602, USA
| | - Preston J Basting
- Department of Genetics and Institute of Bioinformatics, University of Georgia, Athens, GA 30602, USA
| | - Guilherme B Dias
- Department of Genetics and Institute of Bioinformatics, University of Georgia, Athens, GA 30602, USA.,Department of Genetics, University of Georgia, Athens, GA 30602, USA
| | - Arthur Luhur
- Drosophila Genomics Resource Center, Indiana University, Bloomington, IN 47405, USA.,Department of Biology, Indiana University, Bloomington, IN 47405, USA
| | - Andrew C Zelhof
- Drosophila Genomics Resource Center, Indiana University, Bloomington, IN 47405, USA.,Department of Biology, Indiana University, Bloomington, IN 47405, USA
| | - Casey M Bergman
- Department of Genetics and Institute of Bioinformatics, University of Georgia, Athens, GA 30602, USA.,Department of Genetics, University of Georgia, Athens, GA 30602, USA
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25
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Oggenfuss U, Badet T, Wicker T, Hartmann FE, Singh NK, Abraham L, Karisto P, Vonlanthen T, Mundt C, McDonald BA, Croll D. A population-level invasion by transposable elements triggers genome expansion in a fungal pathogen. eLife 2021; 10:e69249. [PMID: 34528512 PMCID: PMC8445621 DOI: 10.7554/elife.69249] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Accepted: 08/28/2021] [Indexed: 12/16/2022] Open
Abstract
Genome evolution is driven by the activity of transposable elements (TEs). The spread of TEs can have deleterious effects including the destabilization of genome integrity and expansions. However, the precise triggers of genome expansions remain poorly understood because genome size evolution is typically investigated only among deeply divergent lineages. Here, we use a large population genomics dataset of 284 individuals from populations across the globe of Zymoseptoria tritici, a major fungal wheat pathogen. We built a robust map of genome-wide TE insertions and deletions to track a total of 2456 polymorphic loci within the species. We show that purifying selection substantially depressed TE frequencies in most populations, but some rare TEs have recently risen in frequency and likely confer benefits. We found that specific TE families have undergone a substantial genome-wide expansion from the pathogen's center of origin to more recently founded populations. The most dramatic increase in TE insertions occurred between a pair of North American populations collected in the same field at an interval of 25 years. We find that both genome-wide counts of TE insertions and genome size have increased with colonization bottlenecks. Hence, the demographic history likely played a major role in shaping genome evolution within the species. We show that both the activation of specific TEs and relaxed purifying selection underpin this incipient expansion of the genome. Our study establishes a model to recapitulate TE-driven genome evolution over deeper evolutionary timescales.
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Affiliation(s)
- Ursula Oggenfuss
- Laboratory of Evolutionary Genetics, Institute of Biology, University of NeuchâtelNeuchatelSwitzerland
| | - Thomas Badet
- Laboratory of Evolutionary Genetics, Institute of Biology, University of NeuchâtelNeuchatelSwitzerland
| | - Thomas Wicker
- Institute for Plant and Microbial Biology, University of ZurichZurichSwitzerland
| | - Fanny E Hartmann
- Ecologie Systématique Evolution, Bâtiment 360, Univ. Paris-Sud, AgroParisTech, CNRS, Université Paris-SaclayOrsayFrance
- Plant Pathology, Institute of Integrative Biology, ETH ZurichZurichSwitzerland
| | - Nikhil Kumar Singh
- Laboratory of Evolutionary Genetics, Institute of Biology, University of NeuchâtelNeuchatelSwitzerland
| | - Leen Abraham
- Laboratory of Evolutionary Genetics, Institute of Biology, University of NeuchâtelNeuchatelSwitzerland
| | - Petteri Karisto
- Plant Pathology, Institute of Integrative Biology, ETH ZurichZurichSwitzerland
| | - Tiziana Vonlanthen
- Plant Pathology, Institute of Integrative Biology, ETH ZurichZurichSwitzerland
| | - Christopher Mundt
- Department of Botany and Plant Pathology, Oregon State UniversityCorvallisUnited States
| | - Bruce A McDonald
- Plant Pathology, Institute of Integrative Biology, ETH ZurichZurichSwitzerland
| | - Daniel Croll
- Laboratory of Evolutionary Genetics, Institute of Biology, University of NeuchâtelNeuchatelSwitzerland
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26
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Negm S, Greenberg A, Larracuente A, Sproul J. RepeatProfiler: A pipeline for visualization and comparative analysis of repetitive DNA profiles. Mol Ecol Resour 2021; 21:969-981. [PMID: 33277787 PMCID: PMC7954937 DOI: 10.1111/1755-0998.13305] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 11/11/2020] [Accepted: 11/30/2020] [Indexed: 12/20/2022]
Abstract
Study of repetitive DNA elements in model organisms highlights the role of repetitive elements (REs) in many processes that drive genome evolution and phenotypic change. Because REs are much more dynamic than single-copy DNA, repetitive sequences can reveal signals of evolutionary history over short time scales that may not be evident in sequences from slower-evolving genomic regions. Many tools for studying REs are directed toward organisms with existing genomic resources, including genome assemblies and repeat libraries. However, signals in repeat variation may prove especially valuable in disentangling evolutionary histories in diverse non-model groups, for which genomic resources are limited. Here, we introduce RepeatProfiler, a tool for generating, visualizing, and comparing repetitive element DNA profiles from low-coverage, short-read sequence data. RepeatProfiler automates the generation and visualization of RE coverage depth profiles (RE profiles) and allows for statistical comparison of profile shape across samples. In addition, RepeatProfiler facilitates comparison of profiles by extracting signal from sequence variants across profiles which can then be analysed as molecular morphological characters using phylogenetic analysis. We validate RepeatProfiler with data sets from ground beetles (Bembidion), flies (Drosophila), and tomatoes (Solanum). We highlight the potential of RE profiles as a high-resolution data source for studies in species delimitation, comparative genomics, and repeat biology.
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Affiliation(s)
- S. Negm
- University of Rochester, Department of Biology, 337 Hutchison Hall, Rochester, NY, 14627
| | - A. Greenberg
- University of Rochester, Department of Biology, 337 Hutchison Hall, Rochester, NY, 14627
| | - A.M. Larracuente
- University of Rochester, Department of Biology, 337 Hutchison Hall, Rochester, NY, 14627
| | - J.S. Sproul
- University of Rochester, Department of Biology, 337 Hutchison Hall, Rochester, NY, 14627
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27
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Chen P, Zhang J. Asexual Experimental Evolution of Yeast Does Not Curtail Transposable Elements. Mol Biol Evol 2021; 38:2831-2842. [PMID: 33720342 PMCID: PMC8233515 DOI: 10.1093/molbev/msab073] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Compared with asexual reproduction, sex facilitates the transmission of transposable elements (TEs) from one genome to another, but boosts the efficacy of selection against deleterious TEs. Thus, theoretically, it is unclear whether sex has a positive net effect on TE’s proliferation. An empirical study concluded that sex is at the root of TE’s evolutionary success because the yeast TE load was found to decrease rapidly in approximately 1,000 generations of asexual but not sexual experimental evolution. However, this finding contradicts the maintenance of TEs in natural yeast populations where sexual reproduction occurs extremely infrequently. Here, we show that the purported TE load reduction during asexual experimental evolution is likely an artifact of low genomic sequencing coverages. We observe stable TE loads in both sexual and asexual experimental evolution from multiple yeast data sets with sufficient coverages. To understand the evolutionary dynamics of yeast TEs, we turn to asexual mutation accumulation lines that have been under virtually no selection. We find that both TE transposition and excision rates per generation, but not their difference, tend to be higher in environments where yeast grows more slowly. However, the transposition rate is not significantly higher than the excision rate and the variance of the TE number among natural strains is close to its neutral expectation, suggesting that selection against TEs is at best weak in yeast. We conclude that the yeast TE load is maintained largely by a transposition–excision balance and that the influence of sex remains unclear.
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Affiliation(s)
- Piaopiao Chen
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, USA
| | - Jianzhi Zhang
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, USA
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28
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Fabian DK, Dönertaş HM, Fuentealba M, Partridge L, Thornton JM. Transposable Element Landscape in Drosophila Populations Selected for Longevity. Genome Biol Evol 2021; 13:6141024. [PMID: 33595657 PMCID: PMC8355499 DOI: 10.1093/gbe/evab031] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/11/2021] [Indexed: 12/11/2022] Open
Abstract
Transposable elements (TEs) inflict numerous negative effects on health and fitness as they replicate by integrating into new regions of the host genome. Even though organisms employ powerful mechanisms to demobilize TEs, transposons gradually lose repression during aging. The rising TE activity causes genomic instability and was implicated in age-dependent neurodegenerative diseases, inflammation, and the determination of lifespan. It is therefore conceivable that long-lived individuals have improved TE silencing mechanisms resulting in reduced TE expression relative to their shorter-lived counterparts and fewer genomic insertions. Here, we test this hypothesis by performing the first genome-wide analysis of TE insertions and expression in populations of Drosophila melanogaster selected for longevity through late-life reproduction for 50–170 generations from four independent studies. Contrary to our expectation, TE families were generally more abundant in long-lived populations compared with nonselected controls. Although simulations showed that this was not expected under neutrality, we found little evidence for selection driving TE abundance differences. Additional RNA-seq analysis revealed a tendency for reducing TE expression in selected populations, which might be more important for lifespan than regulating genomic insertions. We further find limited evidence of parallel selection on genes related to TE regulation and transposition. However, telomeric TEs were genomically and transcriptionally more abundant in long-lived flies, suggesting improved telomere maintenance as a promising TE-mediated mechanism for prolonging lifespan. Our results provide a novel viewpoint indicating that reproduction at old age increases the opportunity of TEs to be passed on to the next generation with little impact on longevity.
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Affiliation(s)
- Daniel K Fabian
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, United Kingdom
- Institute of Healthy Ageing, Department of Genetics, Evolution and Environment, University College London, United Kingdom
- Corresponding author: E-mail:
| | - Handan Melike Dönertaş
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, United Kingdom
| | - Matías Fuentealba
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, United Kingdom
- Institute of Healthy Ageing, Department of Genetics, Evolution and Environment, University College London, United Kingdom
| | - Linda Partridge
- Institute of Healthy Ageing, Department of Genetics, Evolution and Environment, University College London, United Kingdom
- Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - Janet M Thornton
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, United Kingdom
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29
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Smukowski Heil C, Patterson K, Hickey ASM, Alcantara E, Dunham MJ. Transposable Element Mobilization in Interspecific Yeast Hybrids. Genome Biol Evol 2021; 13:6141023. [PMID: 33595639 PMCID: PMC7952228 DOI: 10.1093/gbe/evab033] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/11/2021] [Indexed: 12/13/2022] Open
Abstract
Barbara McClintock first hypothesized that interspecific hybridization could provide a “genomic shock” that leads to the mobilization of transposable elements (TEs). This hypothesis is based on the idea that regulation of TE movement is potentially disrupted in hybrids. However, the handful of studies testing this hypothesis have yielded mixed results. Here, we set out to identify if hybridization can increase transposition rate and facilitate colonization of TEs in Saccharomyces cerevisiae × Saccharomyces uvarum interspecific yeast hybrids. Saccharomyces cerevisiae have a small number of active long terminal repeat retrotransposons (Ty elements), whereas their distant relative S. uvarum have lost the Ty elements active in S. cerevisiae. Although the regulation system of Ty elements is known in S. cerevisiae, it is unclear how Ty elements are regulated in other Saccharomyces species, and what mechanisms contributed to the loss of most classes of Ty elements in S. uvarum. Therefore, we first assessed whether TEs could insert in the S. uvarum sub-genome of a S. cerevisiae × S. uvarum hybrid. We induced transposition to occur in these hybrids and developed a sequencing technique to show that Ty elements insert readily and nonrandomly in the S. uvarum genome. We then used an in vivo reporter construct to directly measure transposition rate in hybrids, demonstrating that hybridization itself does not alter rate of mobilization. However, we surprisingly show that species-specific mitochondrial inheritance can change transposition rate by an order of magnitude. Overall, our results provide evidence that hybridization can potentially facilitate the introduction of TEs across species boundaries and alter transposition via mitochondrial transmission, but that this does not lead to unrestrained proliferation of TEs suggested by the genomic shock theory.
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Affiliation(s)
- Caiti Smukowski Heil
- Department of Genome Sciences, University of Washington, Seattle, Washington, USA
| | - Kira Patterson
- Department of Genome Sciences, University of Washington, Seattle, Washington, USA
| | | | - Erica Alcantara
- Department of Genome Sciences, University of Washington, Seattle, Washington, USA
| | - Maitreya J Dunham
- Department of Genome Sciences, University of Washington, Seattle, Washington, USA
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30
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Della Coletta R, Qiu Y, Ou S, Hufford MB, Hirsch CN. How the pan-genome is changing crop genomics and improvement. Genome Biol 2021; 22:3. [PMID: 33397434 PMCID: PMC7780660 DOI: 10.1186/s13059-020-02224-8] [Citation(s) in RCA: 101] [Impact Index Per Article: 33.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 12/07/2020] [Indexed: 01/13/2023] Open
Abstract
Crop genomics has seen dramatic advances in recent years due to improvements in sequencing technology, assembly methods, and computational resources. These advances have led to the development of new tools to facilitate crop improvement. The study of structural variation within species and the characterization of the pan-genome has revealed extensive genome content variation among individuals within a species that is paradigm shifting to crop genomics and improvement. Here, we review advances in crop genomics and how utilization of these tools is shifting in light of pan-genomes that are becoming available for many crop species.
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Affiliation(s)
- Rafael Della Coletta
- Department of Agronomy and Plant Genetics, University of Minnesota, St. Paul, MN 55108 USA
| | - Yinjie Qiu
- Department of Agronomy and Plant Genetics, University of Minnesota, St. Paul, MN 55108 USA
| | - Shujun Ou
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA 50011 USA
| | - Matthew B. Hufford
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA 50011 USA
| | - Candice N. Hirsch
- Department of Agronomy and Plant Genetics, University of Minnesota, St. Paul, MN 55108 USA
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31
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Della Coletta R, Qiu Y, Ou S, Hufford MB, Hirsch CN. How the pan-genome is changing crop genomics and improvement. Genome Biol 2021. [PMID: 33397434 DOI: 10.1186/s13059-020-02224-2228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/17/2023] Open
Abstract
Crop genomics has seen dramatic advances in recent years due to improvements in sequencing technology, assembly methods, and computational resources. These advances have led to the development of new tools to facilitate crop improvement. The study of structural variation within species and the characterization of the pan-genome has revealed extensive genome content variation among individuals within a species that is paradigm shifting to crop genomics and improvement. Here, we review advances in crop genomics and how utilization of these tools is shifting in light of pan-genomes that are becoming available for many crop species.
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Affiliation(s)
- Rafael Della Coletta
- Department of Agronomy and Plant Genetics, University of Minnesota, St. Paul, MN, 55108, USA
| | - Yinjie Qiu
- Department of Agronomy and Plant Genetics, University of Minnesota, St. Paul, MN, 55108, USA
| | - Shujun Ou
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA, 50011, USA
| | - Matthew B Hufford
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA, 50011, USA.
| | - Candice N Hirsch
- Department of Agronomy and Plant Genetics, University of Minnesota, St. Paul, MN, 55108, USA.
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32
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Transposon expression in the Drosophila brain is driven by neighboring genes and diversifies the neural transcriptome. Genome Res 2020; 30:1559-1569. [PMID: 32973040 PMCID: PMC7605248 DOI: 10.1101/gr.259200.119] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Accepted: 09/22/2020] [Indexed: 12/15/2022]
Abstract
Somatic transposon expression in neural tissue is commonly considered as a measure of mobilization and has therefore been linked to neuropathology and organismal individuality. We combined genome sequencing data with single-cell mRNA sequencing of the same inbred fly strain to map transposon expression in the Drosophila midbrain and found that transposon expression patterns are highly stereotyped. Every detected transposon is resident in at least one cellular gene with a matching expression pattern. Bulk RNA sequencing from fly heads of the same strain revealed that coexpression is a physical link in the form of abundant chimeric transposon-gene mRNAs. We identified 264 genes where transposons introduce cryptic splice sites into the nascent transcript and thereby significantly expand the neural transcript repertoire. Some genes exclusively produce chimeric mRNAs with transposon sequence; on average, 11.6% of the mRNAs produced from a given gene are chimeric. Conversely, most transposon-containing transcripts are chimeric, which suggests that somatic expression of these transposons is largely driven by cellular genes. We propose that chimeric mRNAs produced by alternative splicing into polymorphic transposons, rather than transposon mobilization, may contribute to functional differences between individual cells and animals.
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33
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Ilyin AA, Stolyarenko AD, Klenov MS, Shevelyov YY. Various modes of HP1a interactions with the euchromatic chromosome arms in Drosophila ovarian somatic cells. Chromosoma 2020; 129:201-214. [PMID: 32500264 DOI: 10.1007/s00412-020-00738-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 05/05/2020] [Accepted: 05/26/2020] [Indexed: 12/20/2022]
Abstract
Heterochromatin protein 1a (HP1a) is a well-known component of pericentromeric and telomeric heterochromatin in Drosophila. However, its role and the mechanisms of its binding in the chromosome arms (ChAs) remain largely unclear. Here, we identified HP1a-interacting domains in the somatic cells of Drosophila ovaries using a DamID-seq approach and compared them with insertion sites of transposable elements (TEs) revealed by genome sequencing. Although HP1a domains cover only 13% of ChAs, they non-randomly associate with 42% of TE insertions. Furthermore, HP1a on average propagates at 2-kb distances from the TE insertions. These data confirm the role of TEs in formation of HP1a islands in ChAs. However, only 18% of HP1a domains have adjacent TEs, indicating the existence of other mechanisms of HP1a domain formation besides spreading from TEs. In particular, many TE-independent HP1a domains correspond to the regions attached to the nuclear pore complexes (NPCs) or contain active gene promoters. However, HP1a occupancy on the promoters does not significantly influence expression of corresponding genes. At the same time, the steady-state transcript level of many genes located outside of HP1a domains was altered upon HP1a knockdown in the somatic cells of ovaries, thus pointing to the strong indirect effect of HP1a depletion. Collectively, our results support an existence of at least three different mechanisms of HP1a domain emergence in ChAs: spreading from TE insertions, transient interactions with the chromatin located near NPCs, and targeting to the promoters of moderately expressed genes.
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Affiliation(s)
- Artem A Ilyin
- Department of Molecular Genetics of Cell, Institute of Molecular Genetics, Russian Academy of Sciences, Kurchatov Sq. 2, Moscow, Russia, 123182
| | - Anastasia D Stolyarenko
- Department of Molecular Genetics of Cell, Institute of Molecular Genetics, Russian Academy of Sciences, Kurchatov Sq. 2, Moscow, Russia, 123182
| | - Mikhail S Klenov
- Department of Molecular Genetics of Cell, Institute of Molecular Genetics, Russian Academy of Sciences, Kurchatov Sq. 2, Moscow, Russia, 123182.
| | - Yuri Y Shevelyov
- Department of Molecular Genetics of Cell, Institute of Molecular Genetics, Russian Academy of Sciences, Kurchatov Sq. 2, Moscow, Russia, 123182.
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Miniature inverted-repeat transposable elements (MITEs), derived insertional polymorphism as a tool of marker systems for molecular plant breeding. Mol Biol Rep 2020; 47:3155-3167. [PMID: 32162128 DOI: 10.1007/s11033-020-05365-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 02/29/2020] [Indexed: 12/20/2022]
Abstract
Plant molecular breeding is expected to give significant gains in cultivar development through development and utilization of suitable molecular marker systems for genetic diversity analysis, rapid DNA fingerprinting, identification of true hybrids, trait mapping and marker-assisted selection. Transposable elements (TEs) are the most abundant component in a genome and being used as genetic markers in the plant molecular breeding. Here, we review on the high copious transposable element belonging to class-II DNA TEs called "miniature inverted-repeat transposable elements" (MITEs). MITEs are ubiquitous, short and non-autonomous DNA transposable elements which have a tendency to insert into genes and genic regions have paved a way for the development of functional DNA marker systems in plant genomes. This review summarises the characteristics of MITEs, principles and methodologies for development of MITEs based DNA markers, bioinformatics tools and resources for plant MITE discovery and their utilization in crop improvement.
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Evolution of Ty1 copy number control in yeast by horizontal transfer and recombination. PLoS Genet 2020; 16:e1008632. [PMID: 32084126 PMCID: PMC7055915 DOI: 10.1371/journal.pgen.1008632] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 03/04/2020] [Accepted: 01/27/2020] [Indexed: 01/04/2023] Open
Abstract
Transposable elements constitute a large fraction of most eukaryotic genomes. Insertion of mobile DNA sequences typically has deleterious effects on host fitness, and thus diverse mechanisms have evolved to control mobile element proliferation. Mobility of the Ty1 retrotransposon in Saccharomyces yeasts is regulated by copy number control (CNC) mediated by a self-encoded restriction factor derived from the Ty1 gag capsid gene that inhibits virus-like particle function. Here, we survey a panel of wild and human-associated strains of S. cerevisiae and S. paradoxus to investigate how genomic Ty1 content influences variation in Ty1 mobility. We observe high levels of mobility for a tester element with a gag sequence from the canonical Ty1 subfamily in permissive strains that either lack full-length Ty1 elements or only contain full-length copies of the Ty1' subfamily that have a divergent gag sequence. In contrast, low levels of canonical Ty1 mobility are observed in restrictive strains carrying full-length Ty1 elements containing a canonical gag sequence. Phylogenomic analysis of full-length Ty1 elements revealed that Ty1' is the ancestral subfamily present in wild strains of S. cerevisiae, and that canonical Ty1 in S. cerevisiae is a derived subfamily that acquired gag from S. paradoxus by horizontal transfer and recombination. Our results provide evidence that variation in the ability of S. cerevisiae and S. paradoxus strains to repress canonical Ty1 transposition via CNC is regulated by the genomic content of different Ty1 subfamilies, and that self-encoded forms of transposon control can spread across species boundaries by horizontal transfer.
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Vendrell-Mir P, Barteri F, Merenciano M, González J, Casacuberta JM, Castanera R. A benchmark of transposon insertion detection tools using real data. Mob DNA 2019; 10:53. [PMID: 31892957 PMCID: PMC6937713 DOI: 10.1186/s13100-019-0197-9] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Accepted: 12/17/2019] [Indexed: 02/01/2023] Open
Abstract
Background Transposable elements (TEs) are an important source of genomic variability in eukaryotic genomes. Their activity impacts genome architecture and gene expression and can lead to drastic phenotypic changes. Therefore, identifying TE polymorphisms is key to better understand the link between genotype and phenotype. However, most genotype-to-phenotype analyses have concentrated on single nucleotide polymorphisms as they are easier to reliable detect using short-read data. Many bioinformatic tools have been developed to identify transposon insertions from resequencing data using short reads. Nevertheless, the performance of most of these tools has been tested using simulated insertions, which do not accurately reproduce the complexity of natural insertions. Results We have overcome this limitation by building a dataset of insertions from the comparison of two high-quality rice genomes, followed by extensive manual curation. This dataset contains validated insertions of two very different types of TEs, LTR-retrotransposons and MITEs. Using this dataset, we have benchmarked the sensitivity and precision of 12 commonly used tools, and our results suggest that in general their sensitivity was previously overestimated when using simulated data. Our results also show that, increasing coverage leads to a better sensitivity but with a cost in precision. Moreover, we found important differences in tool performance, with some tools performing better on a specific type of TEs. We have also used two sets of experimentally validated insertions in Drosophila and humans and show that this trend is maintained in genomes of different size and complexity. Conclusions We discuss the possible choice of tools depending on the goals of the study and show that the appropriate combination of tools could be an option for most approaches, increasing the sensitivity while maintaining a good precision.
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Affiliation(s)
- Pol Vendrell-Mir
- 1Centre for Research in Agricultural Genomics CSIC-IRTA-UAB-UB, Campus UAB, Edifici CRAG, Bellaterra, 08193 Barcelona, Spain
| | - Fabio Barteri
- 1Centre for Research in Agricultural Genomics CSIC-IRTA-UAB-UB, Campus UAB, Edifici CRAG, Bellaterra, 08193 Barcelona, Spain
| | - Miriam Merenciano
- 2Institute of Evolutionary Biology (CSIC-Universitat Pompeu Fabra), Passeig Maritim Barceloneta 37-49, 08003 Barcelona, Spain
| | - Josefa González
- 2Institute of Evolutionary Biology (CSIC-Universitat Pompeu Fabra), Passeig Maritim Barceloneta 37-49, 08003 Barcelona, Spain
| | - Josep M Casacuberta
- 1Centre for Research in Agricultural Genomics CSIC-IRTA-UAB-UB, Campus UAB, Edifici CRAG, Bellaterra, 08193 Barcelona, Spain
| | - Raúl Castanera
- 1Centre for Research in Agricultural Genomics CSIC-IRTA-UAB-UB, Campus UAB, Edifici CRAG, Bellaterra, 08193 Barcelona, Spain
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A Deep Learning Approach for Detecting Copy Number Variation in Next-Generation Sequencing Data. G3-GENES GENOMES GENETICS 2019; 9:3575-3582. [PMID: 31455677 PMCID: PMC6829143 DOI: 10.1534/g3.119.400596] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Copy number variants (CNV) are associated with phenotypic variation in several species. However, properly detecting changes in copy numbers of sequences remains a difficult problem, especially in lower quality or lower coverage next-generation sequencing data. Here, inspired by recent applications of machine learning in genomics, we describe a method to detect duplications and deletions in short-read sequencing data. In low coverage data, machine learning appears to be more powerful in the detection of CNVs than the gold-standard methods of coverage estimation alone, and of equal power in high coverage data. We also demonstrate how replicating training sets allows a more precise detection of CNVs, even identifying novel CNVs in two genomes previously surveyed thoroughly for CNVs using long read data.
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Bast J, Jaron KS, Schuseil D, Roze D, Schwander T. Asexual reproduction reduces transposable element load in experimental yeast populations. eLife 2019; 8:48548. [PMID: 31486772 PMCID: PMC6783261 DOI: 10.7554/elife.48548] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Accepted: 09/04/2019] [Indexed: 01/04/2023] Open
Abstract
Theory predicts that sexual reproduction can either facilitate or restrain transposable element (TE) accumulation by providing TEs with a means of spreading to all individuals in a population, versus facilitating TE load reduction via purifying selection. By quantifying genomic TE loads over time in experimental sexual and asexual Saccharomyces cerevisiae populations, we provide direct evidence that TE loads decrease rapidly under asexual reproduction. We show, using simulations, that this reduction may occur via evolution of TE activity, most likely via increased excision rates. Thus, sex is a major driver of genomic TE loads and at the root of the success of TEs. The genetic information of most living organisms contains parasitic invaders known as transposable elements. These genetic sequences multiply by copying and pasting themselves through the genome, but this process can disrupt the activity of important genes and put the organism at risk. How transposable elements proliferate in a population depends on the way organisms reproduce. If they simply clone themselves asexually, the selfish elements cannot spread between the different clones. If the organisms mate together their respective transposable elements get mixed, which helps the sequences to spread more easily and to potentially become more virulent. However, sexual reproduction also comes with mechanisms that keep transposable elements in check. Bast, Jaron et al. took advantage of the fact that yeasts can reproduce with or without mating to explore whether sexual or asexual organisms are better at controlling the spread of transposable elements. The number of copies of transposable elements in the genomes of yeast grown sexually or asexually was assessed. The results showed that sexual populations kept constant numbers of selfish elements, while asexual organisms lost these genomic parasites over time. Simulations then revealed that this difference emerged because a defense gene that helps to delete transposable elements was spreading more quickly in the asexual group. The work by Bast, Jaron et al. therefore suggests that sex is responsible for the evolutionary success of transposable elements, while asexual populations can discard these sequences over time. Sex therefore helps genetic parasites, somewhat similar to sexually transmitted diseases, to spread between individuals and remain virulent.
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Affiliation(s)
- Jens Bast
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
| | - Kamil S Jaron
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland.,Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Donovan Schuseil
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
| | - Denis Roze
- UMI3614 Evolutionary Biology and Ecology of Alga, Centre National de la Recherche Scientifique (CNRS), Roscoff, France.,Station Biologique de Roscoff, Sorbonne Université, Roscoff, France
| | - Tanja Schwander
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
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Duc C, Yoth M, Jensen S, Mouniée N, Bergman CM, Vaury C, Brasset E. Trapping a somatic endogenous retrovirus into a germline piRNA cluster immunizes the germline against further invasion. Genome Biol 2019; 20:127. [PMID: 31227013 PMCID: PMC6587276 DOI: 10.1186/s13059-019-1736-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 06/11/2019] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND For species survival, the germline must faithfully transmit genetic information to the progeny. Transposable elements (TEs) constitute a significant threat to genome stability due to their mobility. In the metazoan germline, their mobilization is limited by a class of small RNAs called PIWI-interacting RNAs (piRNAs) produced by dedicated genomic loci called piRNA clusters. Although the piRNA pathway is an adaptive genomic immunity system, it remains unclear how the germline gains protection from a new transposon invasion. RESULTS To address this question, we analyze Drosophila melanogaster lines harboring a deletion within flamenco, a major piRNA cluster specifically expressed in somatic follicular cells. This deletion leads to derepression of the retrotransposon ZAM in the somatic follicular cells and subsequent germline genome invasion. In this mutant line, we identify de novo production of sense and antisense ZAM-derived piRNAs that display a germinal molecular signature. These piRNAs originated from a new ZAM insertion into a germline dual-strand piRNA cluster and silence ZAM expression specifically in germ cells. Finally, we find that ZAM trapping in a germinal piRNA cluster is a frequent event that occurs early during the isolation of the mutant line. CONCLUSIONS Transposons can hijack the host developmental process to propagate whenever their silencing is lost. Here, we show that the germline can protect itself by trapping invading somatic-specific TEs into germline piRNA clusters. This is the first demonstration of "auto-immunization" of a germline endangered by mobilization of a surrounding somatic TE.
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Affiliation(s)
- Céline Duc
- GReD, Université Clermont Auvergne, CNRS, INSERM, Faculté de Médecine, 63000 Clermont-Ferrand, France
- Present address: UFIP UMR-CNRS 6286, Epigénétique: prolifération et différenciation, Faculté des Sciences et des Techniques, 2 rue de la Houssinière, 44322 Nantes, France
| | - Marianne Yoth
- GReD, Université Clermont Auvergne, CNRS, INSERM, Faculté de Médecine, 63000 Clermont-Ferrand, France
| | - Silke Jensen
- GReD, Université Clermont Auvergne, CNRS, INSERM, Faculté de Médecine, 63000 Clermont-Ferrand, France
| | - Nolwenn Mouniée
- GReD, Université Clermont Auvergne, CNRS, INSERM, Faculté de Médecine, 63000 Clermont-Ferrand, France
| | - Casey M. Bergman
- Department of Genetics and Institute of Bioinformatics, University of Georgia, 120 E. Green St, Athens, GA 30602 USA
| | - Chantal Vaury
- GReD, Université Clermont Auvergne, CNRS, INSERM, Faculté de Médecine, 63000 Clermont-Ferrand, France
| | - Emilie Brasset
- GReD, Université Clermont Auvergne, CNRS, INSERM, Faculté de Médecine, 63000 Clermont-Ferrand, France
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Bourgeois Y, Boissinot S. On the Population Dynamics of Junk: A Review on the Population Genomics of Transposable Elements. Genes (Basel) 2019; 10:genes10060419. [PMID: 31151307 PMCID: PMC6627506 DOI: 10.3390/genes10060419] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 05/05/2019] [Accepted: 05/21/2019] [Indexed: 01/18/2023] Open
Abstract
Transposable elements (TEs) play an important role in shaping genomic organization and structure, and may cause dramatic changes in phenotypes. Despite the genetic load they may impose on their host and their importance in microevolutionary processes such as adaptation and speciation, the number of population genetics studies focused on TEs has been rather limited so far compared to single nucleotide polymorphisms (SNPs). Here, we review the current knowledge about the dynamics of transposable elements at recent evolutionary time scales, and discuss the mechanisms that condition their abundance and frequency. We first discuss non-adaptive mechanisms such as purifying selection and the variable rates of transposition and elimination, and then focus on positive and balancing selection, to finally conclude on the potential role of TEs in causing genomic incompatibilities and eventually speciation. We also suggest possible ways to better model TEs dynamics in a population genomics context by incorporating recent advances in TEs into the rich information provided by SNPs about the demography, selection, and intrinsic properties of genomes.
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Affiliation(s)
- Yann Bourgeois
- New York University Abu Dhabi, P.O. 129188, Saadiyat Island, Abu Dhabi, United Arab Emirates.
| | - Stéphane Boissinot
- New York University Abu Dhabi, P.O. 129188, Saadiyat Island, Abu Dhabi, United Arab Emirates.
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41
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Rech GE, Bogaerts-Márquez M, Barrón MG, Merenciano M, Villanueva-Cañas JL, Horváth V, Fiston-Lavier AS, Luyten I, Venkataram S, Quesneville H, Petrov DA, González J. Stress response, behavior, and development are shaped by transposable element-induced mutations in Drosophila. PLoS Genet 2019; 15:e1007900. [PMID: 30753202 PMCID: PMC6372155 DOI: 10.1371/journal.pgen.1007900] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Accepted: 12/16/2018] [Indexed: 11/30/2022] Open
Abstract
Most of the current knowledge on the genetic basis of adaptive evolution is based on the analysis of single nucleotide polymorphisms (SNPs). Despite increasing evidence for their causal role, the contribution of structural variants to adaptive evolution remains largely unexplored. In this work, we analyzed the population frequencies of 1,615 Transposable Element (TE) insertions annotated in the reference genome of Drosophila melanogaster, in 91 samples from 60 worldwide natural populations. We identified a set of 300 polymorphic TEs that are present at high population frequencies, and located in genomic regions with high recombination rate, where the efficiency of natural selection is high. The age and the length of these 300 TEs are consistent with relatively young and long insertions reaching high frequencies due to the action of positive selection. Besides, we identified a set of 21 fixed TEs also likely to be adaptive. Indeed, we, and others, found evidence of selection for 84 of these reference TE insertions. The analysis of the genes located nearby these 84 candidate adaptive insertions suggested that the functional response to selection is related with the GO categories of response to stimulus, behavior, and development. We further showed that a subset of the candidate adaptive TEs affects expression of nearby genes, and five of them have already been linked to an ecologically relevant phenotypic effect. Our results provide a more complete understanding of the genetic variation and the fitness-related traits relevant for adaptive evolution. Similar studies should help uncover the importance of TE-induced adaptive mutations in other species as well.
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Affiliation(s)
- Gabriel E. Rech
- Institute of Evolutionary Biology (IBE), CSIC-Universitat Pompeu Fabra, Barcelona, Spain
| | - María Bogaerts-Márquez
- Institute of Evolutionary Biology (IBE), CSIC-Universitat Pompeu Fabra, Barcelona, Spain
| | - Maite G. Barrón
- Institute of Evolutionary Biology (IBE), CSIC-Universitat Pompeu Fabra, Barcelona, Spain
| | - Miriam Merenciano
- Institute of Evolutionary Biology (IBE), CSIC-Universitat Pompeu Fabra, Barcelona, Spain
| | | | - Vivien Horváth
- Institute of Evolutionary Biology (IBE), CSIC-Universitat Pompeu Fabra, Barcelona, Spain
| | - Anna-Sophie Fiston-Lavier
- Institut des Sciences de l'Evolution de Montpellier (UMR 5554, CNRS-UM-IRD-EPHE), Université de Montpellier, Place Eugène Bataillon, Montpellier, France
| | | | - Sandeep Venkataram
- Department of Biology, Stanford University, Stanford, CA, United States of America
| | | | - Dmitri A. Petrov
- Department of Biology, Stanford University, Stanford, CA, United States of America
| | - Josefa González
- Institute of Evolutionary Biology (IBE), CSIC-Universitat Pompeu Fabra, Barcelona, Spain
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42
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Guio L, González J. New Insights on the Evolution of Genome Content: Population Dynamics of Transposable Elements in Flies and Humans. Methods Mol Biol 2019; 1910:505-530. [PMID: 31278675 DOI: 10.1007/978-1-4939-9074-0_16] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Understanding the abundance, diversity, and distribution of TEs in genomes is crucial to understand genome structure, function, and evolution. Advances in whole-genome sequencing techniques, as well as in bioinformatics tools, have increased our ability to detect and analyze the transposable element content in genomes. In addition to reference genomes, we now have access to population datasets in which multiple individuals within a species are sequenced. In this chapter, we highlight the recent advances in the study of TE population dynamics focusing on fruit flies and humans, which represent two extremes in terms of TE abundance, diversity, and activity. We review the most recent methodological approaches applied to the study of TE dynamics as well as the new knowledge on host factors involved in the regulation of TE activity. In addition to transposition rates, we also focus on TE deletion rates and on the selective forces that affect the dynamics of TEs in genomes.
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Affiliation(s)
- Lain Guio
- Institute of Evolutionary Biology (CSIC-Universitat Pompeu Fabra), Barcelona, Spain
| | - Josefa González
- Institute of Evolutionary Biology (CSIC-Universitat Pompeu Fabra), Barcelona, Spain.
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43
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Gramazio P, Yan H, Hasing T, Vilanova S, Prohens J, Bombarely A. Whole-Genome Resequencing of Seven Eggplant ( Solanum melongena) and One Wild Relative ( S. incanum) Accessions Provides New Insights and Breeding Tools for Eggplant Enhancement. FRONTIERS IN PLANT SCIENCE 2019; 10:1220. [PMID: 31649694 PMCID: PMC6791922 DOI: 10.3389/fpls.2019.01220] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2019] [Accepted: 09/04/2019] [Indexed: 05/20/2023]
Abstract
Whole-genome resequencing provides information of great relevance for crop genetics, evolution, and breeding. Here, we present the first whole-genome resequencing study using seven eggplant (Solanum melongena) and one wild relative (Solanum incanum) accessions. These eight accessions were selected for displaying a high phenotypic and genetic diversity and for being the founder parents of an eggplant multiparent advanced generation intercrosses population. By resequencing at an average depth of 19.8× and comparing to the high-quality reference genome "67/3" over 10 million high-reliable polymorphisms were discovered, of which over 9 million (84.5%) were single nucleotide polymorphisms and more than 700,000 (6.5%) InDels. However, while for the S. melongena accessions, the variants identified ranged from 0.8 to 1.3 million, over 9 million were detected for the wild S. incanum. This confirms the narrow genetic diversity of the domesticated eggplant and suggests that introgression breeding using wild relatives can efficiently contribute to broadening the genetic basis of this crop. Differences were observed among accessions for the enrichment in genes regulating important biological processes. By analyzing the distribution of the variants, we identified the potential footprints of old introgressions from wild relatives that can help to unravel the unclear domestication and breeding history. The comprehensive annotation of these eight genomes and the information provided in this study represents a landmark in eggplant genomics and allows the development of tools for eggplant genetics and breeding.
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Affiliation(s)
- Pietro Gramazio
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
- Instituto de Conservación y Mejora de la Agrodiversidad Valenciana, Universitat Politècnica de València, Valencia, Spain
- *Correspondence: Pietro Gramazio,
| | - Haidong Yan
- School of Plant and Environmental Sciences (SPES), Virginia Tech, Blacksburg, VA, United States
| | - Tomas Hasing
- School of Plant and Environmental Sciences (SPES), Virginia Tech, Blacksburg, VA, United States
| | - Santiago Vilanova
- Instituto de Conservación y Mejora de la Agrodiversidad Valenciana, Universitat Politècnica de València, Valencia, Spain
| | - Jaime Prohens
- Instituto de Conservación y Mejora de la Agrodiversidad Valenciana, Universitat Politècnica de València, Valencia, Spain
| | - Aureliano Bombarely
- School of Plant and Environmental Sciences (SPES), Virginia Tech, Blacksburg, VA, United States
- Department of Biosciences, Università degli Studi di Milano, Milan, Italy
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Bae J, Lee KW, Islam MN, Yim HS, Park H, Rho M. iMGEins: detecting novel mobile genetic elements inserted in individual genomes. BMC Genomics 2018; 19:944. [PMID: 30563451 PMCID: PMC6299635 DOI: 10.1186/s12864-018-5290-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Accepted: 11/20/2018] [Indexed: 11/10/2022] Open
Abstract
Background Recent advances in sequencing technology have allowed us to investigate personal genomes to find structural variations, which have been studied extensively to identify their association with the physiology of diseases such as cancer. In particular, mobile genetic elements (MGEs) are one of the major constituents of the human genomes, and cause genome instability by insertion, mutation, and rearrangement. Result We have developed a new program, iMGEins, to identify such novel MGEs by using sequencing reads of individual genomes, and to explore the breakpoints with the supporting reads and MGEs detected. iMGEins is the first MGE detection program that integrates three algorithmic components: discordant read-pair mapping, split-read mapping, and insertion sequence assembly. Our evaluation results showed its outstanding performance in detecting novel MGEs from simulated genomes, as well as real personal genomes. In detail, the average recall and precision rates of iMGEins are 96.67 and 100%, respectively, which are the highest among the programs compared. In the testing with real human genomes of the NA12878 sample, iMGEins shows the highest accuracy in detecting MGEs within 20 bp proximity of the breakpoints annotated. Conclusion In order to study the dynamics of MGEs in individual genomes, iMGEins was developed to accurately detect breakpoints and report inserted MGEs. Compared with other programs, iMGEins has valuable features of identifying novel MGEs and assembling the MGEs inserted. Electronic supplementary material The online version of this article (10.1186/s12864-018-5290-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Junwoo Bae
- Department of Electronics and Computer Engineering, Hanyang University, Seoul, Korea
| | - Kyeong Won Lee
- Marine Biotechnology Research Center, Korea Institute of Ocean Science and Technology, Ansan, Korea
| | - Mohammad Nazrul Islam
- Marine Biotechnology Research Center, Korea Institute of Ocean Science and Technology, Ansan, Korea.,Department of Marine Biotechnology, Korea University of Science and Technology, Daejeon, Korea.,Department of Biotechnology, Sher-e-Bangla Agricultural University, Dhaka, 1207, Bangladesh
| | - Hyung-Soon Yim
- Marine Biotechnology Research Center, Korea Institute of Ocean Science and Technology, Ansan, Korea.,Department of Marine Biotechnology, Korea University of Science and Technology, Daejeon, Korea
| | - Heejin Park
- Department of Computer Science and Engineering, Hanyang University, Seoul, Korea. .,Department of Biomedical Informatics, Hanyang University, Seoul, Korea.
| | - Mina Rho
- Department of Computer Science and Engineering, Hanyang University, Seoul, Korea. .,Department of Biomedical Informatics, Hanyang University, Seoul, Korea.
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45
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Sheppard AE, Stoesser N, German-Mesner I, Vegesana K, Sarah Walker A, Crook DW, Mathers AJ. TETyper: a bioinformatic pipeline for classifying variation and genetic contexts of transposable elements from short-read whole-genome sequencing data. Microb Genom 2018; 4:e000232. [PMID: 30465646 PMCID: PMC6412039 DOI: 10.1099/mgen.0.000232] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Accepted: 10/12/2018] [Indexed: 01/04/2023] Open
Abstract
Much of the worldwide dissemination of antibiotic resistance has been driven by resistance gene associations with mobile genetic elements (MGEs), such as plasmids and transposons. Although increasing, our understanding of resistance spread remains relatively limited, as methods for tracking mobile resistance genes through multiple species, strains and plasmids are lacking. We have developed a bioinformatic pipeline for tracking variation within, and mobility of, specific transposable elements (TEs), such as transposons carrying antibiotic-resistance genes. TETyper takes short-read whole-genome sequencing data as input and identifies single-nucleotide mutations and deletions within the TE of interest, to enable tracking of specific sequence variants, as well as the surrounding genetic context(s), to enable identification of transposition events. A major advantage of TETyper over previous methods is that it does not require a genome reference. To investigate global dissemination of Klebsiella pneumoniae carbapenemase (KPC) and its associated transposon Tn4401, we applied TETyper to a collection of over 3000 publicly available Illumina datasets containing blaKPC. This revealed surprising diversity, with over 200 distinct flanking genetic contexts for Tn4401, indicating high levels of transposition. Integration of sample metadata revealed insights into associations between geographic locations, host species, Tn4401 sequence variants and flanking genetic contexts. To demonstrate the ability of TETyper to cope with high-copy-number TEs and to track specific short-term evolutionary changes, we also applied it to the insertion sequence IS26 within a defined K. pneumoniae outbreak. TETyper is implemented in python and is freely available at https://github.com/aesheppard/TETyper.
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Affiliation(s)
- Anna E. Sheppard
- Nuffield Department of Medicine, University of Oxford, Oxford, UK
- National Institute for Health Research Health Protection Research Unit in Healthcare Associated Infections and Antimicrobial Resistance, University of Oxford, Oxford, UK
| | - Nicole Stoesser
- Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Ian German-Mesner
- Health Information & Technology, University of Virginia Health System, Charlottesville, Virginia, USA
| | - Kasi Vegesana
- Health Information & Technology, University of Virginia Health System, Charlottesville, Virginia, USA
| | - A. Sarah Walker
- Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Derrick W. Crook
- Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Amy J. Mathers
- Division of Infectious Disease and International Health, Department of Medicine, University of Virginia Health System, Charlottesville, Virginia, USA
- Clinical Microbiology Laboratory, Department of Pathology, University of Virginia Health System, Charlottesville, Virginia, USA
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Manee MM, Jackson J, Bergman CM. Conserved Noncoding Elements Influence the Transposable Element Landscape in Drosophila. Genome Biol Evol 2018; 10:1533-1545. [PMID: 29850787 PMCID: PMC6007792 DOI: 10.1093/gbe/evy104] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/22/2018] [Indexed: 12/15/2022] Open
Abstract
Highly conserved noncoding elements (CNEs) constitute a significant proportion of the genomes of multicellular eukaryotes. The function of most CNEs remains elusive, but growing evidence indicates they are under some form of purifying selection. Noncoding regions in many species also harbor large numbers of transposable element (TE) insertions, which are typically lineage specific and depleted in exons because of their deleterious effects on gene function or expression. However, it is currently unknown whether the landscape of TE insertions in noncoding regions is random or influenced by purifying selection on CNEs. Here, we combine comparative and population genomic data in Drosophila melanogaster to show that the abundance of TE insertions in intronic and intergenic CNEs is reduced relative to random expectation, supporting the idea that selective constraints on CNEs eliminate a proportion of TE insertions in noncoding regions. However, we find no evidence for differences in the allele frequency spectra for polymorphic TE insertions in CNEs versus those in unconstrained spacer regions, suggesting that the distribution of fitness effects acting on observable TE insertions is similar across different functional compartments in noncoding DNA. Our results provide evidence that selective constraints on CNEs contribute to shaping the landscape of TE insertion in eukaryotic genomes, and provide further evidence that CNEs are indeed functionally constrained and not simply mutational cold spots.
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Affiliation(s)
- Manee M Manee
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom.,National Center for Biotechnology, King Abdulaziz City for Science and Technology, Riyadh, Saudi Arabia.,Center of Excellence for Genomics (CEG), King Abdulaziz City for Science and Technology, Riyadh, Saudi Arabia
| | - John Jackson
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom.,Department of Animal and Plant Sciences, University of Sheffield, Sheffield, United Kingdom
| | - Casey M Bergman
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom.,Department of Genetics, University of Georgia, Athens, GA.,Institute of Bioinformatics, University of Georgia, Athens, GA
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Horizontal transfer and proliferation of Tsu4 in Saccharomyces paradoxus. Mob DNA 2018; 9:18. [PMID: 29942366 PMCID: PMC5998506 DOI: 10.1186/s13100-018-0122-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Accepted: 05/31/2018] [Indexed: 11/10/2022] Open
Abstract
Background Recent evidence suggests that horizontal transfer plays a significant role in the evolution of of transposable elements (TEs) in eukaryotes. Many cases of horizontal TE transfer (HTT) been reported in animals and plants, however surprisingly few examples of HTT have been reported in fungi. Findings Here I report evidence for a novel HTT event in fungi involving Tsu4 in Saccharomyces paradoxus based on (i) unexpectedly high similarity between Tsu4 elements in S. paradoxus and S. uvarum, (ii) a patchy distribution of Tsu4 in S. paradoxus and general absence from its sister species S. cerevisiae, and (iii) discordance between the phylogenetic history of Tsu4 sequences and species in the Saccharomyces sensu stricto group. Available data suggests the HTT event likely occurred somewhere in the Nearctic, Neotropic or Indo-Australian part of the S. paradoxus species range, and that a lineage related to S. uvarum or S. eubayanus was the likely donor species. The HTT event has led to massive proliferation of Tsu4 in the South American lineage of S. paradoxus, which exhibits partial reproductive isolation with other strains of this species because of multiple reciprocal translocations. Full-length Tsu4 elements are associated with both breakpoints of one of these reciprocal translocations. Conclusions This work shows that comprehensive analysis of TE sequences in essentially-complete genome assemblies derived from long-read sequencing provides new opportunities to detect HTT events in fungi and other organisms. This work also provides support for the hypothesis that HTT and subsequent TE proliferation can induce genome rearrangements that contribute to post-zygotic isolation in yeast. Electronic supplementary material The online version of this article (10.1186/s13100-018-0122-7) contains supplementary material, which is available to authorized users.
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Abstract
In the course of analyzing whole-genome data, it is common practice to mask or filter out repetitive regions of a genome, such as transposable elements and endogenous retroviruses, in order to focus only on genes and thus simplify the results. This Commentary is a plea from one member of the Mobile DNA community to all gene-centric researchers: please do not ignore the repetitive fraction of the genome. Please stop narrowing your findings by only analyzing a minority of the genome, and instead broaden your analyses to include the rich biology of repetitive and mobile DNA. In this article, I present four arguments supporting a case for retaining repetitive DNA in your genome-wide analysis.
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Affiliation(s)
- R Keith Slotkin
- Department of Molecular Genetics and Center for Applied Plant Sciences, The Ohio State University, 500 Aronoff Laboratory, 318 West 12th Ave, Columbus, Ohio 43210 USA
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Kofler R. SimulaTE: simulating complex landscapes of transposable elements of populations. Bioinformatics 2018; 34:1419-1420. [PMID: 29186298 PMCID: PMC5905622 DOI: 10.1093/bioinformatics/btx772] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 10/11/2017] [Accepted: 11/25/2017] [Indexed: 11/14/2022] Open
Abstract
Motivation Estimating the abundance of transposable elements (TEs) in populations (or tissues) promises to answer many open research questions. However, progress is hampered by the lack of concordance between different approaches for TE identification and thus potentially unreliable results. Results To address this problem, we developed SimulaTE a tool that generates TE landscapes for populations using a newly developed domain specific language (DSL). The simple syntax of our DSL allows for easily building even complex TE landscapes that have, for example, nested, truncated and highly diverged TE insertions. Reads may be simulated for the populations using different sequencing technologies (PacBio, Illumina paired-ends) and strategies (sequencing individuals and pooled populations). The comparison between the expected (i.e. simulated) and the observed results will guide researchers in finding the most suitable approach for a particular research question. Availability and implementation SimulaTE is implemented in Python and available at https://sourceforge.net/projects/simulates/. Manual https://sourceforge.net/p/simulates/wiki/Home/#manual; Test data and tutorials https://sourceforge.net/p/simulates/wiki/Home/#walkthrough; Validation https://sourceforge.net/p/simulates/wiki/Home/#validation. Contact robert.kofler@vetmeduni.ac.at.
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Affiliation(s)
- Robert Kofler
- Institute für Populationsgenetik, Vetmeduni Vienna, Wien, Austria
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