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Weghorst F, Torres Marcén M, Faridi G, Lee YCG, Cramer KS. Deep Conservation and Unexpected Evolutionary History of Neighboring lncRNAs MALAT1 and NEAT1. J Mol Evol 2024; 92:30-41. [PMID: 38189925 PMCID: PMC10869381 DOI: 10.1007/s00239-023-10151-y] [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: 06/15/2023] [Accepted: 11/29/2023] [Indexed: 01/09/2024]
Abstract
Long non-coding RNAs (lncRNAs) have begun to receive overdue attention for their regulatory roles in gene expression and other cellular processes. Although most lncRNAs are lowly expressed and tissue-specific, notable exceptions include MALAT1 and its genomic neighbor NEAT1, two highly and ubiquitously expressed oncogenes with roles in transcriptional regulation and RNA splicing. Previous studies have suggested that NEAT1 is found only in mammals, while MALAT1 is present in all gnathostomes (jawed vertebrates) except birds. Here we show that these assertions are incomplete, likely due to the challenges associated with properly identifying these two lncRNAs. Using phylogenetic analysis and structure-aware annotation of publicly available genomic and RNA-seq coverage data, we show that NEAT1 is a common feature of tetrapod genomes except birds and squamates. Conversely, we identify MALAT1 in representative species of all major gnathostome clades, including birds. Our in-depth examination of MALAT1, NEAT1, and their genomic context in a wide range of vertebrate species allows us to reconstruct the series of events that led to the formation of the locus containing these genes in taxa from cartilaginous fish to mammals. This evolutionary history includes the independent loss of NEAT1 in birds and squamates, since NEAT1 is found in the closest living relatives of both clades (crocodilians and tuataras, respectively). These data clarify the origins and relationships of MALAT1 and NEAT1 and highlight an opportunity to study the change and continuity in lncRNA structure and function over deep evolutionary time.
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Affiliation(s)
- Forrest Weghorst
- Department of Neurobiology and Behavior, University of California, Irvine, USA
| | - Martí Torres Marcén
- Department of Neurobiology and Behavior, University of California, Irvine, USA
| | - Garrison Faridi
- Department of Neurobiology and Behavior, University of California, Irvine, USA
| | - Yuh Chwen G Lee
- Department of Ecology and Evolutionary Biology, University of California, Irvine, USA
| | - Karina S Cramer
- Department of Neurobiology and Behavior, University of California, Irvine, USA.
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2
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Segal D, Coulombe S, Sim J, Dostie J. A conserved HOTAIRM1-HOXA1 regulatory axis contributes early to neuronal differentiation. RNA Biol 2023; 20:1523-1539. [PMID: 37743644 PMCID: PMC10619521 DOI: 10.1080/15476286.2023.2258028] [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] [Accepted: 04/03/2023] [Indexed: 09/26/2023] Open
Abstract
HOTAIRM1 is unlike most long non-coding RNAs in that its sequence is highly conserved across mammals. Such evolutionary conservation points to it having a role in key cellular processes. We previously reported that HOTAIRM1 is required to curb premature activation of downstream HOXA genes in a cell model recapitulating their sequential induction during development. We found that it regulates 3' HOXA gene expression by a mechanism involving epigenetic and three-dimensional chromatin changes. Here we show that HOTAIRM1 participates in proper progression through the early stages of neuronal differentiation. We found that it can associate with the HOXA1 transcription factor and contributes to its downstream transcriptional program. Particularly, HOTAIRM1 affects the NANOG/POU5F1/SOX2 core pluripotency network maintaining an undifferentiated cell state. HOXA1 depletion similarly perturbed expression of these pluripotent factors, suggesting that HOTAIRM1 is a modulator of this transcription factor pathway. Also, given that binding of HOTAIRM1 to HOXA1 was observed in different cell types and species, our results point to this ribonucleoprotein complex as an integral part of a conserved HOTAIRM1-HOXA1 regulatory axis modulating the transition from a pluripotent to a differentiated neuronal state.
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Affiliation(s)
- Dana Segal
- Department of Biochemistry, and Rosalind & Morris Goodman Cancer Institute, McGill University, Montréal, Québec, Canada
| | - Samy Coulombe
- Department of Biochemistry, and Rosalind & Morris Goodman Cancer Institute, McGill University, Montréal, Québec, Canada
- School of Computer Science, and McGill Center for Bioinformatics, McGill University, Montréal, Québec, Canada
| | - Jasper Sim
- Department of Biochemistry, and Rosalind & Morris Goodman Cancer Institute, McGill University, Montréal, Québec, Canada
| | - Josée Dostie
- Department of Biochemistry, and Rosalind & Morris Goodman Cancer Institute, McGill University, Montréal, Québec, Canada
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3
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Brasó-Vives M, Marlétaz F, Echchiki A, Mantica F, Acemel RD, Gómez-Skarmeta JL, Hartasánchez DA, Le Targa L, Pontarotti P, Tena JJ, Maeso I, Escriva H, Irimia M, Robinson-Rechavi M. Parallel evolution of amphioxus and vertebrate small-scale gene duplications. Genome Biol 2022; 23:243. [PMID: 36401278 PMCID: PMC9673378 DOI: 10.1186/s13059-022-02808-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 10/31/2022] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Amphioxus are non-vertebrate chordates characterized by a slow morphological and molecular evolution. They share the basic chordate body-plan and genome organization with vertebrates but lack their 2R whole-genome duplications and their developmental complexity. For these reasons, amphioxus are frequently used as an outgroup to study vertebrate genome evolution and Evo-Devo. Aside from whole-genome duplications, genes continuously duplicate on a smaller scale. Small-scale duplicated genes can be found in both amphioxus and vertebrate genomes, while only the vertebrate genomes have duplicated genes product of their 2R whole-genome duplications. Here, we explore the history of small-scale gene duplications in the amphioxus lineage and compare it to small- and large-scale gene duplication history in vertebrates. RESULTS We present a study of the European amphioxus (Branchiostoma lanceolatum) gene duplications thanks to a new, high-quality genome reference. We find that, despite its overall slow molecular evolution, the amphioxus lineage has had a history of small-scale duplications similar to the one observed in vertebrates. We find parallel gene duplication profiles between amphioxus and vertebrates and conserved functional constraints in gene duplication. Moreover, amphioxus gene duplicates show levels of expression and patterns of functional specialization similar to the ones observed in vertebrate duplicated genes. We also find strong conservation of gene synteny between two distant amphioxus species, B. lanceolatum and B. floridae, with two major chromosomal rearrangements. CONCLUSIONS In contrast to their slower molecular and morphological evolution, amphioxus' small-scale gene duplication history resembles that of the vertebrate lineage both in quantitative and in functional terms.
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Affiliation(s)
- Marina Brasó-Vives
- grid.9851.50000 0001 2165 4204Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland ,grid.419765.80000 0001 2223 3006Swiss Institute of Bioinformatics (SIB), Lausanne, Switzerland
| | - Ferdinand Marlétaz
- grid.83440.3b0000000121901201Department of Genetics, Evolution and Environment (GEE), University College London, London, UK
| | - Amina Echchiki
- grid.9851.50000 0001 2165 4204Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland ,grid.419765.80000 0001 2223 3006Swiss Institute of Bioinformatics (SIB), Lausanne, Switzerland
| | - Federica Mantica
- grid.11478.3b0000 0004 1766 3695Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Rafael D. Acemel
- grid.15449.3d0000 0001 2200 2355Andalusian Centre for Developmental Biology (CABD), CSIC-Pablo Olavide University, Sevilla, Spain
| | - José L. Gómez-Skarmeta
- grid.15449.3d0000 0001 2200 2355Andalusian Centre for Developmental Biology (CABD), CSIC-Pablo Olavide University, Sevilla, Spain
| | - Diego A. Hartasánchez
- grid.9851.50000 0001 2165 4204Department of Computational Biology, University of Lausanne, Lausanne, Switzerland
| | - Lorlane Le Targa
- IRD, APHM, MEPHI, Aix Marseille Université, Marseille, France ,grid.483853.10000 0004 0519 5986IHU-Méditerranée Infection, Marseille, France
| | - Pierre Pontarotti
- IRD, APHM, MEPHI, Aix Marseille Université, Marseille, France ,grid.483853.10000 0004 0519 5986IHU-Méditerranée Infection, Marseille, France ,grid.4444.00000 0001 2112 9282CNRS, Paris, France
| | - Juan J. Tena
- grid.15449.3d0000 0001 2200 2355Andalusian Centre for Developmental Biology (CABD), CSIC-Pablo Olavide University, Sevilla, Spain
| | - Ignacio Maeso
- grid.15449.3d0000 0001 2200 2355Andalusian Centre for Developmental Biology (CABD), CSIC-Pablo Olavide University, Sevilla, Spain ,grid.5841.80000 0004 1937 0247Department of Genetics, Microbiology and Statistics, University of Barcelona, Barcelona, Spain
| | - Hector Escriva
- grid.462844.80000 0001 2308 1657Biologie Intégrative des Organismes Marins, BIOM, CNRS-Sorbonne University, Banyuls-sur-Mer, France
| | - Manuel Irimia
- grid.11478.3b0000 0004 1766 3695Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology, Barcelona, Spain ,grid.5612.00000 0001 2172 2676Pompeu Fabra University (UPF), Barcelona, Spain ,grid.425902.80000 0000 9601 989XICREA, Barcelona, Spain
| | - Marc Robinson-Rechavi
- grid.9851.50000 0001 2165 4204Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland ,grid.419765.80000 0001 2223 3006Swiss Institute of Bioinformatics (SIB), Lausanne, Switzerland
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4
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Ross CJ, Ulitsky I. Discovering functional motifs in long noncoding RNAs. WILEY INTERDISCIPLINARY REVIEWS. RNA 2022; 13:e1708. [PMID: 34981665 DOI: 10.1002/wrna.1708] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 11/19/2021] [Accepted: 12/04/2021] [Indexed: 12/27/2022]
Abstract
Long noncoding RNAs (lncRNAs) are products of pervasive transcription that closely resemble messenger RNAs on the molecular level, yet function through largely unknown modes of action. The current model is that the function of lncRNAs often relies on specific, typically short, conserved elements, connected by linkers in which specific sequences and/or structures are less important. This notion has fueled the development of both computational and experimental methods focused on the discovery of functional elements within lncRNA genes, based on diverse signals such as evolutionary conservation, predicted structural elements, or the ability to rescue loss-of-function phenotypes. In this review, we outline the main challenges that the different methods need to overcome, describe the recently developed approaches, and discuss their respective limitations. This article is categorized under: RNA Evolution and Genomics > Computational Analyses of RNA RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications Regulatory RNAs/RNAi/Riboswitches > Regulatory RNAs.
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Affiliation(s)
- Caroline Jane Ross
- Biological Regulation and Molecular Neuroscience, Weizmann Institute of Science, Rehovot, Israel
| | - Igor Ulitsky
- Biological Regulation and Molecular Neuroscience, Weizmann Institute of Science, Rehovot, Israel
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5
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Camilleri-Robles C, Amador R, Klein CC, Guigó R, Corominas M, Ruiz-Romero M. Genomic and functional conservation of lncRNAs: lessons from flies. Mamm Genome 2022; 33:328-342. [PMID: 35098341 PMCID: PMC9114055 DOI: 10.1007/s00335-021-09939-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 12/09/2021] [Indexed: 12/18/2022]
Abstract
Over the last decade, the increasing interest in long non-coding RNAs (lncRNAs) has led to the discovery of these transcripts in multiple organisms. LncRNAs tend to be specifically, and often lowly, expressed in certain tissues, cell types and biological contexts. Although lncRNAs participate in the regulation of a wide variety of biological processes, including development and disease, most of their functions and mechanisms of action remain unknown. Poor conservation of the DNA sequences encoding for these transcripts makes the identification of lncRNAs orthologues among different species very challenging, especially between evolutionarily distant species such as flies and humans or mice. However, the functions of lncRNAs are unexpectedly preserved among different species supporting the idea that conservation occurs beyond DNA sequences and reinforcing the potential of characterising lncRNAs in animal models. In this review, we describe the features and roles of lncRNAs in the fruit fly Drosophila melanogaster, focusing on genomic and functional comparisons with human and mouse lncRNAs. We also discuss the current state of advances and limitations in the study of lncRNA conservation and future perspectives.
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6
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Novikova EL, Kulakova MA. There and Back Again: Hox Clusters Use Both DNA Strands. J Dev Biol 2021; 9:28. [PMID: 34287306 PMCID: PMC8293171 DOI: 10.3390/jdb9030028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 07/06/2021] [Accepted: 07/13/2021] [Indexed: 12/25/2022] Open
Abstract
Bilaterian animals operate the clusters of Hox genes through a rich repertoire of diverse mechanisms. In this review, we will summarize and analyze the accumulated data concerning long non-coding RNAs (lncRNAs) that are transcribed from sense (coding) DNA strands of Hox clusters. It was shown that antisense regulatory RNAs control the work of Hox genes in cis and trans, participate in the establishment and maintenance of the epigenetic code of Hox loci, and can even serve as a source of regulatory peptides that switch cellular energetic metabolism. Moreover, these molecules can be considered as a force that consolidates the cluster into a single whole. We will discuss the examples of antisense transcription of Hox genes in well-studied systems (cell cultures, morphogenesis of vertebrates) and bear upon some interesting examples of antisense Hox RNAs in non-model Protostomia.
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Affiliation(s)
- Elena L. Novikova
- Department of Embryology, St. Petersburg State University, Universitetskaya nab. 7–9, 199034 Saint Petersburg, Russia;
- Laboratory of Evolutionary Morphology, Zoological Institute RAS, Universitetskaya nab. 1, 199034 Saint Petersburg, Russia
| | - Milana A. Kulakova
- Department of Embryology, St. Petersburg State University, Universitetskaya nab. 7–9, 199034 Saint Petersburg, Russia;
- Laboratory of Evolutionary Morphology, Zoological Institute RAS, Universitetskaya nab. 1, 199034 Saint Petersburg, Russia
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7
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Comparative genomics in the search for conserved long noncoding RNAs. Essays Biochem 2021; 65:741-749. [PMID: 33885137 PMCID: PMC8564735 DOI: 10.1042/ebc20200069] [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] [Received: 12/18/2020] [Revised: 02/15/2021] [Accepted: 03/15/2021] [Indexed: 12/23/2022]
Abstract
Long noncoding RNAs (lncRNAs) have emerged as prominent regulators of gene expression in eukaryotes. The identification of lncRNA orthologs is essential in efforts to decipher their roles across model organisms, as homologous genes tend to have similar molecular and biological functions. The relatively high sequence plasticity of lncRNA genes compared with protein-coding genes, makes the identification of their orthologs a challenging task. This is why comparative genomics of lncRNAs requires the development of specific and, sometimes, complex approaches. Here, we briefly review current advancements and challenges associated with four levels of lncRNA conservation: genomic sequences, splicing signals, secondary structures and syntenic transcription.
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8
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Analysis of Fox genes in Schmidtea mediterranea reveals new families and a conserved role of Smed-foxO in controlling cell death. Sci Rep 2021; 11:2947. [PMID: 33536473 PMCID: PMC7859237 DOI: 10.1038/s41598-020-80627-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 12/18/2020] [Indexed: 01/30/2023] Open
Abstract
The forkhead box (Fox) genes encode transcription factors that control several key aspects of development. Present in the ancestor of all eukaryotes, Fox genes underwent several duplications followed by loss and diversification events that gave rise to the current 25 families. However, few Fox members have been identified from the Lophotrochozoa clade, and specifically from planarians, which are a unique model for understanding development, due to the striking plasticity of the adult. The aim of this study was to identify and perform evolutionary and functional studies of the Fox genes of lophotrochozoan species and, specifically, of the planarian Schmidtea mediterranea. Generating a pipeline for identifying Forkhead domains and using phylogenetics allowed us the phylogenetic reconstruction of Fox genes. We corrected the annotation for misannotated genes and uncovered a new family, the QD, present in all metazoans. According to the new phylogeny, the 27 Fox genes found in Schmidtea mediterranea were classified into 12 families. In Platyhelminthes, family losses were accompanied by extensive gene diversification and the appearance of specific families, the A(P) and N(P). Among the newly identified planarian Fox genes, we found a single copy of foxO, which shows an evolutionary conserved role in controlling cell death.
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Zawisza-Álvarez M, Pérez-Calles C, Gattoni G, Garcia-Fernàndez J, Benito-Gutiérrez È, Herrera-Úbeda C. The ADAR Family in Amphioxus: RNA Editing and Conserved Orthologous Site Predictions. Genes (Basel) 2020; 11:genes11121440. [PMID: 33265998 PMCID: PMC7761149 DOI: 10.3390/genes11121440] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 11/23/2020] [Accepted: 11/28/2020] [Indexed: 01/21/2023] Open
Abstract
RNA editing is a relatively unexplored process in which transcribed RNA is modified at specific nucleotides before translation, adding another level of regulation of gene expression. Cephalopods use it extensively to increase the regulatory complexity of their nervous systems, and mammals use it too, but less prominently. Nevertheless, little is known about the specifics of RNA editing in most of the other clades and the relevance of RNA editing from an evolutionary perspective remains unknown. Here we analyze a key element of the editing machinery, the ADAR (adenosine deaminase acting on RNA) gene family, in an animal with a key phylogenetic position at the root of chordates: the cephalochordate amphioxus. We show, that as in cephalopods, ADAR genes in amphioxus are predominantly expressed in the nervous system; we identify a number of RNA editing events in amphioxus; and we provide a newly developed method to identify RNA editing events in highly polymorphic genomes using orthology as a guide. Overall, our work lays the foundations for future comparative analysis of RNA-editing events across the metazoan tree.
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Affiliation(s)
- Michał Zawisza-Álvarez
- Department of Genetics, Microbiology and Statistics, Faculty of Biology, and Institut de Biomedicina (IBUB), University of Barcelona, 08007 Barcelona, Spain; (M.Z.-Á.); (C.P.-C.); (J.G.-F.)
| | - Claudia Pérez-Calles
- Department of Genetics, Microbiology and Statistics, Faculty of Biology, and Institut de Biomedicina (IBUB), University of Barcelona, 08007 Barcelona, Spain; (M.Z.-Á.); (C.P.-C.); (J.G.-F.)
- Department of Zoology, University of Cambridge, Cambridge CB2 1TN, UK;
| | - Giacomo Gattoni
- Department of Zoology, University of Cambridge, Cambridge CB2 1TN, UK;
| | - Jordi Garcia-Fernàndez
- Department of Genetics, Microbiology and Statistics, Faculty of Biology, and Institut de Biomedicina (IBUB), University of Barcelona, 08007 Barcelona, Spain; (M.Z.-Á.); (C.P.-C.); (J.G.-F.)
| | - Èlia Benito-Gutiérrez
- Department of Zoology, University of Cambridge, Cambridge CB2 1TN, UK;
- Correspondence: (È.B.-G.); (C.H.-Ú.)
| | - Carlos Herrera-Úbeda
- Department of Genetics, Microbiology and Statistics, Faculty of Biology, and Institut de Biomedicina (IBUB), University of Barcelona, 08007 Barcelona, Spain; (M.Z.-Á.); (C.P.-C.); (J.G.-F.)
- Correspondence: (È.B.-G.); (C.H.-Ú.)
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10
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Maciel LF, Morales-Vicente DA, Verjovski-Almeida S. Dynamic Expression of Long Non-Coding RNAs Throughout Parasite Sexual and Neural Maturation in Schistosoma japonicum. Noncoding RNA 2020; 6:E15. [PMID: 32244675 PMCID: PMC7344908 DOI: 10.3390/ncrna6020015] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 03/19/2020] [Accepted: 03/28/2020] [Indexed: 02/07/2023] Open
Abstract
Schistosoma japonicum is a flatworm that causes schistosomiasis, a neglected tropical disease. S. japonicum RNA-Seq analyses has been previously reported in the literature on females and males obtained during sexual maturation from 14 to 28 days post-infection in mouse, resulting in the identification of protein-coding genes and pathways, whose expression levels were related to sexual development. However, this work did not include an analysis of long non-coding RNAs (lncRNAs). Here, we applied a pipeline to identify and annotate lncRNAs in 66 S. japonicum RNA-Seq publicly available libraries, from different life-cycle stages. We also performed co-expression analyses to find stage-specific lncRNAs possibly related to sexual maturation. We identified 12,291 S. japonicum expressed lncRNAs. Sequence similarity search and synteny conservation indicated that some 14% of S. japonicum intergenic lncRNAs have synteny conservation with S. mansoni intergenic lncRNAs. Co-expression analyses showed that lncRNAs and protein-coding genes in S. japonicum males and females have a dynamic co-expression throughout sexual maturation, showing differential expression between the sexes; the protein-coding genes were related to the nervous system development, lipid and drug metabolism, and overall parasite survival. Co-expression pattern suggests that lncRNAs possibly regulate these processes or are regulated by the same activation program as that of protein-coding genes.
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Affiliation(s)
- Lucas F. Maciel
- Laboratório de Expressão Gênica em Eucariotos, Instituto Butantan, São Paulo SP 05503-900, Brazil (D.A.M.-V.)
- Programa Interunidades em Bioinformática, Instituto de Matemática e Estatística, Universidade de São Paulo, São Paulo SP 05508-900, Brazil
| | - David A. Morales-Vicente
- Laboratório de Expressão Gênica em Eucariotos, Instituto Butantan, São Paulo SP 05503-900, Brazil (D.A.M.-V.)
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo SP 05508-900, Brazil
| | - Sergio Verjovski-Almeida
- Laboratório de Expressão Gênica em Eucariotos, Instituto Butantan, São Paulo SP 05503-900, Brazil (D.A.M.-V.)
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo SP 05508-900, Brazil
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11
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Vakirlis N, Carvunis AR, McLysaght A. Synteny-based analyses indicate that sequence divergence is not the main source of orphan genes. eLife 2020; 9:e53500. [PMID: 32066524 PMCID: PMC7028367 DOI: 10.7554/elife.53500] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 01/07/2020] [Indexed: 12/20/2022] Open
Abstract
The origin of 'orphan' genes, species-specific sequences that lack detectable homologues, has remained mysterious since the dawn of the genomic era. There are two dominant explanations for orphan genes: complete sequence divergence from ancestral genes, such that homologues are not readily detectable; and de novo emergence from ancestral non-genic sequences, such that homologues genuinely do not exist. The relative contribution of the two processes remains unknown. Here, we harness the special circumstance of conserved synteny to estimate the contribution of complete divergence to the pool of orphan genes. By separately comparing yeast, fly and human genes to related taxa using conservative criteria, we find that complete divergence accounts, on average, for at most a third of eukaryotic orphan and taxonomically restricted genes. We observe that complete divergence occurs at a stable rate within a phylum but at different rates between phyla, and is frequently associated with gene shortening akin to pseudogenization.
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Affiliation(s)
- Nikolaos Vakirlis
- Smurfit Institute of GeneticsTrinity College Dublin, University of DublinDublinIreland
| | - Anne-Ruxandra Carvunis
- Department of Computational and Systems Biology, Pittsburgh Center for Evolutionary Biology and Medicine, School of MedicineUniversity of PittsburghPittsburghUnited States
| | - Aoife McLysaght
- Smurfit Institute of GeneticsTrinity College Dublin, University of DublinDublinIreland
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