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Cīrulis A, Nordén AK, Churcher AM, Ramm SA, Zadesenets KS, Abbott JK. Sex-limited experimental evolution drives transcriptomic divergence in a hermaphrodite. Genome Biol Evol 2024; 16:evad235. [PMID: 38155579 PMCID: PMC10786194 DOI: 10.1093/gbe/evad235] [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: 02/22/2023] [Revised: 12/12/2023] [Accepted: 12/23/2023] [Indexed: 12/30/2023] Open
Abstract
The evolution of gonochorism from hermaphroditism is linked with the formation of sex chromosomes, as well as the evolution of sex-biased and sex-specific gene expression to allow both sexes to reach their fitness optimum. There is evidence that sexual selection drives the evolution of male-biased gene expression in particular. However, previous research in this area in animals comes from either theoretical models or comparative studies of already old sex chromosomes. We therefore investigated changes in gene expression under 3 different selection regimes for the simultaneous hermaphrodite Macrostomum lignano subjected to sex-limited experimental evolution (i.e. selection for fitness via eggs, sperm, or a control regime allowing both). After 21 and 22 generations of selection for male-specific or female-specific fitness, we characterized changes in whole-organism gene expression. We found that female-selected lines had changed the most in their gene expression. Although annotation for this species is limited, gene ontology term and Kyoto Encyclopedia of Genes and Genomes pathway analyses suggest that metabolic changes (e.g. biosynthesis of amino acids and carbon metabolism) are an important adaptive component. As predicted, we found that the expression of genes previously identified as testis-biased candidates tended to be downregulated in the female-selected lines. We did not find any significant expression differences for previously identified candidates of other sex-specific organs, but this may simply reflect that few transcripts have been characterized in this way. In conclusion, our experiment suggests that changes in testis-biased gene expression are important in the early evolution of sex chromosomes and gonochorism.
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Affiliation(s)
- Aivars Cīrulis
- Department of Biology, Lund University, 223 62 Lund, Sweden
- Laboratory of Microbiology and Pathology, Institute of Food Safety, Animal Health and Environment “BIOR,”Riga LV-1076, Latvia
- Faculty of Biology, University of Latvia, Riga LV-1004, Latvia
| | - Anna K Nordén
- Department of Biology, Lund University, 223 62 Lund, Sweden
| | - Allison M Churcher
- Department of Molecular Biology, National Bioinformatics Infrastructure Sweden, Umeå University, 901 87 Umeå, Sweden
| | - Steven A Ramm
- Department of Evolutionary Biology, Bielefeld University, 33615 Bielefeld, Germany
- UMR 6553 ECOBIO, Université de Rennes, 35042 Rennes, France
| | - Kira S Zadesenets
- Department of Molecular Genetics, Cell Biology and Bionformatics, The Federal Research Center Institute of Cytology and Genetics SB RAS, 630090 Novosibirsk, Russian Federation
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Kainth AS, Haddad GA, Hall JM, Ruthenburg AJ. Merging short and stranded long reads improves transcript assembly. PLoS Comput Biol 2023; 19:e1011576. [PMID: 37883581 PMCID: PMC10629667 DOI: 10.1371/journal.pcbi.1011576] [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: 12/08/2022] [Revised: 11/07/2023] [Accepted: 10/05/2023] [Indexed: 10/28/2023] Open
Abstract
Long-read RNA sequencing has arisen as a counterpart to short-read sequencing, with the potential to capture full-length isoforms, albeit at the cost of lower depth. Yet this potential is not fully realized due to inherent limitations of current long-read assembly methods and underdeveloped approaches to integrate short-read data. Here, we critically compare the existing methods and develop a new integrative approach to characterize a particularly challenging pool of low-abundance long noncoding RNA (lncRNA) transcripts from short- and long-read sequencing in two distinct cell lines. Our analysis reveals severe limitations in each of the sequencing platforms. For short-read assemblies, coverage declines at transcript termini resulting in ambiguous ends, and uneven low coverage results in segmentation of a single transcript into multiple transcripts. Conversely, long-read sequencing libraries lack depth and strand-of-origin information in cDNA-based methods, culminating in erroneous assembly and quantitation of transcripts. We also discover a cDNA synthesis artifact in long-read datasets that markedly impacts the identity and quantitation of assembled transcripts. Towards remediating these problems, we develop a computational pipeline to "strand" long-read cDNA libraries that rectifies inaccurate mapping and assembly of long-read transcripts. Leveraging the strengths of each platform and our computational stranding, we also present and benchmark a hybrid assembly approach that drastically increases the sensitivity and accuracy of full-length transcript assembly on the correct strand and improves detection of biological features of the transcriptome. When applied to a challenging set of under-annotated and cell-type variable lncRNA, our method resolves the segmentation problem of short-read sequencing and the depth problem of long-read sequencing, resulting in the assembly of coherent transcripts with precise 5' and 3' ends. Our workflow can be applied to existing datasets for superior demarcation of transcript ends and refined isoform structure, which can enable better differential gene expression analyses and molecular manipulations of transcripts.
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Affiliation(s)
- Amoldeep S. Kainth
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, Illinois, United States of America
| | - Gabriela A. Haddad
- Committee on Genetics, Genomics and Systems Biology, The University of Chicago, Chicago, Illinois, United States of America
| | - Johnathon M. Hall
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, Illinois, United States of America
| | - Alexander J. Ruthenburg
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, Illinois, United States of America
- Committee on Genetics, Genomics and Systems Biology, The University of Chicago, Chicago, Illinois, United States of America
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, Illinois, United States of America
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3
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Amaral P, Carbonell-Sala S, De La Vega FM, Faial T, Frankish A, Gingeras T, Guigo R, Harrow JL, Hatzigeorgiou AG, Johnson R, Murphy TD, Pertea M, Pruitt KD, Pujar S, Takahashi H, Ulitsky I, Varabyou A, Wells CA, Yandell M, Carninci P, Salzberg SL. The status of the human gene catalogue. Nature 2023; 622:41-47. [PMID: 37794265 PMCID: PMC10575709 DOI: 10.1038/s41586-023-06490-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Accepted: 07/27/2023] [Indexed: 10/06/2023]
Abstract
Scientists have been trying to identify every gene in the human genome since the initial draft was published in 2001. In the years since, much progress has been made in identifying protein-coding genes, currently estimated to number fewer than 20,000, with an ever-expanding number of distinct protein-coding isoforms. Here we review the status of the human gene catalogue and the efforts to complete it in recent years. Beside the ongoing annotation of protein-coding genes, their isoforms and pseudogenes, the invention of high-throughput RNA sequencing and other technological breakthroughs have led to a rapid growth in the number of reported non-coding RNA genes. For most of these non-coding RNAs, the functional relevance is currently unclear; we look at recent advances that offer paths forward to identifying their functions and towards eventually completing the human gene catalogue. Finally, we examine the need for a universal annotation standard that includes all medically significant genes and maintains their relationships with different reference genomes for the use of the human gene catalogue in clinical settings.
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Affiliation(s)
- Paulo Amaral
- INSPER Institute of Education and Research, Sao Paulo, Brazil
| | | | - Francisco M De La Vega
- Department of Biomedical Data Science, Stanford University School of Medicine, Stanford, CA, USA
- Tempus Labs, Chicago, IL, USA
| | | | - Adam Frankish
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, UK
| | - Thomas Gingeras
- Department of Functional Genomics, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | - Roderic Guigo
- Centre for Genomic Regulation (CRG), Barcelona, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Jennifer L Harrow
- Centre for Genomics Research, Discovery Sciences, AstraZeneca, Royston, UK
| | - Artemis G Hatzigeorgiou
- Department of Computer Science and Biomedical Informatics, Universithy of Thessaly, Lamia, Greece
- Hellenic Pasteur Institute, Athens, Greece
| | - Rory Johnson
- School of Biology and Environmental Science, University College Dublin, Dublin, Ireland
- Conway Institute of Biomedical and Biomolecular Research, University College Dublin, Dublin, Ireland
- Department of Medical Oncology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
- Department for BioMedical Research, University of Bern, Bern, Switzerland
| | - Terence D Murphy
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA
| | - Mihaela Pertea
- Center for Computational Biology, Johns Hopkins University, Baltimore, MD, USA
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
- Department of Computer Science, Johns Hopkins University, Baltimore, MD, USA
| | - Kim D Pruitt
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA
| | - Shashikant Pujar
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA
| | - Hazuki Takahashi
- Laboratory for Transcriptome Technology, RIKEN Center for Integrative Medical Sciences, Yokohama, Japan
| | - Igor Ulitsky
- Department of Immunology and Regenerative Biology, Weizmann Institute of Science, Rehovot, Israel
- Department of Molecular Neuroscience, Weizmann Institute of Science, Rehovot, Israel
| | - Ales Varabyou
- Center for Computational Biology, Johns Hopkins University, Baltimore, MD, USA
- Department of Computer Science, Johns Hopkins University, Baltimore, MD, USA
| | - Christine A Wells
- Stem Cell Systems, Department of Anatomy and Physiology, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Mark Yandell
- Departent of Human Genetics, Utah Center for Genetic Discovery, University of Utah, Salt Lake City, UT, USA
| | - Piero Carninci
- Laboratory for Transcriptome Technology, RIKEN Center for Integrative Medical Sciences, Yokohama, Japan.
- Human Technopole, Milan, Italy.
| | - Steven L Salzberg
- Center for Computational Biology, Johns Hopkins University, Baltimore, MD, USA.
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA.
- Department of Computer Science, Johns Hopkins University, Baltimore, MD, USA.
- Department of Biostatistics, Johns Hopkins University, Baltimore, MD, USA.
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Amaral P, Carbonell-Sala S, De La Vega FM, Faial T, Frankish A, Gingeras T, Guigo R, Harrow JL, Hatzigeorgiou AG, Johnson R, Murphy TD, Pertea M, Pruitt KD, Pujar S, Takahashi H, Ulitsky I, Varabyou A, Wells CA, Yandell M, Carninci P, Salzberg SL. The status of the human gene catalogue. ARXIV 2023:arXiv:2303.13996v1. [PMID: 36994150 PMCID: PMC10055485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Subscribe] [Scholar Register] [Indexed: 03/31/2023]
Abstract
Scientists have been trying to identify all of the genes in the human genome since the initial draft of the genome was published in 2001. Over the intervening years, much progress has been made in identifying protein-coding genes, and the estimated number has shrunk to fewer than 20,000, although the number of distinct protein-coding isoforms has expanded dramatically. The invention of high-throughput RNA sequencing and other technological breakthroughs have led to an explosion in the number of reported non-coding RNA genes, although most of them do not yet have any known function. A combination of recent advances offers a path forward to identifying these functions and towards eventually completing the human gene catalogue. However, much work remains to be done before we have a universal annotation standard that includes all medically significant genes, maintains their relationships with different reference genomes, and describes clinically relevant genetic variants.
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Affiliation(s)
- Paulo Amaral
- INSPER Institute of Education and Research, São Paulo, SP, Brasil
| | - Silvia Carbonell-Sala
- Centre for Genomic Regulation (CRG), Dr. Aiguader 88, 08003, Barcelona, Catalonia, Spain
| | - Francisco M. De La Vega
- Department of Biomedical Data Science, Stanford University School of Medicine, Stanford, CA; Tempus Labs, Inc., Chicago, IL
| | | | - Adam Frankish
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, Cambridge CB10 1SD, UK
| | - Thomas Gingeras
- Department of Functional Genomics, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY
| | - Roderic Guigo
- Centre for Genomic Regulation (CRG), Dr. Aiguader 88, 08003, Barcelona, Catalonia, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Catalonia, Spain
| | - Jennifer L Harrow
- Centre for Genomics Research, Discovery Sciences, AstraZeneca, Da Vinci Building. Melbourn Science Park, Royston UK SG8 6HB
| | - Artemis G. Hatzigeorgiou
- Universithy of Thessaly, Department of Computer Science and Biomedical Informatics, Lamia, Greece; Hellenic Pasteur Institute, Athens, Greece
| | - Rory Johnson
- School of Biology and Environmental Science, University College Dublin, D04 V1W8 Dublin, Ireland; Conway Institute of Biomedical and Biomolecular Research, University College Dublin, D04 V1W8 Dublin, Ireland; Department of Medical Oncology, Inselspital, Bern University Hospital, University of Bern, 3010 Bern, Switzerland; Department for BioMedical Research, University of Bern, 3008 Bern, Switzerland
| | - Terence D. Murphy
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
| | - Mihaela Pertea
- Center for Computational Biology, Johns Hopkins University, Baltimore, MD, USA
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Kim D. Pruitt
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
| | - Shashikant Pujar
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
| | - Hazuki Takahashi
- Laboratory for Transcriptome Technology, RIKEN Center for Integrative Medical Sciences, Yokohama Kanagawa 230-0045 Japan
| | - Igor Ulitsky
- Department of Immunology and Regenerative Biology; Department of Molecular Neuroscience, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Ales Varabyou
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
- Department of Computer Science, Johns Hopkins University, Baltimore, MD, USA
| | - Christine A. Wells
- Stem Cell Systems, Department of Anatomy and Physiology, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville 3010 Vic Australia
| | - Mark Yandell
- Departent of Human Genetics, Utah Center for Genetic Discovery, University of Utah, Salt Lake City, UT, USA
| | - Piero Carninci
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
- Human Technopole, via Rita Levi Montalcini 1, Milan 20157 Italy
| | - Steven L. Salzberg
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
- Center for Computational Biology, Johns Hopkins University, Baltimore, MD, USA
- Department of Immunology and Regenerative Biology; Department of Molecular Neuroscience, Weizmann Institute of Science, Rehovot 76100, Israel
- Department of Biostatistics, Johns Hopkins University, Baltimore, MD, USA
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Flnc: Machine Learning Improves the Identification of Novel Long Noncoding RNAs from Stand-Alone RNA-Seq Data. Noncoding RNA 2022; 8:ncrna8050070. [DOI: 10.3390/ncrna8050070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 10/01/2022] [Accepted: 10/06/2022] [Indexed: 11/16/2022] Open
Abstract
Long noncoding RNAs (lncRNAs) play critical regulatory roles in human development and disease. Although there are over 100,000 samples with available RNA sequencing (RNA-seq) data, many lncRNAs have yet to be annotated. The conventional approach to identifying novel lncRNAs from RNA-seq data is to find transcripts without coding potential but this approach has a false discovery rate of 30–75%. Other existing methods either identify only multi-exon lncRNAs, missing single-exon lncRNAs, or require transcriptional initiation profiling data (such as H3K4me3 ChIP-seq data), which is unavailable for many samples with RNA-seq data. Because of these limitations, current methods cannot accurately identify novel lncRNAs from existing RNA-seq data. To address this problem, we have developed software, Flnc, to accurately identify both novel and annotated full-length lncRNAs, including single-exon lncRNAs, directly from RNA-seq data without requiring transcriptional initiation profiles. Flnc integrates machine learning models built by incorporating four types of features: transcript length, promoter signature, multiple exons, and genomic location. Flnc achieves state-of-the-art prediction power with an AUROC score over 0.92. Flnc significantly improves the prediction accuracy from less than 50% using the conventional approach to over 85%. Flnc is available via GitHub platform.
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