1
|
Pezenti LF, Dionisio JF, Sosa-Gómez DR, de Souza RF, da Rosa R. Transposable elements in the transcriptome of the velvetbean caterpillar Anticarsia gemmatalis Hübner, 1818 (Lepidoptera: Erebidae). Genome 2023. [DOI: 10.1139/gen-2022-0066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/29/2023]
Abstract
Transposable elements (TEs) are DNA sequences that possess the ability to move from one genomic location to another. These sequences contribute to a significant fraction of the genomes of most eukaryotes and can impact their architecture and regulation. In this paper, we present the first data related to the identification and characterization of TEs present in the transcriptome of Anticarsia gemmatalis. Approximately, 835 transcripts showed significant similarity to TEs and (or) characteristic domains. Retrotransposons accounted for 71.2% (595 sequences) of the identified elements, while DNA transposons were less abundant, with 240 annotations (28.8%). TEs were classified into 30 superfamilies, with SINE3/5S and Gypsy being the most abundant. Based on the sequences of TEs found in the transcriptome, we were able to locate conserved regions in the chromosomes of this species. The analysis of differential expression of TEs in susceptible and resistant strains, challenged and not challenged with Bacillus thuringiensis ( Bt) from in silico analysis, indicated that exposure to Bt can regulate the transcription of mobile genetic elements in the velvetbean caterpillar. Thus, these data contribute significantly to the knowledge of the structure and composition of these elements in the genome of this species, and suggest the role of stress on their expression.
Collapse
|
2
|
Vargas-Chavez C, Longo Pendy NM, Nsango SE, Aguilera L, Ayala D, González J. Transposable element variants and their potential adaptive impact in urban populations of the malaria vector Anopheles coluzzii. Genome Res 2021; 32:189-202. [PMID: 34965939 PMCID: PMC8744685 DOI: 10.1101/gr.275761.121] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 11/24/2021] [Indexed: 11/28/2022]
Abstract
Anopheles coluzzii is one of the primary vectors of human malaria in sub-Saharan Africa. Recently, it has spread into the main cities of Central Africa threatening vector control programs. The adaptation of An. coluzzii to urban environments partly results from an increased tolerance to organic pollution and insecticides. Some of the molecular mechanisms for ecological adaptation are known, but the role of transposable elements (TEs) in the adaptive processes of this species has not been studied yet. As a first step toward assessing the role of TEs in rapid urban adaptation, we sequenced using long reads six An. coluzzii genomes from natural breeding sites in two major Central Africa cities. We de novo annotated TEs in these genomes and in an additional high-quality An. coluzzii genome, and we identified 64 new TE families. TEs were nonrandomly distributed throughout the genome with significant differences in the number of insertions of several superfamilies across the studied genomes. We identified seven putatively active families with insertions near genes with functions related to vectorial capacity, and several TEs that may provide promoter and transcription factor binding sites to insecticide resistance and immune-related genes. Overall, the analysis of multiple high-quality genomes allowed us to generate the most comprehensive TE annotation in this species to date and identify several TE insertions that could potentially impact both genome architecture and the regulation of functionally relevant genes. These results provide a basis for future studies of the impact of TEs on the biology of An. coluzzii.
Collapse
Affiliation(s)
- Carlos Vargas-Chavez
- Institute of Evolutionary Biology (CSIC-Universitat Pompeu Fabra), 08003 Barcelona, Spain
| | - Neil Michel Longo Pendy
- Centre Interdisciplinaire de Recherches Médicales de Franceville (CIRMF), BP 769, Franceville, Gabon.,École Doctorale Régional (EDR) en Infectiologie Tropicale d'Afrique Centrale, BP 876, Franceville, Gabon
| | - Sandrine E Nsango
- Faculté de Médecine et des Sciences Pharmaceutiques, Université de Douala, BP 2701, Douala, Cameroun
| | - Laura Aguilera
- Institute of Evolutionary Biology (CSIC-Universitat Pompeu Fabra), 08003 Barcelona, Spain
| | - Diego Ayala
- Centre Interdisciplinaire de Recherches Médicales de Franceville (CIRMF), BP 769, Franceville, Gabon.,Maladies Infectieuses et Vecteurs: Ecologie, Génétique, Evolution et Contrôle (MIVEGEC), Université Montpellier, CNRS, IRD, 64501 Montpellier, France
| | - Josefa González
- Institute of Evolutionary Biology (CSIC-Universitat Pompeu Fabra), 08003 Barcelona, Spain
| |
Collapse
|
3
|
Palazzo A, Marsano RM. Transposable elements: a jump toward the future of expression vectors. Crit Rev Biotechnol 2021; 41:792-808. [PMID: 33622117 DOI: 10.1080/07388551.2021.1888067] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Expression vectors (EVs) are artificial nucleic acid molecules with a modular structure that allows for the transcription of DNA sequences of interest in either cellular or cell-free environments. These vectors have emerged as cross-disciplinary tools with multiple applications in an expanding Life Sciences market. The cis-regulatory sequences (CRSs) that control the transcription in EVs are typically sourced from either viruses or from characterized genes. However, the recent advancement in transposable elements (TEs) technology provides attractive alternatives that may enable a significant improvement in the design of EVs. Commonly known as "jumping genes," due to their ability to move between genetic loci, TEs are constitutive components of both eukaryotic and prokaryotic genomes. TEs harbor native CRSs that allow the regulated transcription of transposition-related genes. However, some TE-related CRSs display striking characteristics, which provides the opportunity to reconsider TEs as lead actors in the design of EVs. In this article, we provide a synopsis of the transcriptional control elements commonly found in EVs together with an extensive discussion of their advantages and limitations. We also highlight the latest findings that may allow for the implementation of TE-derived sequences in the EVs feasible, possibly improving existing vectors. By introducing this new concept of TEs as a source of regulatory sequences, we aim to stimulate a profitable discussion of the potential advantages and benefits of developing a new generation of EVs based on the use of TE-derived control sequences.
Collapse
Affiliation(s)
- Antonio Palazzo
- Laboratory of Translational Nanotechnology, "Istituto Tumori Giovanni Paolo II" I.R.C.C.S, Bari, Italy
| | | |
Collapse
|
4
|
Palazzo A, Escuder E, D'Addabbo P, Lovero D, Marsano RM. A genomic survey of Tc1-mariner transposons in nematodes suggests extensive horizontal transposon transfer events. Mol Phylogenet Evol 2021; 158:107090. [PMID: 33545274 DOI: 10.1016/j.ympev.2021.107090] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 01/27/2021] [Accepted: 01/27/2021] [Indexed: 01/24/2023]
Abstract
The number of reports concerning horizontal transposon transfers (HTT) in metazoan species is considerably increased, alongside with the exponential growth of genomic sequence data However, our understanding of the mechanisms of such phenomenon is still at an early stage. Nematodes constitute an animal phylum successfully adapted to almost every ecosystem and for this reason could potentially contribute to spreading the genetic information through horizontal transfer. To date, few studies describe HTT of nematode retrotransposons. This is due to the lack of annotation of transposable elements in the sequenced nematode genomes, especially DNA transposons, which are acknowledged as the best horizontal travelers among mobile sequences. We have therefore started a survey of DNA transposons and their possible involvement in HTT in sequenced nematode genomes. Here, we describe 83 new Tc1/mariner elements distributed in 17 nematode species. Among them, nine families were possibly horizontally transferred between nematodes and the most diverse animal species, including ants as preferred partner of HTT. The results obtained suggest that HTT events involving nematodes Tc1/mariner elements are not uncommon, and that nematodes could have a possible role as transposon reservoir that, in turn, can be redistributed among animal genomes. Overall, this could be relevant to understand how the inter-species genetic flows shape the landscape of genetic variation of organisms inhabiting specific environmental communities.
Collapse
Affiliation(s)
- Antonio Palazzo
- Dipartimento di Biologia, Università degli Studi di Bari "Aldo Moro", Bari, Italy
| | - Elsa Escuder
- Dipartimento di Biologia, Università degli Studi di Bari "Aldo Moro", Bari, Italy
| | - Pietro D'Addabbo
- Dipartimento di Biologia, Università degli Studi di Bari "Aldo Moro", Bari, Italy
| | - Domenica Lovero
- Dipartimento di Scienze Biomediche ed Oncologia Umana (DIMO), Università degli Studi di Bari "Aldo Moro", Bari, Italy
| | | |
Collapse
|
5
|
de Melo ES, Wallau GL. Mosquito genomes are frequently invaded by transposable elements through horizontal transfer. PLoS Genet 2020; 16:e1008946. [PMID: 33253164 PMCID: PMC7728395 DOI: 10.1371/journal.pgen.1008946] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 12/10/2020] [Accepted: 10/19/2020] [Indexed: 12/28/2022] Open
Abstract
Transposable elements (TEs) are mobile genetic elements that parasitize basically all eukaryotic species genomes. Due to their complexity, an in-depth TE characterization is only available for a handful of model organisms. In the present study, we performed a de novo and homology-based characterization of TEs in the genomes of 24 mosquito species and investigated their mode of inheritance. More than 40% of the genome of Aedes aegypti, Aedes albopictus, and Culex quinquefasciatus is composed of TEs, while it varied substantially among Anopheles species (0.13%-19.55%). Class I TEs are the most abundant among mosquitoes and at least 24 TE superfamilies were found. Interestingly, TEs have been extensively exchanged by horizontal transfer (172 TE families of 16 different superfamilies) among mosquitoes in the last 30 million years. Horizontally transferred TEs represents around 7% of the genome in Aedes species and a small fraction in Anopheles genomes. Most of these horizontally transferred TEs are from the three ubiquitous LTR superfamilies: Gypsy, Bel-Pao and Copia. Searching more than 32,000 genomes, we also uncovered transfers between mosquitoes and two different Phyla-Cnidaria and Nematoda-and two subphyla-Chelicerata and Crustacea, identifying a vector, the worm Wuchereria bancrofti, that enabled the horizontal spread of a Tc1-mariner element among various Anopheles species. These data also allowed us to reconstruct the horizontal transfer network of this TE involving more than 40 species. In summary, our results suggest that TEs are frequently exchanged by horizontal transfers among mosquitoes, influencing mosquito's genome size and variability.
Collapse
Affiliation(s)
- Elverson Soares de Melo
- Department of Entomology, Aggeu Magalhães Institute–Oswaldo Cruz Foundation (Fiocruz), Recife, Pernambuco, Brazil
| | - Gabriel Luz Wallau
- Department of Entomology, Aggeu Magalhães Institute–Oswaldo Cruz Foundation (Fiocruz), Recife, Pernambuco, Brazil
| |
Collapse
|
6
|
Gamez S, Srivastav S, Akbari OS, Lau NC. Diverse Defenses: A Perspective Comparing Dipteran Piwi-piRNA Pathways. Cells 2020; 9:E2180. [PMID: 32992598 PMCID: PMC7601171 DOI: 10.3390/cells9102180] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 09/22/2020] [Accepted: 09/23/2020] [Indexed: 02/07/2023] Open
Abstract
Animals face the dual threat of virus infections hijacking cellular function and transposons proliferating in germline genomes. For insects, the deeply conserved RNA interference (RNAi) pathways and other chromatin regulators provide an important line of defense against both viruses and transposons. For example, this innate immune system displays adaptiveness to new invasions by generating cognate small RNAs for targeting gene silencing measures against the viral and genomic intruders. However, within the Dipteran clade of insects, Drosophilid fruit flies and Culicids mosquitoes have evolved several unique mechanistic aspects of their RNAi defenses to combat invading transposons and viruses, with the Piwi-piRNA arm of the RNAi pathways showing the greatest degree of novel evolution. Whereas central features of Piwi-piRNA pathways are conserved between Drosophilids and Culicids, multiple lineage-specific innovations have arisen that may reflect distinct genome composition differences and specific ecological and physiological features dividing these two branches of Dipterans. This perspective review focuses on the most recent findings illuminating the Piwi/piRNA pathway distinctions between fruit flies and mosquitoes, and raises open questions that need to be addressed in order to ameliorate human diseases caused by pathogenic viruses that mosquitoes transmit as vectors.
Collapse
Affiliation(s)
- Stephanie Gamez
- Division of Biological Sciences, Section of Cell and Developmental Biology, University of California, San Diego, CA 92093, USA; (S.G.); (O.S.A.)
| | - Satyam Srivastav
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853-2703, USA;
| | - Omar S. Akbari
- Division of Biological Sciences, Section of Cell and Developmental Biology, University of California, San Diego, CA 92093, USA; (S.G.); (O.S.A.)
| | - Nelson C. Lau
- Department of Biochemistry and Genome Science Institute, Boston University School of Medicine, Boston, MA 02118, USA
| |
Collapse
|
7
|
Xuan N, Rajashekar B, Picimbon JF. DNA and RNA-dependent polymerization in editing of Bombyx chemosensory protein (CSP) gene family. ACTA ACUST UNITED AC 2019. [DOI: 10.1016/j.aggene.2019.100087] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
|
8
|
Coughlan AY, Wolfe KH. The reported point centromeres of
Scheffersomyces stipitis
are retrotransposon long terminal repeats. Yeast 2019; 36:275-283. [DOI: 10.1002/yea.3375] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 11/20/2018] [Accepted: 12/10/2018] [Indexed: 12/25/2022] Open
Affiliation(s)
- Aisling Y. Coughlan
- UCD Conway Institute, School of MedicineUniversity College Dublin Dublin 4 Ireland
| | - Kenneth H. Wolfe
- UCD Conway Institute, School of MedicineUniversity College Dublin Dublin 4 Ireland
| |
Collapse
|
9
|
Fernández-Medina RD, Carareto CMA, Struchiner CJ, Ribeiro JMC. Transposable elements in the Anopheles funestus transcriptome. Genetica 2017; 145:275-293. [PMID: 28424974 DOI: 10.1007/s10709-017-9964-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2016] [Accepted: 03/27/2017] [Indexed: 12/27/2022]
Abstract
Transposable elements (TEs) are present in most of the eukaryotic genomes and their impact on genome evolution is increasingly recognized. Although there is extensive information on the TEs present in several eukaryotic genomes, less is known about the expression of these elements at the transcriptome level. Here we present a detailed analysis regarding the expression of TEs in Anopheles funestus, the second most important vector of human malaria in Africa. Several transcriptionally active TE families belonging both to Class I and II were identified and characterized. Interestingly, we have identified a full-length putative active element (including the presence of full length TIRs in the genomic sequence) belonging to the hAT superfamily, which presents active members in other insect genomes. This work contributes to a comprehensive understanding of the landscape of transposable elements in A. funestus transcriptome. Our results reveal that TEs are abundant and diverse in the mosquito and that most of the TE families found in the genome are represented in the mosquito transcriptome, a fact that could indicate activity of these elements.The vast diversity of TEs expressed in A. funestus suggests that there is ongoing amplification of several families in this organism.
Collapse
Affiliation(s)
- Rita D Fernández-Medina
- Fundação Oswaldo Cruz, Escola Nacional de Saúde Pública, Av. Brasil, 4365, Rio de Janeiro, Brazil.
| | - Claudia M A Carareto
- Departamento de Biologia, UNESP-Universidade Estadual Paulista, Rua Cristóvão Colombo, 2265, São José do Rio Preto, SP, Brazil
| | - Cláudio J Struchiner
- Fundação Oswaldo Cruz, Escola Nacional de Saúde Pública, Av. Brasil, 4365, Rio de Janeiro, Brazil
| | - José M C Ribeiro
- Laboratory of Malaria and Vector Research, NIAID/NIH, Rockville, MD, 20852, USA
| |
Collapse
|
10
|
Glukhov IA, Kotnova AP, Stefanov YE, Ilyin YV. The first complete Mag family retrotransposons discovered in Drosophila. DOKL BIOCHEM BIOPHYS 2016; 466:1-4. [PMID: 27025475 DOI: 10.1134/s1607672916010014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Indexed: 11/23/2022]
Abstract
A retrotransposon of the Mag family was found in the Drosophila simulans genome for the first time. We also identified novel transposable elements representing the Mag family in seven Drosophila species. The high similarity between the 3' and 5' long terminal repeats in the found copies of transposable elements indicates that their retrotransposition has occurred relatively recently. Thus, the Mag family of retrotransposons is quite common for the genus Drosophila.
Collapse
Affiliation(s)
- I A Glukhov
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, ul. Vavilova 32, Moscow, 119991, Russia.
| | - A P Kotnova
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, ul. Vavilova 32, Moscow, 119991, Russia
| | - Y E Stefanov
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, ul. Vavilova 32, Moscow, 119991, Russia
| | - Y V Ilyin
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, ul. Vavilova 32, Moscow, 119991, Russia.,Institute of Gene Biology, Russian Academy of Sciences, ul. Vavilova 34/5, Moscow, 119334, Russia
| |
Collapse
|
11
|
Kutsenko A, Svensson T, Nystedt B, Lundeberg J, Björk P, Sonnhammer E, Giacomello S, Visa N, Wieslander L. The Chironomus tentans genome sequence and the organization of the Balbiani ring genes. BMC Genomics 2014; 15:819. [PMID: 25261295 PMCID: PMC4192438 DOI: 10.1186/1471-2164-15-819] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Accepted: 09/22/2014] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND The polytene nuclei of the dipteran Chironomus tentans (Ch. tentans) with their Balbiani ring (BR) genes constitute an exceptional model system for studies of the expression of endogenous eukaryotic genes. Here, we report the first draft genome of Ch. tentans and characterize its gene expression machineries and genomic architecture of the BR genes. RESULTS The genome of Ch. tentans is approximately 200 Mb in size, and has a low GC content (31%) and a low repeat fraction (15%) compared to other Dipteran species. Phylogenetic inference revealed that Ch. tentans is a sister clade to mosquitoes, with a split 150-250 million years ago. To characterize the Ch. tentans gene expression machineries, we identified potential orthologus sequences to more than 600 Drosophila melanogaster (D. melanogaster) proteins involved in the expression of protein-coding genes. We report novel data on the organization of the BR gene loci, including a novel putative BR gene, and we present a model for the organization of chromatin bundles in the BR2 puff based on genic and intergenic in situ hybridizations. CONCLUSIONS We show that the molecular machineries operating in gene expression are largely conserved between Ch. tentans and D. melanogaster, and we provide enhanced insight into the organization and expression of the BR genes. Our data strengthen the generality of the BR genes as a unique model system and provide essential background for in-depth studies of the biogenesis of messenger ribonucleoprotein complexes.
Collapse
Affiliation(s)
- Alexey Kutsenko
- />Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, SE 106 91 Stockholm, Sweden
- />Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, SE 171 21 Solna, Sweden
| | - Thomas Svensson
- />Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, SE 171 21 Solna, Sweden
| | - Björn Nystedt
- />Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, SE 171 21 Solna, Sweden
- />Science for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, SE 752 37 Uppsala, Sweden
| | - Joakim Lundeberg
- />Science for Life Laboratory, KTH, Royal Institute of Technology, Science for Life Laboratory, SE 171 65 Solna, Sweden
| | - Petra Björk
- />Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, SE 106 91 Stockholm, Sweden
| | - Erik Sonnhammer
- />Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, SE 171 21 Solna, Sweden
- />Department of Biochemistry and Biophysics, Stockholm University, SE 106 91 Stockholm, Sweden
| | - Stefania Giacomello
- />Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, SE 171 21 Solna, Sweden
| | - Neus Visa
- />Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, SE 106 91 Stockholm, Sweden
| | - Lars Wieslander
- />Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, SE 106 91 Stockholm, Sweden
| |
Collapse
|
12
|
Steinbiss S, Kastens S, Kurtz S. LTRsift: a graphical user interface for semi-automatic classification and postprocessing of de novo detected LTR retrotransposons. Mob DNA 2012; 3:18. [PMID: 23131050 PMCID: PMC3582472 DOI: 10.1186/1759-8753-3-18] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Accepted: 08/31/2012] [Indexed: 11/30/2022] Open
Abstract
Background Long terminal repeat (LTR) retrotransposons are a class of eukaryotic mobile elements characterized by a distinctive sequence similarity-based structure. Hence they are well suited for computational identification. Current software allows for a comprehensive genome-wide de novo detection of such elements. The obvious next step is the classification of newly detected candidates resulting in (super-)families. Such a de novo classification approach based on sequence-based clustering of transposon features has been proposed before, resulting in a preliminary assignment of candidates to families as a basis for subsequent manual refinement. However, such a classification workflow is typically split across a heterogeneous set of glue scripts and generic software (for example, spreadsheets), making it tedious for a human expert to inspect, curate and export the putative families produced by the workflow. Results We have developed LTRsift, an interactive graphical software tool for semi-automatic postprocessing of de novo predicted LTR retrotransposon annotations. Its user-friendly interface offers customizable filtering and classification functionality, displaying the putative candidate groups, their members and their internal structure in a hierarchical fashion. To ease manual work, it also supports graphical user interface-driven reassignment, splitting and further annotation of candidates. Export of grouped candidate sets in standard formats is possible. In two case studies, we demonstrate how LTRsift can be employed in the context of a genome-wide LTR retrotransposon survey effort. Conclusions LTRsift is a useful and convenient tool for semi-automated classification of newly detected LTR retrotransposons based on their internal features. Its efficient implementation allows for convenient and seamless filtering and classification in an integrated environment. Developed for life scientists, it is helpful in postprocessing and refining the output of software for predicting LTR retrotransposons up to the stage of preparing full-length reference sequence libraries. The LTRsift software is freely available at
http://www.zbh.uni-hamburg.de/LTRsift under an open-source license.
Collapse
Affiliation(s)
- Sascha Steinbiss
- Center for Bioinformatics, University of Hamburg, 20146 Hamburg, Bundesstrasse 43, Germany.
| | | | | |
Collapse
|