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Brown AL, Meiborg AB, Franz-Wachtel M, Macek B, Gordon S, Rog O, Weadick CJ, Werner MS. Characterization of the Pristionchus pacificus "epigenetic toolkit" reveals the evolutionary loss of the histone methyltransferase complex PRC2. Genetics 2024; 227:iyae041. [PMID: 38513719 DOI: 10.1093/genetics/iyae041] [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: 12/04/2023] [Revised: 12/04/2023] [Accepted: 03/05/2024] [Indexed: 03/23/2024] Open
Abstract
Comparative approaches have revealed both divergent and convergent paths to achieving shared developmental outcomes. Thus, only through assembling multiple case studies can we understand biological principles. Yet, despite appreciating the conservation-or lack thereof-of developmental networks, the conservation of epigenetic mechanisms regulating these networks is poorly understood. The nematode Pristionchus pacificus has emerged as a model system of plasticity and epigenetic regulation as it exhibits a bacterivorous or omnivorous morph depending on its environment. Here, we determined the "epigenetic toolkit" available to P. pacificus as a resource for future functional work on plasticity, and as a comparison with Caenorhabditis elegans to investigate the conservation of epigenetic mechanisms. Broadly, we observed a similar cast of genes with putative epigenetic function between C. elegans and P. pacificus. However, we also found striking differences. Most notably, the histone methyltransferase complex PRC2 appears to be missing in P. pacificus. We described the deletion/pseudogenization of the PRC2 genes mes-2 and mes-6 and concluded that both were lost in the last common ancestor of P. pacificus and a related species P. arcanus. Interestingly, we observed the enzymatic product of PRC2 (H3K27me3) by mass spectrometry and immunofluorescence, suggesting that a currently unknown methyltransferase has been co-opted for heterochromatin silencing. Altogether, we have provided an inventory of epigenetic genes in P. pacificus to compare with C. elegans. This inventory will enable reverse-genetic experiments related to plasticity and has revealed the first loss of PRC2 in a multicellular organism.
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Affiliation(s)
- Audrey L Brown
- School of Biological Sciences, The University of Utah, Salt Lake City, UT 84112, USA
| | - Adriaan B Meiborg
- Developmental Biology Unit, European Molecular Biology Laboratory (EMBL), 69117 Heidelberg, Germany
- Faculty of Biosciences, Collaboration for joint PhD degree between EMBL and Heidelberg University, 69120 Heidelberg, Germany
| | | | - Boris Macek
- Proteome Center Tübingen, University of Tübingen, 72074 Tübingen, Germany
| | - Spencer Gordon
- School of Biological Sciences, The University of Utah, Salt Lake City, UT 84112, USA
| | - Ofer Rog
- School of Biological Sciences, The University of Utah, Salt Lake City, UT 84112, USA
| | | | - Michael S Werner
- School of Biological Sciences, The University of Utah, Salt Lake City, UT 84112, USA
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2
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Dickson ZW, Golding GB. Evolution of Transcript Abundance is Influenced by Indels in Protein Low Complexity Regions. J Mol Evol 2024; 92:153-168. [PMID: 38485789 DOI: 10.1007/s00239-024-10158-z] [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: 10/05/2023] [Accepted: 01/24/2024] [Indexed: 04/02/2024]
Abstract
Protein Protein low complexity regions (LCRs) are compositionally biased amino acid sequences, many of which have significant evolutionary impacts on the proteins which contain them. They are mutationally unstable experiencing higher rates of indels and substitutions than higher complexity regions. LCRs also impact the expression of their proteins, likely through multiple effects along the path from gene transcription, through translation, and eventual protein degradation. It has been observed that proteins which contain LCRs are associated with elevated transcript abundance (TAb), despite having lower protein abundance. We have gathered and integrated human data to investigate the co-evolution of TAb and LCRs through ancestral reconstructions and model inference using an approximate Bayesian calculation based method. We observe that on short evolutionary timescales TAb evolution is significantly impacted by changes in LCR length, with insertions driving TAb down. But in contrast, the observed data is best explained by indel rates in LCRs which are unaffected by shifts in TAb. Our work demonstrates a coupling between LCR and TAb evolution, and the utility of incorporating multiple responses into evolutionary analyses.
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Affiliation(s)
| | - G Brian Golding
- Department of Biology, McMaster University, Hamilton, ON, Canada
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3
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Rödelsperger C. Comparative Genomics of Sex, Chromosomes, and Sex Chromosomes in Caenorhabditis elegans and Other Nematodes. Methods Mol Biol 2024; 2802:455-472. [PMID: 38819568 DOI: 10.1007/978-1-0716-3838-5_15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2024]
Abstract
The nematode phylum has evolved a remarkable diversity of reproductive modes, including the repeated emergence of asexuality and hermaphroditism across divergent clades. The species-richness and small genome size of nematodes make them ideal systems for investigating the genome-wide causes and consequences of such major transitions. The availability of functional annotations for most Caenorhabditis elegans genes further allows the linking of patterns of gene content evolution with biological processes. Such gene-centric studies were recently complemented by investigations of chromosome evolution that made use of the first chromosome-scale genome assemblies outside the Caenorhabditis genus. This review highlights recent comparative genomic studies of reproductive mode evolution addressing the hybrid origin of asexuality and the parallel gene loss following the emergence of hermaphroditism. It further summarizes ongoing efforts to characterize ancient linkage blocks called Nigon elements, which form central units of chromosome evolution. Fusions between Nigon elements have been demonstrated to impact recombination and speciation. Finally, multiple recent fusions between autosomal and the sex-linked Nigon element reveal insights into the dynamic evolution of sex chromosomes across various timescales.
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Affiliation(s)
- Christian Rödelsperger
- Department for Integrative Evolutionary Biology, Max Planck Institute for Biology, Tübingen, Germany.
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4
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Fakhar AZ, Liu J, Pajerowska-Mukhtar KM, Mukhtar MS. The ORFans' tale: new insights in plant biology. TRENDS IN PLANT SCIENCE 2023; 28:1379-1390. [PMID: 37453923 DOI: 10.1016/j.tplants.2023.06.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Revised: 05/17/2023] [Accepted: 06/19/2023] [Indexed: 07/18/2023]
Abstract
Orphan genes (OGs) are protein-coding genes without a significant sequence similarity in closely related species. Despite their functional importance, very little is known about the underlying molecular mechanisms by which OGs participate in diverse biological processes. Here, we discuss the evolutionary mechanisms of OGs' emergence with relevance to species-specific adaptations. We also provide a mechanistic view of the involvement of OGs in multiple processes, including growth, development, reproduction, and carbon-metabolism-mediated immunity. We highlight the interconnection between OGs and the sucrose nonfermenting 1 (SNF1)-related protein kinases (SnRKs)-target of rapamycin (TOR) signaling axis for phytohormone signaling, nutrient metabolism, and stress responses. Finally, we propose a high-throughput pipeline for OGs' interspecies and intraspecies gene transfer through a transgenic approach for future biotechnological advances.
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Affiliation(s)
- Ali Zeeshan Fakhar
- Department of Biology, University of Alabama at Birmingham, 1300 University Blvd., Birmingham, AL 35294, USA
| | - Jinbao Liu
- Department of Biology, University of Alabama at Birmingham, 1300 University Blvd., Birmingham, AL 35294, USA
| | | | - M Shahid Mukhtar
- Department of Biology, University of Alabama at Birmingham, 1300 University Blvd., Birmingham, AL 35294, USA.
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5
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Araujo NDS, Perez R, Willot Q, Defrance M, Aron S. Facing lethal temperatures: Heat-shock response in desert and temperate ants. Ecol Evol 2023; 13:e10438. [PMID: 37720060 PMCID: PMC10500329 DOI: 10.1002/ece3.10438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 08/06/2023] [Accepted: 08/07/2023] [Indexed: 09/19/2023] Open
Abstract
Global climate changes may cause profound effects on species adaptation, particularly in ectotherms for whom even moderate warmer temperatures can lead to disproportionate heat failure. Still, several organisms evolved to endure high desert temperatures. Here, we describe the thermal tolerance survival and the transcriptomic heat stress response of three genera of desert (Cataglyphis, Melophorus, and Ocymyrmex) and two of temperate ants (Formica and Myrmica) and explore convergent and specific adaptations. We found heat stress led to either a reactive or a constitutive response in desert ants: Cataglyphis holgerseni and Melophorus bagoti differentially regulated very few transcripts in response to heat (0.12% and 0.14%, respectively), while Cataglyphis bombycina and Ocymyrmex robustior responded with greater expression alterations (respectively affecting 0.6% and 1.53% of their transcriptomes). These two responsive mechanisms-reactive and constitutive-were related to individual thermal tolerance survival and convergently evolved in distinct desert ant genera. Moreover, in comparison with desert species, the two temperate ants differentially expressed thousands of transcripts more in response to heat stress (affecting 8% and 12.71% of F. fusca and Myr. sabuleti transcriptomes). In summary, we show that heat adaptation in thermophilic ants involved changes in the expression response. Overall, desert ants show reduced transcriptional alterations even when under high thermal stress, and their expression response may be either constitutive or reactive to temperature increase.
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Affiliation(s)
| | - Rémy Perez
- Department of Evolutionary Biology & EcologyUniversité Libre de BruxellesBrusselsBelgium
| | - Quentin Willot
- Department of Evolutionary Biology & EcologyUniversité Libre de BruxellesBrusselsBelgium
- Zoophysiology, Department of BiologyAarhus UniversityAarhus‐CDenmark
| | - Matthieu Defrance
- Interuniversity Institute of Bioinformatics in BrusselsUniversité Libre de BruxellesBrusselsBelgium
| | - Serge Aron
- Department of Evolutionary Biology & EcologyUniversité Libre de BruxellesBrusselsBelgium
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6
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Catalán A, Merondun J, Knief U, Wolf JBW. Chromatin accessibility, not 5mC methylation covaries with partial dosage compensation in crows. PLoS Genet 2023; 19:e1010901. [PMID: 37747941 PMCID: PMC10575545 DOI: 10.1371/journal.pgen.1010901] [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: 03/16/2023] [Revised: 10/13/2023] [Accepted: 08/07/2023] [Indexed: 09/27/2023] Open
Abstract
The evolution of genetic sex determination is often accompanied by degradation of the sex-limited chromosome. Male heterogametic systems have evolved convergent, epigenetic mechanisms restoring the resulting imbalance in gene dosage between diploid autosomes (AA) and the hemizygous sex chromosome (X). Female heterogametic systems (AAf Zf, AAm ZZm) tend to only show partial dosage compensation (0.5 < Zf:AAf < 1) and dosage balance (0.5
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Affiliation(s)
- Ana Catalán
- Department of Evolutionary Biology, Evolutionary Biology Centre (EBC), Uppsala University, Uppsala, Sweden
- Division of Evolutionary Biology, LMU Munich, Planegg-Martinsried, Germany
| | - Justin Merondun
- Division of Evolutionary Biology, LMU Munich, Planegg-Martinsried, Germany
| | - Ulrich Knief
- Division of Evolutionary Biology, LMU Munich, Planegg-Martinsried, Germany
- Evolutionary Biology & Ecology,Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Jochen B. W. Wolf
- Department of Evolutionary Biology, Evolutionary Biology Centre (EBC), Uppsala University, Uppsala, Sweden
- Division of Evolutionary Biology, LMU Munich, Planegg-Martinsried, Germany
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7
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Werner MS, Loschko T, King T, Reich S, Theska T, Franz-Wachtel M, Macek B, Sommer RJ. Histone 4 lysine 5/12 acetylation enables developmental plasticity of Pristionchus mouth form. Nat Commun 2023; 14:2095. [PMID: 37055396 PMCID: PMC10102330 DOI: 10.1038/s41467-023-37734-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Accepted: 03/28/2023] [Indexed: 04/15/2023] Open
Abstract
Development can be altered to match phenotypes with the environment, and the genetic mechanisms that direct such alternative phenotypes are beginning to be elucidated. Yet, the rules that govern environmental sensitivity vs. invariant development, and potential epigenetic memory, remain unknown. Here, we show that plasticity of nematode mouth forms is determined by histone 4 lysine 5 and 12 acetylation (H4K5/12ac). Acetylation in early larval stages provides a permissive chromatin state, which is susceptible to induction during the critical window of environmental sensitivity. As development proceeds deacetylation shuts off switch gene expression to end the critical period. Inhibiting deacetylase enzymes leads to fixation of prior developmental trajectories, demonstrating that histone modifications in juveniles can carry environmental information to adults. Finally, we provide evidence that this regulation was derived from an ancient mechanism of licensing developmental speed. Altogether, our results show that H4K5/12ac enables epigenetic regulation of developmental plasticity that can be stored and erased by acetylation and deacetylation, respectively.
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Affiliation(s)
- Michael S Werner
- Department for Integrative Evolutionary Biology, Max Planck Institute for Biology Tübingen, Tübingen, 72076, Germany
- School of Biological Sciences, The University of Utah, Salt Lake City, UT, USA
| | - Tobias Loschko
- Department for Integrative Evolutionary Biology, Max Planck Institute for Biology Tübingen, Tübingen, 72076, Germany
| | - Thomas King
- School of Biological Sciences, The University of Utah, Salt Lake City, UT, USA
| | - Shelley Reich
- School of Biological Sciences, The University of Utah, Salt Lake City, UT, USA
| | - Tobias Theska
- Department for Integrative Evolutionary Biology, Max Planck Institute for Biology Tübingen, Tübingen, 72076, Germany
| | | | - Boris Macek
- Proteome Center Tübingen, University of Tübingen, Tübingen, 72076, Germany
| | - Ralf J Sommer
- Department for Integrative Evolutionary Biology, Max Planck Institute for Biology Tübingen, Tübingen, 72076, Germany.
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8
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Yoshida K, Rödelsperger C, Röseler W, Riebesell M, Sun S, Kikuchi T, Sommer RJ. Chromosome fusions repatterned recombination rate and facilitated reproductive isolation during Pristionchus nematode speciation. Nat Ecol Evol 2023; 7:424-439. [PMID: 36717742 PMCID: PMC9998273 DOI: 10.1038/s41559-022-01980-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2022] [Accepted: 12/29/2022] [Indexed: 02/01/2023]
Abstract
Large-scale genome-structural evolution is common in various organisms. Recent developments in speciation genomics revealed the importance of inversions, whereas the role of other genome-structural rearrangements, including chromosome fusions, have not been well characterized. We study genomic divergence and reproductive isolation of closely related nematodes: the androdioecious (hermaphroditic) model Pristionchus pacificus and its dioecious sister species Pristionchus exspectatus. A chromosome-level genome assembly of P. exspectatus using single-molecule and Hi-C sequencing revealed a chromosome-wide rearrangement relative to P. pacificus. Strikingly, genomic characterization and cytogenetic studies including outgroup species Pristionchus occultus indicated two independent fusions involving the same chromosome, ChrIR, between these related species. Genetic linkage analysis indicated that these fusions altered the chromosome-wide pattern of recombination, resulting in large low-recombination regions that probably facilitated the coevolution between some of the ~14.8% of genes across the entire genomes. Quantitative trait locus analyses for hybrid sterility in all three sexes revealed that major quantitative trait loci mapped to the fused chromosome ChrIR. While abnormal chromosome segregations of the fused chromosome partially explain hybrid female sterility, hybrid-specific recombination that breaks linkage of genes in the low-recombination region was associated with hybrid male sterility. Thus, recent chromosome fusions repatterned recombination rate and drove reproductive isolation during Pristionchus speciation.
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Affiliation(s)
- Kohta Yoshida
- Department for Integrative Evolutionary Biology, Max Planck Institute for Biology, Tübingen, Germany.
| | - Christian Rödelsperger
- Department for Integrative Evolutionary Biology, Max Planck Institute for Biology, Tübingen, Germany
| | - Waltraud Röseler
- Department for Integrative Evolutionary Biology, Max Planck Institute for Biology, Tübingen, Germany
| | - Metta Riebesell
- Department for Integrative Evolutionary Biology, Max Planck Institute for Biology, Tübingen, Germany
| | - Simo Sun
- Faculty of Medicine, University of Miyazaki, Miyazaki, Japan
| | - Taisei Kikuchi
- Faculty of Medicine, University of Miyazaki, Miyazaki, Japan
| | - Ralf J Sommer
- Department for Integrative Evolutionary Biology, Max Planck Institute for Biology, Tübingen, Germany.
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9
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Lenuzzi M, Witte H, Riebesell M, Rödelsperger C, Hong RL, Sommer RJ. Influence of environmental temperature on mouth-form plasticity in Pristionchus pacificus acts through daf-11-dependent cGMP signaling. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART B, MOLECULAR AND DEVELOPMENTAL EVOLUTION 2023; 340:214-224. [PMID: 34379868 DOI: 10.1002/jez.b.23094] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 07/14/2021] [Accepted: 07/30/2021] [Indexed: 12/16/2022]
Abstract
Mouth-form plasticity in the nematode Pristionchus pacificus has become a powerful system to identify the genetic and molecular mechanisms associated with developmental (phenotypic) plasticity. In particular, the identification of developmental switch genes that can sense environmental stimuli and reprogram developmental processes has confirmed long-standing evolutionary theory. However, how these genes are involved in the direct sensing of the environment, or if the switch genes act downstream of another, primary environmental sensing mechanism, remains currently unknown. Here, we study the influence of environmental temperature on mouth-form plasticity. We find that environmental temperature does influence mouth-form plasticity in most of the 10 wild isolates of P. pacificus tested in this study. We used one of these strains, P. pacificus RSA635, for detailed molecular analysis. Using forward and reverse genetic technology including CRISPR/Cas9, we show that mutations in the guanylyl cyclase Ppa-daf-11, the Ppa-daf-25/AnkMy2, and the cyclic nucleotide-gated channel Ppa-tax-2 eliminate the response to elevated temperatures. Together, our study indicates that DAF-11, DAF-25, and TAX-2 have been co-opted for environmental sensing during mouth-form plasticity regulation in P. pacificus.
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Affiliation(s)
- Maša Lenuzzi
- Department for Integrative Evolutionary Biology, Max-Planck Institute for Developmental Biology, Tübingen, Germany
| | - Hanh Witte
- Department for Integrative Evolutionary Biology, Max-Planck Institute for Developmental Biology, Tübingen, Germany
| | - Metta Riebesell
- Department for Integrative Evolutionary Biology, Max-Planck Institute for Developmental Biology, Tübingen, Germany
| | - Christian Rödelsperger
- Department for Integrative Evolutionary Biology, Max-Planck Institute for Developmental Biology, Tübingen, Germany
| | - Ray L Hong
- Department of Biology, California State University, Northridge, California, USA
| | - Ralf J Sommer
- Department for Integrative Evolutionary Biology, Max-Planck Institute for Developmental Biology, Tübingen, Germany
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10
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Chen Y, Ma T, Zhang T, Ma L. Trends in the evolution of intronless genes in Poaceae. FRONTIERS IN PLANT SCIENCE 2023; 14:1065631. [PMID: 36875616 PMCID: PMC9978806 DOI: 10.3389/fpls.2023.1065631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Accepted: 02/01/2023] [Indexed: 06/18/2023]
Abstract
Intronless genes (IGs), which are a feature of prokaryotes, are a fascinating group of genes that are also present in eukaryotes. In the current study, a comparison of Poaceae genomes revealed that the origin of IGs may have involved ancient intronic splicing, reverse transcription, and retrotranspositions. Additionally, IGs exhibit the typical features of rapid evolution, including recent duplications, variable copy numbers, low divergence between paralogs, and high non-synonymous to synonymous substitution ratios. By tracing IG families along the phylogenetic tree, we determined that the evolutionary dynamics of IGs differed among Poaceae subfamilies. IG families developed rapidly before the divergence of Pooideae and Oryzoideae and expanded slowly after the divergence. In contrast, they emerged gradually and consistently in the Chloridoideae and Panicoideae clades during evolution. Furthermore, IGs are expressed at low levels. Under relaxed selection pressure, retrotranspositions, intron loss, and gene duplications and conversions may promote the evolution of IGs. The comprehensive characterization of IGs is critical for in-depth studies on intron functions and evolution as well as for assessing the importance of introns in eukaryotes.
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Affiliation(s)
- Yong Chen
- *Correspondence: Tingting Zhang, ; Lei Ma,
| | | | | | - Lei Ma
- *Correspondence: Tingting Zhang, ; Lei Ma,
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11
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Chitin contributes to the formation of a feeding structure in a predatory nematode. Curr Biol 2023; 33:15-27.e6. [PMID: 36460010 DOI: 10.1016/j.cub.2022.11.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 09/20/2022] [Accepted: 11/04/2022] [Indexed: 12/03/2022]
Abstract
Some nematode predators and parasites form teeth-like denticles that are histologically different from vertebrate teeth, but their biochemical composition remains elusive. Here, we show a role of chitin in the formation of teeth-like denticles in Pristionchus pacificus, a model system for studying predation and feeding structure plasticity. Pristionchus forms two alternative mouth morphs with one tooth or two teeth, respectively. The P. pacificus genome encodes two chitin synthases, with the highly conserved chs-2 gene being composed of 60 exons forming at least four isoforms. Generating CRISPR-Cas9-based gene knockouts, we found that Ppa-chs-2 mutations that eliminate the chitin-synthase domain are lethal. However, mutations in the C terminus result in viable but teethless worms, with severe malformation of the mouth. Similarly, treatment with the chitin-synthase inhibitor Nikkomycin Z also results in teethless animals. Teethless worms can feed on various bacterial food sources but are incapable of predation. High-resolution transcriptomics revealed that Ppa-chs-2 expression is controlled by the sulfatase-encoding developmental switch Ppa-eud-1. This study indicates a key role of chitin in the formation of teeth-like denticles and the complex feeding apparatus in nematodes.
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12
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Raxwal VK, Singh S, Agarwal M, Riha K. Transcriptional and post-transcriptional regulation of young genes in plants. BMC Biol 2022; 20:134. [PMID: 35676681 PMCID: PMC9178820 DOI: 10.1186/s12915-022-01339-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 05/30/2022] [Indexed: 12/03/2022] Open
Abstract
Background New genes continuously emerge from non-coding DNA or by diverging from existing genes, but most of them are rapidly lost and only a few become fixed within the population. We hypothesized that young genes are subject to transcriptional and post-transcriptional regulation to limit their expression and minimize their exposure to purifying selection. Results We performed a protein-based homology search across the tree of life to determine the evolutionary age of protein-coding genes present in the rice genome. We found that young genes in rice have relatively low expression levels, which can be attributed to distal enhancers, and closed chromatin conformation at their transcription start sites (TSS). The chromatin in TSS regions can be re-modeled in response to abiotic stress, indicating conditional expression of young genes. Furthermore, transcripts of young genes in Arabidopsis tend to be targeted by nonsense-mediated RNA decay, presenting another layer of regulation limiting their expression. Conclusions These data suggest that transcriptional and post-transcriptional mechanisms contribute to the conditional expression of young genes, which may alleviate purging selection while providing an opportunity for phenotypic exposure and functionalization. Supplementary Information The online version contains supplementary material available at 10.1186/s12915-022-01339-7.
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Affiliation(s)
- Vivek Kumar Raxwal
- Department of Botany, University of Delhi, Delhi, 110007, India. .,Central European Institute of Technology (CEITEC), Masaryk University, Brno, Czech Republic.
| | - Somya Singh
- Department of Botany, University of Delhi, Delhi, 110007, India
| | - Manu Agarwal
- Department of Botany, University of Delhi, Delhi, 110007, India.
| | - Karel Riha
- Central European Institute of Technology (CEITEC), Masaryk University, Brno, Czech Republic.
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13
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Gueno J, Borg M, Bourdareau S, Cossard G, Godfroy O, Lipinska A, Tirichine L, Cock J, Coelho S. Chromatin landscape associated with sexual differentiation in a UV sex determination system. Nucleic Acids Res 2022; 50:3307-3322. [PMID: 35253891 PMCID: PMC8989524 DOI: 10.1093/nar/gkac145] [Citation(s) in RCA: 1] [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: 05/06/2021] [Revised: 02/15/2022] [Accepted: 03/04/2022] [Indexed: 12/12/2022] Open
Abstract
In many eukaryotes, such as dioicous mosses and many algae, sex is determined by UV sex chromosomes and is expressed during the haploid phase of the life cycle. In these species, the male and female developmental programs are initiated by the presence of the U- or V-specific regions of the sex chromosomes but, as in XY and ZW systems, sexual differentiation is largely driven by autosomal sex-biased gene expression. The mechanisms underlying the regulation of sex-biased expression of genes during sexual differentiation remain elusive. Here, we investigated the extent and nature of epigenomic changes associated with UV sexual differentiation in the brown alga Ectocarpus, a model UV system. Six histone modifications were quantified in near-isogenic lines, leading to the identification of 16 chromatin signatures across the genome. Chromatin signatures correlated with levels of gene expression and histone PTMs changes in males versus females occurred preferentially at genes involved in sex-specific pathways. Despite the absence of chromosome scale dosage compensation and the fact that UV sex chromosomes recombine across most of their length, the chromatin landscape of these chromosomes was remarkably different to that of autosomes. Hotspots of evolutionary young genes in the pseudoautosomal regions appear to drive the exceptional chromatin features of UV sex chromosomes.
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Affiliation(s)
- Josselin Gueno
- Sorbonne Université, UPMC Univ Paris 06, CNRS, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, F-29688 Roscoff, France
| | - Michael Borg
- Department of Algal Development and Evolution, Max Planck Institute for Biology Tübingen72076, Tübingen, Germany
| | - Simon Bourdareau
- Sorbonne Université, UPMC Univ Paris 06, CNRS, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, F-29688 Roscoff, France
| | - Guillaume Cossard
- Sorbonne Université, UPMC Univ Paris 06, CNRS, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, F-29688 Roscoff, France
| | - Olivier Godfroy
- Sorbonne Université, UPMC Univ Paris 06, CNRS, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, F-29688 Roscoff, France
| | - Agnieszka Lipinska
- Sorbonne Université, UPMC Univ Paris 06, CNRS, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, F-29688 Roscoff, France
- Department of Algal Development and Evolution, Max Planck Institute for Biology Tübingen72076, Tübingen, Germany
| | - Leila Tirichine
- Nantes Universite, CNRS, US2B, UMR 6286, F-44000, Nantes, France
| | - J Mark Cock
- Sorbonne Université, UPMC Univ Paris 06, CNRS, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, F-29688 Roscoff, France
| | - Susana M Coelho
- Sorbonne Université, UPMC Univ Paris 06, CNRS, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, F-29688 Roscoff, France
- Department of Algal Development and Evolution, Max Planck Institute for Biology Tübingen72076, Tübingen, Germany
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14
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Abstract
The nematode Caenorhabditis elegans has shed light on many aspects of eukaryotic biology, including genetics, development, cell biology, and genomics. A major factor in the success of C. elegans as a model organism has been the availability, since the late 1990s, of an essentially gap-free and well-annotated nuclear genome sequence, divided among 6 chromosomes. In this review, we discuss the structure, function, and biology of C. elegans chromosomes and then provide a general perspective on chromosome biology in other diverse nematode species. We highlight malleable chromosome features including centromeres, telomeres, and repetitive elements, as well as the remarkable process of programmed DNA elimination (historically described as chromatin diminution) that induces loss of portions of the genome in somatic cells of a handful of nematode species. An exciting future prospect is that nematode species may enable experimental approaches to study chromosome features and to test models of chromosome evolution. In the long term, fundamental insights regarding how speciation is integrated with chromosome biology may be revealed.
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Affiliation(s)
- Peter M Carlton
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8501, Japan
| | - Richard E Davis
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Denver, CO 80045, USA.,RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Shawn Ahmed
- Department of Genetics, University of North Carolina, Chapel Hill, NC 27599, USA.,Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA
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15
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Lo WS, Sommer RJ. Vitamin B 12 and predatory behavior in nematodes. VITAMINS AND HORMONES 2022; 119:471-489. [PMID: 35337632 DOI: 10.1016/bs.vh.2022.01.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The round worms or nematodes are the largest phylum of animals with an estimated species number of more than one million. Nematodes have invaded all ecosystems and are known from all continents including Antarctica. Parasitic species infest plants, animals and humans often with high host-specificity. Free-living species are known from marine, fresh water and soil systems, the latter of which contain many culturable species. This includes Caenorhabditis elegans, a species that was developed as one of the most prominent model systems in modern biology since the 1960ies. Pristionchus pacificus is a second nematode model organism that can easily be cultured in the laboratory. This species shows a number of complex traits including omnivorous feeding and the capability of predation on other nematodes. Predation depends on the formation of teeth-like denticles in the mouth of P. pacificus, structures unknown from C. elegans and most other nematodes. Here, we review the current knowledge about the role of vitamin B12 for the predatory behavior in P. pacificus and correlate its role with that on the physiology and development in C. elegans.
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Affiliation(s)
- Wen-Sui Lo
- Max Planck Institute for Biology Tübingen, Tübingen, Germany
| | - Ralf J Sommer
- Max Planck Institute for Biology Tübingen, Tübingen, Germany.
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16
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Cherezov RO, Vorontsova JE, Simonova OB. The Phenomenon of Evolutionary “De Novo Generation” of Genes. Russ J Dev Biol 2021. [DOI: 10.1134/s1062360421060035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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17
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Yates TB, Feng K, Zhang J, Singan V, Jawdy SS, Ranjan P, Abraham PE, Barry K, Lipzen A, Pan C, Schmutz J, Chen JG, Tuskan GA, Muchero W. The Ancient Salicoid Genome Duplication Event: A Platform for Reconstruction of De Novo Gene Evolution in Populus trichocarpa. Genome Biol Evol 2021; 13:evab198. [PMID: 34469536 PMCID: PMC8445398 DOI: 10.1093/gbe/evab198] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/22/2021] [Indexed: 12/13/2022] Open
Abstract
Orphan genes are characteristic genomic features that have no detectable homology to genes in any other species and represent an important attribute of genome evolution as sources of novel genetic functions. Here, we identified 445 genes specific to Populus trichocarpa. Of these, we performed deeper reconstruction of 13 orphan genes to provide evidence of de novo gene evolution. Populus and its sister genera Salix are particularly well suited for the study of orphan gene evolution because of the Salicoid whole-genome duplication event which resulted in highly syntenic sister chromosomal segments across the Salicaceae. We leveraged this genomic feature to reconstruct de novo gene evolution from intergenera, interspecies, and intragenomic perspectives by comparing the syntenic regions within the P. trichocarpa reference, then P. deltoides, and finally Salix purpurea. Furthermore, we demonstrated that 86.5% of the putative orphan genes had evidence of transcription. Additionally, we also utilized the Populus genome-wide association mapping panel, a collection of 1,084 undomesticated P. trichocarpa genotypes to further determine putative regulatory networks of orphan genes using expression quantitative trait loci (eQTL) mapping. Functional enrichment of these eQTL subnetworks identified common biological themes associated with orphan genes such as response to stress and defense response. We also identify a putative cis-element for a de novo gene and leverage conserved synteny to describe evolution of a putative transcription factor binding site. Overall, 45% of orphan genes were captured in trans-eQTL networks.
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Affiliation(s)
- Timothy B Yates
- Bredesen Center for Interdisciplinary Research, University of Tennessee, Knoxville, Tennessee, USA
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
- Center for Bioenergy Innovation, Oak Ridge, Tennessee, USA
| | - Kai Feng
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
- Center for Bioenergy Innovation, Oak Ridge, Tennessee, USA
| | - Jin Zhang
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
- Center for Bioenergy Innovation, Oak Ridge, Tennessee, USA
| | - Vasanth Singan
- U.S. Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Sara S Jawdy
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
- Center for Bioenergy Innovation, Oak Ridge, Tennessee, USA
| | - Priya Ranjan
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
- Center for Bioenergy Innovation, Oak Ridge, Tennessee, USA
| | - Paul E Abraham
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
- Center for Bioenergy Innovation, Oak Ridge, Tennessee, USA
| | - Kerrie Barry
- U.S. Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Anna Lipzen
- U.S. Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Chongle Pan
- School of Computer Science and Department of Microbiology and Plant Biology, University of Oklahoma, Norman, Oklahoma, USA
| | - Jeremy Schmutz
- U.S. Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, California, USA
- HudsonAlpha Institute for Biotechnology, Huntsville, Alabama, USA
| | - Jin-Gui Chen
- Bredesen Center for Interdisciplinary Research, University of Tennessee, Knoxville, Tennessee, USA
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
- Center for Bioenergy Innovation, Oak Ridge, Tennessee, USA
| | - Gerald A Tuskan
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
- Center for Bioenergy Innovation, Oak Ridge, Tennessee, USA
| | - Wellington Muchero
- Bredesen Center for Interdisciplinary Research, University of Tennessee, Knoxville, Tennessee, USA
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
- Center for Bioenergy Innovation, Oak Ridge, Tennessee, USA
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18
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Rillo-Bohn R, Adilardi R, Mitros T, Avşaroğlu B, Stevens L, Köhler S, Bayes J, Wang C, Lin S, Baskevitch KA, Rokhsar DS, Dernburg AF. Analysis of meiosis in Pristionchus pacificus reveals plasticity in homolog pairing and synapsis in the nematode lineage. eLife 2021; 10:70990. [PMID: 34427184 PMCID: PMC8455136 DOI: 10.7554/elife.70990] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 08/23/2021] [Indexed: 11/25/2022] Open
Abstract
Meiosis is conserved across eukaryotes yet varies in the details of its execution. Here we describe a new comparative model system for molecular analysis of meiosis, the nematode Pristionchus pacificus, a distant relative of the widely studied model organism Caenorhabditis elegans. P. pacificus shares many anatomical and other features that facilitate analysis of meiosis in C. elegans. However, while C. elegans has lost the meiosis-specific recombinase Dmc1 and evolved a recombination-independent mechanism to synapse its chromosomes, P. pacificus expresses both DMC-1 and RAD-51. We find that SPO-11 and DMC-1 are required for stable homolog pairing, synapsis, and crossover formation, while RAD-51 is dispensable for these key meiotic processes. RAD-51 and DMC-1 localize sequentially to chromosomes during meiotic prophase and show nonoverlapping functions. We also present a new genetic map for P. pacificus that reveals a crossover landscape very similar to that of C. elegans, despite marked divergence in the regulation of synapsis and crossing-over between these lineages.
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Affiliation(s)
- Regina Rillo-Bohn
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,Howard Hughes Medical Institute, Chevy Chase, United States
| | - Renzo Adilardi
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,Howard Hughes Medical Institute, Chevy Chase, United States
| | - Therese Mitros
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Barış Avşaroğlu
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,Howard Hughes Medical Institute, Chevy Chase, United States
| | - Lewis Stevens
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,Darwin Tree of Life Project, Wellcome Sanger Institute, Cambridge, United Kingdom
| | - Simone Köhler
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,Howard Hughes Medical Institute, Chevy Chase, United States
| | - Joshua Bayes
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Clara Wang
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,Howard Hughes Medical Institute, Chevy Chase, United States
| | - Sabrina Lin
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,Howard Hughes Medical Institute, Chevy Chase, United States
| | - K Alienor Baskevitch
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,Howard Hughes Medical Institute, Chevy Chase, United States
| | - Daniel S Rokhsar
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,Department of Energy Joint Genome Institute, Berkeley, United States.,Okinawa Institute of Science and Technology Graduate University, Onna, Japan.,Chan Zuckerberg Biohub, San Francisco, United States
| | - Abby F Dernburg
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,Howard Hughes Medical Institute, Chevy Chase, United States.,Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, United States.,California Institute for Quantitative Biosciences, Berkeley, United States
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19
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Li J, Singh U, Arendsee Z, Wurtele ES. Landscape of the Dark Transcriptome Revealed Through Re-mining Massive RNA-Seq Data. Front Genet 2021; 12:722981. [PMID: 34484307 PMCID: PMC8415361 DOI: 10.3389/fgene.2021.722981] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 07/26/2021] [Indexed: 12/13/2022] Open
Abstract
The "dark transcriptome" can be considered the multitude of sequences that are transcribed but not annotated as genes. We evaluated expression of 6,692 annotated genes and 29,354 unannotated open reading frames (ORFs) in the Saccharomyces cerevisiae genome across diverse environmental, genetic and developmental conditions (3,457 RNA-Seq samples). Over 30% of the highly transcribed ORFs have translation evidence. Phylostratigraphic analysis infers most of these transcribed ORFs would encode species-specific proteins ("orphan-ORFs"); hundreds have mean expression comparable to annotated genes. These data reveal unannotated ORFs most likely to be protein-coding genes. We partitioned a co-expression matrix by Markov Chain Clustering; the resultant clusters contain 2,468 orphan-ORFs. We provide the aggregated RNA-Seq yeast data with extensive metadata as a project in MetaOmGraph (MOG), a tool designed for interactive analysis and visualization. This approach enables reuse of public RNA-Seq data for exploratory discovery, providing a rich context for experimentalists to make novel, experimentally testable hypotheses about candidate genes.
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Affiliation(s)
- Jing Li
- Genetics and Genomics Graduate Program, Iowa State University, Ames, IA, United States
- Department of Genetics, Development, and Cell Biology, Iowa State University, Ames, IA, United States
- Center for Metabolic Biology, Iowa State University, Ames, IA, United States
| | - Urminder Singh
- Department of Genetics, Development, and Cell Biology, Iowa State University, Ames, IA, United States
- Center for Metabolic Biology, Iowa State University, Ames, IA, United States
- Bioinformatics and Computational Biology Program, Iowa State University, Ames, IA, United States
| | - Zebulun Arendsee
- Department of Genetics, Development, and Cell Biology, Iowa State University, Ames, IA, United States
- Center for Metabolic Biology, Iowa State University, Ames, IA, United States
- Bioinformatics and Computational Biology Program, Iowa State University, Ames, IA, United States
| | - Eve Syrkin Wurtele
- Genetics and Genomics Graduate Program, Iowa State University, Ames, IA, United States
- Department of Genetics, Development, and Cell Biology, Iowa State University, Ames, IA, United States
- Center for Metabolic Biology, Iowa State University, Ames, IA, United States
- Bioinformatics and Computational Biology Program, Iowa State University, Ames, IA, United States
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20
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Sun S, Roedelsperger C, Sommer RJ. Single worm transcriptomics identifies a developmental core network of oscillating genes with deep conservation across nematodes. Genome Res 2021; 31:1590-1601. [PMID: 34301622 PMCID: PMC8415380 DOI: 10.1101/gr.275303.121] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 07/14/2021] [Indexed: 12/05/2022]
Abstract
High-resolution spatial and temporal maps of gene expression have facilitated a comprehensive understanding of animal development and evolution. In nematodes, the small body size represented a major challenge for such studies, but recent advancements have helped overcome this limitation. Here, we have implemented single worm transcriptomics (SWT) in the nematode model organism Pristionchus pacificus to provide a high-resolution map of the developmental transcriptome. We selected 38 time points from hatching of the J2 larvae to young adults to perform transcriptome analysis over 60 h of postembryonic development. A mean sequencing depth of 4.5 million read pairs allowed the detection of more than 23,135 (80%) of all genes. Nearly 3000 (10%) genes showed oscillatory expression with discrete expression levels, phases, and amplitudes. Gene age analysis revealed an overrepresentation of ancient gene classes among oscillating genes, and around one-third of them have 1:1 orthologs in C. elegans. One important gene family overrepresented among oscillating genes is collagens. Several of these collagen genes are regulated by the developmental switch gene eud-1, indicating a potential function in the regulation of mouth-form plasticity, a key developmental process in this facultative predatory nematode. Together, our analysis provides (1) an updated protocol for SWT in nematodes that is applicable to many microscopic species, (2) a 1- to 2-h high-resolution catalog of P. pacificus gene expression throughout postembryonic development, and (3) a comparative analysis of oscillatory gene expression between the two model organisms P. pacificus and C. elegans and associated evolutionary dynamics.
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Affiliation(s)
- Shuai Sun
- Max Planck Institute for Developmental Biology
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21
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Hata T, Satoh S, Takada N, Matsuo M, Obokata J. Kozak Sequence Acts as a Negative Regulator for De Novo Transcription Initiation of Newborn Coding Sequences in the Plant Genome. Mol Biol Evol 2021; 38:2791-2803. [PMID: 33705557 PMCID: PMC8233501 DOI: 10.1093/molbev/msab069] [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] [Indexed: 12/23/2022] Open
Abstract
The manner in which newborn coding sequences and their transcriptional competency emerge during the process of gene evolution remains unclear. Here, we experimentally simulated eukaryotic gene origination processes by mimicking horizontal gene transfer events in the plant genome. We mapped the precise position of the transcription start sites (TSSs) of hundreds of newly introduced promoterless firefly luciferase (LUC) coding sequences in the genome of Arabidopsis thaliana cultured cells. The systematic characterization of the LUC-TSSs revealed that 80% of them occurred under the influence of endogenous promoters, while the remainder underwent de novo activation in the intergenic regions, starting from pyrimidine-purine dinucleotides. These de novo TSSs obeyed unexpected rules; they predominantly occurred ∼100 bp upstream of the LUC inserts and did not overlap with Kozak-containing putative open reading frames (ORFs). These features were the output of the immediate responses to the sequence insertions, rather than a bias in the screening of the LUC gene function. Regarding the wild-type genic TSSs, they appeared to have evolved to lack any ORFs in their vicinities. Therefore, the repulsion by the de novo TSSs of Kozak-containing ORFs described above might be the first selection gate for the occurrence and evolution of TSSs in the plant genome. Based on these results, we characterized the de novo type of TSS identified in the plant genome and discuss its significance in genome evolution.
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Affiliation(s)
- Takayuki Hata
- Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Sakyo-ku, Kyoto, Kyoto, Japan
- Faculty of Agriculture, Setsunan University, Hirakata, Osaka, Japan
| | - Soichirou Satoh
- Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Sakyo-ku, Kyoto, Kyoto, Japan
| | - Naoto Takada
- Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Sakyo-ku, Kyoto, Kyoto, Japan
| | - Mitsuhiro Matsuo
- Faculty of Agriculture, Setsunan University, Hirakata, Osaka, Japan
| | - Junichi Obokata
- Faculty of Agriculture, Setsunan University, Hirakata, Osaka, Japan
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22
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Rödelsperger C, Ebbing A, Sharma DR, Okumura M, Sommer RJ, Korswagen HC. Spatial Transcriptomics of Nematodes Identifies Sperm Cells as a Source of Genomic Novelty and Rapid Evolution. Mol Biol Evol 2021; 38:229-243. [PMID: 32785688 PMCID: PMC8480184 DOI: 10.1093/molbev/msaa207] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Divergence of gene function and expression during development can give rise to phenotypic differences at the level of cells, tissues, organs, and ultimately whole organisms. To gain insights into the evolution of gene expression and novel genes at spatial resolution, we compared the spatially resolved transcriptomes of two distantly related nematodes, Caenorhabditis elegans and Pristionchus pacificus, that diverged 60–90 Ma. The spatial transcriptomes of adult worms show little evidence for strong conservation at the level of single genes. Instead, regional expression is largely driven by recent duplication and emergence of novel genes. Estimation of gene ages across anatomical structures revealed an enrichment of novel genes in sperm-related regions. This provides first evidence in nematodes for the “out of testis” hypothesis that has been previously postulated based on studies in Drosophila and mammals. “Out of testis” genes represent a mix of products of pervasive transcription as well as fast evolving members of ancient gene families. Strikingly, numerous novel genes have known functions during meiosis in Caenorhabditis elegans indicating that even universal processes such as meiosis may be targets of rapid evolution. Our study highlights the importance of novel genes in generating phenotypic diversity and explicitly characterizes gene origination in sperm-related regions. Furthermore, it proposes new functions for previously uncharacterized genes and establishes the spatial transcriptome of Pristionchus pacificus as a catalog for future studies on the evolution of gene expression and function.
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Affiliation(s)
- Christian Rödelsperger
- Department for Integrative Evolutionary Biology, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Annabel Ebbing
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences and University Medical Center Utrecht, Utrecht, The Netherlands
| | - Devansh Raj Sharma
- Department for Integrative Evolutionary Biology, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Misako Okumura
- Program of Biomedical Science, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, Hiroshima, Japan
| | - Ralf J Sommer
- Department for Integrative Evolutionary Biology, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Hendrik C Korswagen
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences and University Medical Center Utrecht, Utrecht, The Netherlands.,Developmental Biology, Department of Biology, Institute of Biodynamics and Biocomplexity, Utrecht University, Utrecht, The Netherlands
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23
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Hata T, Takada N, Hayakawa C, Kazama M, Uchikoba T, Tachikawa M, Matsuo M, Satoh S, Obokata J. De novo activated transcription of inserted foreign coding sequences is inheritable in the plant genome. PLoS One 2021; 16:e0252674. [PMID: 34111139 PMCID: PMC8191969 DOI: 10.1371/journal.pone.0252674] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 05/19/2021] [Indexed: 01/16/2023] Open
Abstract
The manner in which inserted foreign coding sequences become transcriptionally activated and fixed in the plant genome is poorly understood. To examine such processes of gene evolution, we performed an artificial evolutionary experiment in Arabidopsis thaliana. As a model of gene-birth events, we introduced a promoterless coding sequence of the firefly luciferase (LUC) gene and established 386 T2-generation transgenic lines. Among them, we determined the individual LUC insertion loci in 76 lines and found that one-third of them were transcribed de novo even in the intergenic or inherently unexpressed regions. In the transcribed lines, transcription-related chromatin marks were detected across the newly activated transcribed regions. These results agreed with our previous findings in A. thaliana cultured cells under a similar experimental scheme. A comparison of the results of the T2-plant and cultured cell experiments revealed that the de novo-activated transcription concomitant with local chromatin remodelling was inheritable. During one-generation inheritance, it seems likely that the transcription activities of the LUC inserts trapped by the endogenous genes/transcripts became stronger, while those of de novo transcription in the intergenic/untranscribed regions became weaker. These findings may offer a clue for the elucidation of the mechanism by which inserted foreign coding sequences become transcriptionally activated and fixed in the plant genome.
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Affiliation(s)
- Takayuki Hata
- Graduate School of Life and Environfmental Sciences, Kyoto Prefectural University, Kyoto-shi, Kyoto, Japan
- Faculty of Agriculture, Setsunan University, Hirakata-shi, Osaka, Japan
| | - Naoto Takada
- Graduate School of Life and Environfmental Sciences, Kyoto Prefectural University, Kyoto-shi, Kyoto, Japan
| | - Chihiro Hayakawa
- Graduate School of Life and Environfmental Sciences, Kyoto Prefectural University, Kyoto-shi, Kyoto, Japan
| | - Mei Kazama
- Graduate School of Life and Environfmental Sciences, Kyoto Prefectural University, Kyoto-shi, Kyoto, Japan
| | - Tomohiro Uchikoba
- Faculty of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto-shi, Kyoto, Japan
| | - Makoto Tachikawa
- Graduate School of Life and Environfmental Sciences, Kyoto Prefectural University, Kyoto-shi, Kyoto, Japan
| | - Mitsuhiro Matsuo
- Faculty of Agriculture, Setsunan University, Hirakata-shi, Osaka, Japan
| | - Soichirou Satoh
- Graduate School of Life and Environfmental Sciences, Kyoto Prefectural University, Kyoto-shi, Kyoto, Japan
- Faculty of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto-shi, Kyoto, Japan
| | - Junichi Obokata
- Faculty of Agriculture, Setsunan University, Hirakata-shi, Osaka, Japan
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24
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Carstensen HR, Villalon RM, Banerjee N, Hallem EA, Hong RL. Steroid hormone pathways coordinate developmental diapause and olfactory remodeling in Pristionchus pacificus. Genetics 2021; 218:6272519. [PMID: 33963848 DOI: 10.1093/genetics/iyab071] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 04/26/2021] [Indexed: 12/31/2022] Open
Abstract
Developmental and behavioral plasticity allow animals to prioritize alternative genetic programs during fluctuating environments. Behavioral remodeling may be acute in animals that interact with host organisms, since reproductive adults and the developmentally arrested larvae often have different ethological needs for chemical stimuli. To understand the genes that coordinate the development and host-seeking behavior, we used the entomophilic nematode Pristionchus pacificus to characterize dauer-constitutive mutants (Daf-c) that inappropriately enter developmental diapause to become dauer larvae. We found two Daf-c loci with dauer-constitutive and cuticle exsheathment phenotypes that can be rescued by the feeding of Δ7-dafachronic acid, and that are dependent on the conserved canonical steroid hormone receptor Ppa-DAF-12. Specifically at one locus, deletions in the sole hydroxysteroid dehydrogenase (HSD) in P. pacificus resulted in Daf-c phenotypes. Ppa-hsd-2 is expressed in the canal-associated neurons (CANs) and excretory cells whose homologous cells in Caenorhabditis elegans are not known to be involved in the dauer decision. While in wildtype only dauer larvae are attracted to host odors, hsd-2 mutant adults show enhanced attraction to the host beetle pheromone, along with ectopic activation of a marker for putative olfactory neurons, Ppa-odr-3. Surprisingly, this enhanced odor attraction acts independently of the Δ7-DA/DAF-12 module, suggesting that Ppa-HSD-2 may be responsible for several steroid hormone products involved in coordinating the dauer decision and host-seeking behavior in P. pacificus.
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Affiliation(s)
- Heather R Carstensen
- Department of Biology, California State University, Northridge, Northridge, CA 91330-8303, USA
| | - Reinard M Villalon
- Department of Biology, California State University, Northridge, Northridge, CA 91330-8303, USA
| | - Navonil Banerjee
- Department of Microbiology, Immunology & Molecular Genetics and Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Elissa A Hallem
- Department of Microbiology, Immunology & Molecular Genetics and Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Ray L Hong
- Department of Biology, California State University, Northridge, Northridge, CA 91330-8303, USA
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25
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Fernández R, Marcet-Houben M, Legeai F, Richard G, Robin S, Wucher V, Pegueroles C, Gabaldón T, Tagu D. Selection following Gene Duplication Shapes Recent Genome Evolution in the Pea Aphid Acyrthosiphon pisum. Mol Biol Evol 2021; 37:2601-2615. [PMID: 32359152 PMCID: PMC7475028 DOI: 10.1093/molbev/msaa110] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Ecology of insects is as wide as their diversity, which reflects their high capacity of adaptation in most of the environments of our planet. Aphids, with over 4,000 species, have developed a series of adaptations including a high phenotypic plasticity and the ability to feed on the phloem sap of plants, which is enriched in sugars derived from photosynthesis. Recent analyses of aphid genomes have indicated a high level of shared ancestral gene duplications that might represent a basis for genetic innovation and broad adaptations. In addition, there are a large number of recent, species-specific gene duplications whose role in adaptation remains poorly understood. Here, we tested whether duplicates specific to the pea aphid Acyrthosiphon pisum are related to genomic innovation by combining comparative genomics, transcriptomics, and chromatin accessibility analyses. Consistent with large levels of neofunctionalization, we found that most of the recent pairs of gene duplicates evolved asymmetrically, showing divergent patterns of positive selection and gene expression. Genes under selection involved a plethora of biological functions, suggesting that neofunctionalization and tissue specificity, among other evolutionary mechanisms, have orchestrated the evolution of recent paralogs in the pea aphid and may have facilitated host-symbiont cooperation. Our comprehensive phylogenomics analysis allowed us to tackle the history of duplicated genes to pave the road toward understanding the role of gene duplication in ecological adaptation.
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Affiliation(s)
- Rosa Fernández
- Centre for Genomic Regulation (CRG), The Barcelona Institute for Science and Technology, Barcelona, Spain.,Animal Biodiversity and Evolution, Institute of Evolutionary Biology (CSIC-UPF), Barcelona, Spain
| | - Marina Marcet-Houben
- Centre for Genomic Regulation (CRG), The Barcelona Institute for Science and Technology, Barcelona, Spain.,Institute for Research in Biomedicine (IRB Barcelona), Barcelona, Spain.,Department of Life Sciences, Barcelona Supercomputing Center, Barcelona, Spain
| | - Fabrice Legeai
- IGEPP, INRAE, Agrocampus Ouest, Université de Rennes 1, Le Rheu, France.,INRIA, IRISA, Genscale, Campus Beaulieu, Rennes, France
| | - Gautier Richard
- IGEPP, INRAE, Agrocampus Ouest, Université de Rennes 1, Le Rheu, France.,Max Planck Institute of Immunobiology and Epigenetics, Freiburg im Breisgau, Germany
| | - Stéphanie Robin
- IGEPP, INRAE, Agrocampus Ouest, Université de Rennes 1, Le Rheu, France.,INRIA, IRISA, GenOuest Core Facility, Campus Beaulieu, Rennes, France
| | - Valentin Wucher
- Centre for Genomic Regulation (CRG), The Barcelona Institute for Science and Technology, Barcelona, Spain
| | - Cinta Pegueroles
- Centre for Genomic Regulation (CRG), The Barcelona Institute for Science and Technology, Barcelona, Spain.,Institute for Research in Biomedicine (IRB Barcelona), Barcelona, Spain.,Department of Life Sciences, Barcelona Supercomputing Center, Barcelona, Spain
| | - Toni Gabaldón
- Centre for Genomic Regulation (CRG), The Barcelona Institute for Science and Technology, Barcelona, Spain.,Institute for Research in Biomedicine (IRB Barcelona), Barcelona, Spain.,Universitat Pompeu Fabra, Barcelona, Spain.,Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain.,Department of Life Sciences, Barcelona Supercomputing Center, Barcelona, Spain
| | - Denis Tagu
- IGEPP, INRAE, Agrocampus Ouest, Université de Rennes 1, Le Rheu, France
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26
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Majic P, Payne JL. Enhancers Facilitate the Birth of De Novo Genes and Gene Integration into Regulatory Networks. Mol Biol Evol 2021; 37:1165-1178. [PMID: 31845961 PMCID: PMC7086177 DOI: 10.1093/molbev/msz300] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Regulatory networks control the spatiotemporal gene expression patterns that give rise to and define the individual cell types of multicellular organisms. In eumetazoa, distal regulatory elements called enhancers play a key role in determining the structure of such networks, particularly the wiring diagram of “who regulates whom.” Mutations that affect enhancer activity can therefore rewire regulatory networks, potentially causing adaptive changes in gene expression. Here, we use whole-tissue and single-cell transcriptomic and chromatin accessibility data from mouse to show that enhancers play an additional role in the evolution of regulatory networks: They facilitate network growth by creating transcriptionally active regions of open chromatin that are conducive to de novo gene evolution. Specifically, our comparative transcriptomic analysis with three other mammalian species shows that young, mouse-specific intergenic open reading frames are preferentially located near enhancers, whereas older open reading frames are not. Mouse-specific intergenic open reading frames that are proximal to enhancers are more highly and stably transcribed than those that are not proximal to enhancers or promoters, and they are transcribed in a limited diversity of cellular contexts. Furthermore, we report several instances of mouse-specific intergenic open reading frames proximal to promoters showing evidence of being repurposed enhancers. We also show that open reading frames gradually acquire interactions with enhancers over macroevolutionary timescales, helping integrate genes—those that have arisen de novo or by other means—into existing regulatory networks. Taken together, our results highlight a dual role of enhancers in expanding and rewiring gene regulatory networks.
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Affiliation(s)
- Paco Majic
- Institute of Integrative Biology, ETH Zurich, Zurich, Switzerland
- Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Joshua L Payne
- Institute of Integrative Biology, ETH Zurich, Zurich, Switzerland
- Swiss Institute of Bioinformatics, Lausanne, Switzerland
- Corresponding author: E-mail:
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27
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Uncovering de novo gene birth in yeast using deep transcriptomics. Nat Commun 2021; 12:604. [PMID: 33504782 PMCID: PMC7841160 DOI: 10.1038/s41467-021-20911-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 01/04/2021] [Indexed: 01/30/2023] Open
Abstract
De novo gene origination has been recently established as an important mechanism for the formation of new genes. In organisms with a large genome, intergenic and intronic regions provide plenty of raw material for new transcriptional events to occur, but little is know about how de novo transcripts originate in more densely-packed genomes. Here, we identify 213 de novo originated transcripts in Saccharomyces cerevisiae using deep transcriptomics and genomic synteny information from multiple yeast species grown in two different conditions. We find that about half of the de novo transcripts are expressed from regions which already harbor other genes in the opposite orientation; these transcripts show similar expression changes in response to stress as their overlapping counterparts, and some appear to translate small proteins. Thus, a large fraction of de novo genes in yeast are likely to co-evolve with already existing genes.
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28
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Athanasouli M, Witte H, Weiler C, Loschko T, Eberhardt G, Sommer RJ, Rödelsperger C. Comparative genomics and community curation further improve gene annotations in the nematode Pristionchus pacificus. BMC Genomics 2020; 21:708. [PMID: 33045985 PMCID: PMC7552371 DOI: 10.1186/s12864-020-07100-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 09/23/2020] [Indexed: 02/07/2023] Open
Abstract
Background Nematode model organisms such as Caenorhabditis elegans and Pristionchus pacificus are powerful systems for studying the evolution of gene function at a mechanistic level. However, the identification of P. pacificus orthologs of candidate genes known from C. elegans is complicated by the discrepancy in the quality of gene annotations, a common problem in nematode and invertebrate genomics. Results Here, we combine comparative genomic screens for suspicious gene models with community-based curation to further improve the quality of gene annotations in P. pacificus. We extend previous curations of one-to-one orthologs to larger gene families and also orphan genes. Cross-species comparisons of protein lengths, screens for atypical domain combinations and species-specific orphan genes resulted in 4311 candidate genes that were subject to community-based curation. Corrections for 2946 gene models were implemented in a new version of the P. pacificus gene annotations. The new set of gene annotations contains 28,896 genes and has a single copy ortholog completeness level of 97.6%. Conclusions Our work demonstrates the effectiveness of comparative genomic screens to identify suspicious gene models and the scalability of community-based approaches to improve the quality of thousands of gene models. Similar community-based approaches can help to improve the quality of gene annotations in other invertebrate species, including parasitic nematodes.
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Affiliation(s)
- Marina Athanasouli
- Department for Integrative Evolutionary Biology, Max Planck Institute for Developmental Biology, Max-Planck-Ring 9, 72076, Tübingen, Germany
| | - Hanh Witte
- Department for Integrative Evolutionary Biology, Max Planck Institute for Developmental Biology, Max-Planck-Ring 9, 72076, Tübingen, Germany
| | - Christian Weiler
- Department for Integrative Evolutionary Biology, Max Planck Institute for Developmental Biology, Max-Planck-Ring 9, 72076, Tübingen, Germany
| | - Tobias Loschko
- Department for Integrative Evolutionary Biology, Max Planck Institute for Developmental Biology, Max-Planck-Ring 9, 72076, Tübingen, Germany
| | - Gabi Eberhardt
- Department for Integrative Evolutionary Biology, Max Planck Institute for Developmental Biology, Max-Planck-Ring 9, 72076, Tübingen, Germany
| | - Ralf J Sommer
- Department for Integrative Evolutionary Biology, Max Planck Institute for Developmental Biology, Max-Planck-Ring 9, 72076, Tübingen, Germany
| | - Christian Rödelsperger
- Department for Integrative Evolutionary Biology, Max Planck Institute for Developmental Biology, Max-Planck-Ring 9, 72076, Tübingen, Germany.
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29
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Dong C, Weadick CJ, Truffault V, Sommer RJ. Convergent evolution of small molecule pheromones in Pristionchus nematodes. eLife 2020; 9:55687. [PMID: 32338597 PMCID: PMC7224695 DOI: 10.7554/elife.55687] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 04/24/2020] [Indexed: 01/05/2023] Open
Abstract
The small molecules that mediate chemical communication between nematodes-so-called 'nematode-derived-modular-metabolites' (NDMMs)-are of major interest because of their ability to regulate development, behavior, and life-history. Pristionchus pacificus nematodes produce an impressive diversity of structurally complex NDMMs, some of which act as primer pheromones that are capable of triggering irreversible developmental switches. Many of these NDMMs have only ever been found in P. pacificus but no attempts have been made to study their evolution by profiling closely related species. This study brings a comparative perspective to the biochemical study of NDMMs through the systematic MS/MS- and NMR-based analysis of exo-metabolomes from over 30 Pristionchus species. We identified 36 novel compounds and found evidence for the convergent evolution of complex NDMMs in separate branches of the Pristionchus phylogeny. Our results demonstrate that biochemical innovation is a recurrent process in Pristionchus nematodes, a pattern that is probably typical across the animal kingdom.
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Affiliation(s)
- Chuanfu Dong
- Department for Integrative Evolutionary Biology, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Cameron J Weadick
- Department of Biosciences, University of Exeter, Exeter, United Kingdom
| | | | - Ralf J Sommer
- Department for Integrative Evolutionary Biology, Max Planck Institute for Developmental Biology, Tübingen, Germany
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30
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Pascual-Carreras E, Marin-Barba M, Herrera-Úbeda C, Font-Martín D, Eckelt K, de Sousa N, García-Fernández J, Saló E, Adell T. Planarian cell number depends on blitzschnell, a novel gene family that balances cell proliferation and cell death. Development 2020; 147:dev.184044. [PMID: 32122990 DOI: 10.1242/dev.184044] [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: 08/20/2019] [Accepted: 02/19/2020] [Indexed: 01/14/2023]
Abstract
Control of cell number is crucial to define body size during animal development and to restrict tumoral transformation. The cell number is determined by the balance between cell proliferation and cell death. Although many genes are known to regulate those processes, the molecular mechanisms underlying the relationship between cell number and body size remain poorly understood. This relationship can be better understood by studying planarians, flatworms that continuously change their body size according to nutrient availability. We identified a novel gene family, blitzschnell (bls), that consists of de novo and taxonomically restricted genes that control cell proliferation:cell death ratio. Their silencing promotes faster regeneration and increases cell number during homeostasis. Importantly, this increase in cell number leads to an increase in body size only in a nutrient-rich environment; in starved planarians, silencing results in a decrease in cell size and cell accumulation that ultimately produces overgrowths. bls expression is downregulated after feeding and is related to activity of the insulin/Akt/mTOR network, suggesting that the bls family evolved in planarians as an additional mechanism for restricting cell number in nutrient-fluctuating environments.
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Affiliation(s)
- Eudald Pascual-Carreras
- Department of Genetics, Microbiology and Statistics and Institute of Biomedicine, Universitat de Barcelona, Barcelona 08028, Catalunya, Spain.,Institut de Biomedicina de la Universitat de Barcelona (IBUB), Universitat de Barcelona, Barcelona 08028, Catalunya, Spain
| | - Marta Marin-Barba
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK
| | - Carlos Herrera-Úbeda
- Department of Genetics, Microbiology and Statistics and Institute of Biomedicine, Universitat de Barcelona, Barcelona 08028, Catalunya, Spain.,Institut de Biomedicina de la Universitat de Barcelona (IBUB), Universitat de Barcelona, Barcelona 08028, Catalunya, Spain
| | - Daniel Font-Martín
- Department of Genetics, Microbiology and Statistics and Institute of Biomedicine, Universitat de Barcelona, Barcelona 08028, Catalunya, Spain.,Institut de Biomedicina de la Universitat de Barcelona (IBUB), Universitat de Barcelona, Barcelona 08028, Catalunya, Spain
| | - Kay Eckelt
- Department of Genetics, Microbiology and Statistics and Institute of Biomedicine, Universitat de Barcelona, Barcelona 08028, Catalunya, Spain.,Institut de Biomedicina de la Universitat de Barcelona (IBUB), Universitat de Barcelona, Barcelona 08028, Catalunya, Spain
| | - Nidia de Sousa
- Department of Genetics, Microbiology and Statistics and Institute of Biomedicine, Universitat de Barcelona, Barcelona 08028, Catalunya, Spain.,Institut de Biomedicina de la Universitat de Barcelona (IBUB), Universitat de Barcelona, Barcelona 08028, Catalunya, Spain
| | - Jordi García-Fernández
- Department of Genetics, Microbiology and Statistics and Institute of Biomedicine, Universitat de Barcelona, Barcelona 08028, Catalunya, Spain.,Institut de Biomedicina de la Universitat de Barcelona (IBUB), Universitat de Barcelona, Barcelona 08028, Catalunya, Spain
| | - Emili Saló
- Department of Genetics, Microbiology and Statistics and Institute of Biomedicine, Universitat de Barcelona, Barcelona 08028, Catalunya, Spain.,Institut de Biomedicina de la Universitat de Barcelona (IBUB), Universitat de Barcelona, Barcelona 08028, Catalunya, Spain
| | - Teresa Adell
- Department of Genetics, Microbiology and Statistics and Institute of Biomedicine, Universitat de Barcelona, Barcelona 08028, Catalunya, Spain .,Institut de Biomedicina de la Universitat de Barcelona (IBUB), Universitat de Barcelona, Barcelona 08028, Catalunya, Spain
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31
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Sieriebriennikov B, Sun S, Lightfoot JW, Witte H, Moreno E, Rödelsperger C, Sommer RJ. Conserved nuclear hormone receptors controlling a novel plastic trait target fast-evolving genes expressed in a single cell. PLoS Genet 2020; 16:e1008687. [PMID: 32282814 PMCID: PMC7179942 DOI: 10.1371/journal.pgen.1008687] [Citation(s) in RCA: 36] [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: 12/11/2019] [Revised: 04/23/2020] [Accepted: 02/20/2020] [Indexed: 12/17/2022] Open
Abstract
Environment shapes development through a phenomenon called developmental plasticity. Deciphering its genetic basis has potential to shed light on the origin of novel traits and adaptation to environmental change. However, molecular studies are scarce, and little is known about molecular mechanisms associated with plasticity. We investigated the gene regulatory network controlling predatory vs. non-predatory dimorphism in the nematode Pristionchus pacificus and found that it consists of genes of extremely different age classes. We isolated mutants in the conserved nuclear hormone receptor nhr-1 with previously unseen phenotypic effects. They disrupt mouth-form determination and result in animals combining features of both wild-type morphs. In contrast, mutants in another conserved nuclear hormone receptor nhr-40 display altered morph ratios, but no intermediate morphology. Despite divergent modes of control, NHR-1 and NHR-40 share transcriptional targets, which encode extracellular proteins that have no orthologs in Caenorhabditis elegans and result from lineage-specific expansions. An array of transcriptional reporters revealed co-expression of all tested targets in the same pharyngeal gland cell. Major morphological changes in this gland cell accompanied the evolution of teeth and predation, linking rapid gene turnover with morphological innovations. Thus, the origin of feeding plasticity involved novelty at the level of genes, cells and behavior.
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Affiliation(s)
- Bogdan Sieriebriennikov
- Department for Integrative Evolutionary Biology, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Shuai Sun
- Department for Integrative Evolutionary Biology, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - James W. Lightfoot
- Department for Integrative Evolutionary Biology, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Hanh Witte
- Department for Integrative Evolutionary Biology, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Eduardo Moreno
- Department for Integrative Evolutionary Biology, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Christian Rödelsperger
- Department for Integrative Evolutionary Biology, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Ralf J. Sommer
- Department for Integrative Evolutionary Biology, Max Planck Institute for Developmental Biology, Tübingen, Germany
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32
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Lindblad KA, Pathmanathan JS, Moreira S, Bracht JR, Sebra RP, Hutton ER, Landweber LF. Capture of complete ciliate chromosomes in single sequencing reads reveals widespread chromosome isoforms. BMC Genomics 2019; 20:1037. [PMID: 31888453 PMCID: PMC6937825 DOI: 10.1186/s12864-019-6189-9] [Citation(s) in RCA: 5] [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: 07/11/2019] [Accepted: 10/15/2019] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Whole-genome shotgun sequencing, which stitches together millions of short sequencing reads into a single genome, ushered in the era of modern genomics and led to a rapid expansion of the number of genome sequences available. Nevertheless, assembly of short reads remains difficult, resulting in fragmented genome sequences. Ultimately, only a sequencing technology capable of capturing complete chromosomes in a single run could resolve all ambiguities. Even "third generation" sequencing technologies produce reads far shorter than most eukaryotic chromosomes. However, the ciliate Oxytricha trifallax has a somatic genome with thousands of chromosomes averaging only 3.2 kbp, making it an ideal candidate for exploring the benefits of sequencing whole chromosomes without assembly. RESULTS We used single-molecule real-time sequencing to capture thousands of complete chromosomes in single reads and to update the published Oxytricha trifallax JRB310 genome assembly. In this version, over 50% of the completed chromosomes with two telomeres derive from single reads. The improved assembly includes over 12,000 new chromosome isoforms, and demonstrates that somatic chromosomes derive from variable rearrangements between somatic segments encoded up to 191,000 base pairs away. However, while long reads reduce the need for assembly, a hybrid approach that supplements long-read sequencing with short reads for error correction produced the most complete and accurate assembly, overall. CONCLUSIONS This assembly provides the first example of complete eukaryotic chromosomes captured by single sequencing reads and demonstrates that traditional approaches to genome assembly can mask considerable structural variation.
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Affiliation(s)
- Kelsi A. Lindblad
- Departments of Biochemistry & Molecular Biophysics and Biological Sciences, Columbia University, New York, NY 10032 USA
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544 USA
| | - Jananan S. Pathmanathan
- Departments of Biochemistry & Molecular Biophysics and Biological Sciences, Columbia University, New York, NY 10032 USA
| | - Sandrine Moreira
- Departments of Biochemistry & Molecular Biophysics and Biological Sciences, Columbia University, New York, NY 10032 USA
| | - John R. Bracht
- Department of Biology, American University, 4400 Massachusetts Avenue, NW, Washington, DC 20016 USA
| | - Robert P. Sebra
- Icahn Institute and Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029 USA
| | - Elizabeth R. Hutton
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544 USA
- Watson School of Biological Sciences, One Bungtown Road, Cold Spring Harbor,, NY 11724 USA
| | - Laura F. Landweber
- Departments of Biochemistry & Molecular Biophysics and Biological Sciences, Columbia University, New York, NY 10032 USA
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33
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Rödelsperger C, Athanasouli M, Lenuzzi M, Theska T, Sun S, Dardiry M, Wighard S, Hu W, Sharma DR, Han Z. Crowdsourcing and the feasibility of manual gene annotation: A pilot study in the nematode Pristionchus pacificus. Sci Rep 2019; 9:18789. [PMID: 31827189 PMCID: PMC6906410 DOI: 10.1038/s41598-019-55359-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Accepted: 11/20/2019] [Indexed: 01/15/2023] Open
Abstract
Nematodes such as Caenorhabditis elegans are powerful systems to study basically all aspects of biology. Their species richness together with tremendous genetic knowledge from C. elegans facilitate the evolutionary study of biological functions using reverse genetics. However, the ability to identify orthologs of candidate genes in other species can be hampered by erroneous gene annotations. To improve gene annotation in the nematode model organism Pristionchus pacificus, we performed a genome-wide screen for C. elegans genes with potentially incorrectly annotated P. pacificus orthologs. We initiated a community-based project to manually inspect more than two thousand candidate loci and to propose new gene models based on recently generated Iso-seq and RNA-seq data. In most cases, misannotation of C. elegans orthologs was due to artificially fused gene predictions and completely missing gene models. The community-based curation raised the gene count from 25,517 to 28,036 and increased the single copy ortholog completeness level from 86% to 97%. This pilot study demonstrates how even small-scale crowdsourcing can drastically improve gene annotations. In future, similar approaches can be used for other species, gene sets, and even larger communities thus making manual annotation of large parts of the genome feasible.
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Affiliation(s)
- Christian Rödelsperger
- Max Planck Institute for Developmental Biology, Department for Integrative Evolutionary Biology, Max-Planck-Ring 9, 72076, Tübingen, Germany.
| | - Marina Athanasouli
- Max Planck Institute for Developmental Biology, Department for Integrative Evolutionary Biology, Max-Planck-Ring 9, 72076, Tübingen, Germany
| | - Maša Lenuzzi
- Max Planck Institute for Developmental Biology, Department for Integrative Evolutionary Biology, Max-Planck-Ring 9, 72076, Tübingen, Germany
| | - Tobias Theska
- Max Planck Institute for Developmental Biology, Department for Integrative Evolutionary Biology, Max-Planck-Ring 9, 72076, Tübingen, Germany
| | - Shuai Sun
- Max Planck Institute for Developmental Biology, Department for Integrative Evolutionary Biology, Max-Planck-Ring 9, 72076, Tübingen, Germany
| | - Mohannad Dardiry
- Max Planck Institute for Developmental Biology, Department for Integrative Evolutionary Biology, Max-Planck-Ring 9, 72076, Tübingen, Germany
| | - Sara Wighard
- Max Planck Institute for Developmental Biology, Department for Integrative Evolutionary Biology, Max-Planck-Ring 9, 72076, Tübingen, Germany
| | - Wen Hu
- Max Planck Institute for Developmental Biology, Department for Integrative Evolutionary Biology, Max-Planck-Ring 9, 72076, Tübingen, Germany
| | - Devansh Raj Sharma
- Max Planck Institute for Developmental Biology, Department for Integrative Evolutionary Biology, Max-Planck-Ring 9, 72076, Tübingen, Germany
| | - Ziduan Han
- Max Planck Institute for Developmental Biology, Department for Integrative Evolutionary Biology, Max-Planck-Ring 9, 72076, Tübingen, Germany
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34
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Rödelsperger C, Prabh N, Sommer RJ. New Gene Origin and Deep Taxon Phylogenomics: Opportunities and Challenges. Trends Genet 2019; 35:914-922. [DOI: 10.1016/j.tig.2019.08.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 08/07/2019] [Accepted: 08/29/2019] [Indexed: 01/22/2023]
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35
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Baker EA, Woollard A. How Weird is The Worm? Evolution of the Developmental Gene Toolkit in Caenorhabditis elegans. J Dev Biol 2019; 7:E19. [PMID: 31569401 PMCID: PMC6956190 DOI: 10.3390/jdb7040019] [Citation(s) in RCA: 5] [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: 07/15/2019] [Revised: 09/20/2019] [Accepted: 09/25/2019] [Indexed: 01/14/2023] Open
Abstract
Comparative developmental biology and comparative genomics are the cornerstones of evolutionary developmental biology. Decades of fruitful research using nematodes have produced detailed accounts of the developmental and genomic variation in the nematode phylum. Evolutionary developmental biologists are now utilising these data as a tool with which to interrogate the evolutionary basis for the similarities and differences observed in Nematoda. Nematodes have often seemed atypical compared to the rest of the animal kingdom-from their totally lineage-dependent mode of embryogenesis to their abandonment of key toolkit genes usually deployed by bilaterians for proper development-worms are notorious rule breakers of the bilaterian handbook. However, exploring the nature of these deviations is providing answers to some of the biggest questions about the evolution of animal development. For example, why is the evolvability of each embryonic stage not the same? Why can evolution sometimes tolerate the loss of genes involved in key developmental events? Lastly, why does natural selection act to radically diverge toolkit genes in number and sequence in certain taxa? In answering these questions, insight is not only being provided about the evolution of nematodes, but of all metazoans.
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Affiliation(s)
- Emily A Baker
- Department of Biochemistry, University of Oxford, South Parks Rd, Oxford OX1 3QU, UK.
| | - Alison Woollard
- Department of Biochemistry, University of Oxford, South Parks Rd, Oxford OX1 3QU, UK.
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36
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Hong RL, Riebesell M, Bumbarger DJ, Cook SJ, Carstensen HR, Sarpolaki T, Cochella L, Castrejon J, Moreno E, Sieriebriennikov B, Hobert O, Sommer RJ. Evolution of neuronal anatomy and circuitry in two highly divergent nematode species. eLife 2019; 8:47155. [PMID: 31526477 PMCID: PMC6748829 DOI: 10.7554/elife.47155] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 08/12/2019] [Indexed: 11/17/2022] Open
Abstract
The nematodes C. elegans and P. pacificus populate diverse habitats and display distinct patterns of behavior. To understand how their nervous systems have diverged, we undertook a detailed examination of the neuroanatomy of the chemosensory system of P. pacificus. Using independent features such as cell body position, axon projections and lipophilic dye uptake, we have assigned homologies between the amphid neurons, their first-layer interneurons, and several internal receptor neurons of P. pacificus and C. elegans. We found that neuronal number and soma position are highly conserved. However, the morphological elaborations of several amphid cilia are different between them, most notably in the absence of ‘winged’ cilia morphology in P. pacificus. We established a synaptic wiring diagram of amphid sensory neurons and amphid interneurons in P. pacificus and found striking patterns of conservation and divergence in connectivity relative to C. elegans, but very little changes in relative neighborhood of neuronal processes. These findings demonstrate the existence of several constraints in patterning the nervous system and suggest that major substrates for evolutionary novelty lie in the alterations of dendritic structures and synaptic connectivity. Nerve cells, also called neurons, are responsible both for sensing signals from the environment and for determining how organisms react. This means that the unique features of an animal’s nervous system underpin its characteristic behaviors. Comparing the anatomy of the nervous systems in different animals could therefore yield valuable insights into how structural and behavioral differences emerge over time. Behavioral variation often occurs even in similar-looking animals. One example is a group of microscopic worms, called nematodes. Although many nematode species exist, their overall body plans are the same, and the worms of each species contain a fixed number of cells. Despite these apparent similarities, different species of nematodes inhabit a variety of environments and may respond differently to the same signals. The main sensory organs in nematodes are called the amphid sensilla. They are used to detect chemicals, as well as other inputs from the environment such as temperature and pheromones from other nematodes. Although researchers have often speculated that the number of cells in these organs and their arrangement are broadly the same across species, their anatomy had not been studied in detail. Hong, Riebesell et al. compared the detailed structure and genetic features of the sensory systems in two distantly related species of nematode worms, Pristionchus pacificus and Caenorhabditis elegans. These two species behave in different ways, for example, P. pacificus is usually found in association with different species of beetles, while C. elegans is free-living and usually found on rotting fruit. By comparing the two, Hong, Riebesell et al. wanted to determine whether the diverse behaviors observed in the two species could be determined by differences between their sensory systems. Experiments using electron microscopy yielded several thousand high resolution images spanning the entire sensory organ. These images were then used to create detailed reconstructions of the sensory nervous system in each worm species, demonstrating that both species had the same number of sensory nerve cells, allowing one-to-one comparisons between them. Further analysis showed that while the overall structure of the neuronal connections remains the same between the two species, the neurons in P. pacificus made more diverse connections than those in C. elegans. Detailed studies of gene activity also revealed that neurons in each species switched on a slightly different group of genes, possibly indicating that each type of worm processes sensory signals in different ways. These results shed new light on how nervous systems in related species can change over time without any change in neuron count. In the future, a better understanding of these changes could link the evolution of the nervous system to the emergence of different behaviors, in both simple and more complex organisms.
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Affiliation(s)
- Ray L Hong
- Department for Integrative Evolutionary Biology, Max-Planck Institute for Developmental Biology, Tuebingen, Germany.,Department of Biology, California State University, Northridge, Northridge, United States
| | - Metta Riebesell
- Department for Integrative Evolutionary Biology, Max-Planck Institute for Developmental Biology, Tuebingen, Germany
| | - Daniel J Bumbarger
- Department for Integrative Evolutionary Biology, Max-Planck Institute for Developmental Biology, Tuebingen, Germany
| | - Steven J Cook
- Department of Biological Sciences, Columbia University, New York, United States
| | - Heather R Carstensen
- Department of Biology, California State University, Northridge, Northridge, United States
| | - Tahmineh Sarpolaki
- Department for Integrative Evolutionary Biology, Max-Planck Institute for Developmental Biology, Tuebingen, Germany
| | - Luisa Cochella
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria
| | - Jessica Castrejon
- Department of Biology, California State University, Northridge, Northridge, United States
| | - Eduardo Moreno
- Department for Integrative Evolutionary Biology, Max-Planck Institute for Developmental Biology, Tuebingen, Germany
| | - Bogdan Sieriebriennikov
- Department for Integrative Evolutionary Biology, Max-Planck Institute for Developmental Biology, Tuebingen, Germany
| | - Oliver Hobert
- Department of Biological Sciences, Columbia University, New York, United States.,Howard Hughes Medical Institute, Chevy Chase, United States
| | - Ralf J Sommer
- Department for Integrative Evolutionary Biology, Max-Planck Institute for Developmental Biology, Tuebingen, Germany
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37
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De Novo, Divergence, and Mixed Origin Contribute to the Emergence of Orphan Genes in Pristionchus Nematodes. G3-GENES GENOMES GENETICS 2019; 9:2277-2286. [PMID: 31088903 PMCID: PMC6643871 DOI: 10.1534/g3.119.400326] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Homology is a fundamental concept in comparative biology. It is extensively used at the sequence level to make phylogenetic hypotheses and functional inferences. Nonetheless, the majority of eukaryotic genomes contain large numbers of orphan genes lacking homologs in other taxa. Generally, the fraction of orphan genes is higher in genomically undersampled clades, and in the absence of closely related genomes any hypothesis about their origin and evolution remains untestable. Previously, we sequenced ten genomes with an underlying ladder-like phylogeny to establish a phylogenomic framework for studying genome evolution in diplogastrid nematodes. Here, we use this deeply sampled data set to understand the processes that generate orphan genes in our focal species Pristionchus pacificus Based on phylostratigraphic analysis and additional bioinformatic filters, we obtained 29 high-confidence candidate genes for which mechanisms of orphan origin were proposed based on manual inspection. This revealed diverse mechanisms including annotation artifacts, chimeric origin, alternative reading frame usage, and gene splitting with subsequent gain of de novo exons. In addition, we present two cases of complete de novo origination from non-coding regions, which represents one of the first reports of de novo genes in nematodes. Thus, we conclude that de novo emergence, divergence, and mixed mechanisms contribute to novel gene formation in Pristionchus nematodes.
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38
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Newman SA. Inherency of Form and Function in Animal Development and Evolution. Front Physiol 2019; 10:702. [PMID: 31275153 PMCID: PMC6593199 DOI: 10.3389/fphys.2019.00702] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 05/20/2019] [Indexed: 12/11/2022] Open
Abstract
I discuss recent work on the origins of morphology and cell-type diversification in Metazoa – collectively the animals – and propose a scenario for how these two properties became integrated, with the help of a third set of processes, cellular pattern formation, into the developmental programs seen in present-day metazoans. Inherent propensities to generate familiar forms and cell types, in essence a parts kit for the animals, are exhibited by present-day organisms and were likely more prominent in primitive ones. The structural motifs of animal bodies and organs, e.g., multilayered, hollow, elongated and segmented tissues, internal and external appendages, branched tubes, and modular endoskeletons, can be accounted for by the properties of mesoscale masses of metazoan cells. These material properties, in turn, resulted from the recruitment of “generic” physical forces and mechanisms – adhesion, contraction, polarity, chemical oscillation, diffusion – by toolkit molecules that were partly conserved from unicellular holozoan antecedents and partly novel, distributed in the different metazoan phyla in a fashion correlated with morphological complexity. The specialized functions of the terminally differentiated cell types in animals, e.g., contraction, excitability, barrier function, detoxification, excretion, were already present in ancestral unicellular organisms. These functions were implemented in metazoan differentiation in some cases using the same transcription factors as in single-celled ancestors, although controlled by regulatory mechanisms that were hybrids between earlier-evolved processes and regulatory innovations, such as enhancers. Cellular pattern formation, mediated by released morphogens interacting with biochemically responsive and excitable tissues, drew on inherent self-organizing processes in proto-metazoans to transform clusters of holozoan cells into animal embryos and organs.
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Affiliation(s)
- Stuart A Newman
- Department of Cell Biology and Anatomy, New York Medical College, Valhalla, NY, United States
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39
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Kim C, Kim J, Kim S, Cook DE, Evans KS, Andersen EC, Lee J. Long-read sequencing reveals intra-species tolerance of substantial structural variations and new subtelomere formation in C. elegans. Genome Res 2019; 29:1023-1035. [PMID: 31123081 PMCID: PMC6581047 DOI: 10.1101/gr.246082.118] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 04/22/2019] [Indexed: 12/05/2022]
Abstract
Long-read sequencing technologies have contributed greatly to comparative genomics among species and can also be applied to study genomics within a species. In this study, to determine how substantial genomic changes are generated and tolerated within a species, we sequenced a C. elegans strain, CB4856, which is one of the most genetically divergent strains compared to the N2 reference strain. For this comparison, we used the Pacific Biosciences (PacBio) RSII platform (80×, N50 read length 11.8 kb) and generated de novo genome assembly to the level of pseudochromosomes containing 76 contigs (N50 contig = 2.8 Mb). We identified structural variations that affected as many as 2694 genes, most of which are at chromosome arms. Subtelomeric regions contained the most extensive genomic rearrangements, which even created new subtelomeres in some cases. The subtelomere structure of Chromosome VR implies that ancestral telomere damage was repaired by alternative lengthening of telomeres even in the presence of a functional telomerase gene and that a new subtelomere was formed by break-induced replication. Our study demonstrates that substantial genomic changes including structural variations and new subtelomeres can be tolerated within a species, and that these changes may accumulate genetic diversity within a species.
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Affiliation(s)
- Chuna Kim
- Institute of Molecular Biology and Genetics, Seoul National University, Seoul, Korea 08826
- Department of Biological Sciences, Seoul National University, Seoul, Korea 08826
| | - Jun Kim
- Department of Biological Sciences, Seoul National University, Seoul, Korea 08826
- Research Institute of Basic Sciences, Seoul National University, Seoul, Korea 08826
| | - Sunghyun Kim
- Institute of Molecular Biology and Genetics, Seoul National University, Seoul, Korea 08826
- Department of Molecular and Computational Biology, University of Southern California, Los Angeles, California 90089, USA
| | - Daniel E Cook
- Department of Molecular Biosciences, Northwestern University, Evanston, Illinois 60208, USA
| | - Kathryn S Evans
- Department of Molecular Biosciences, Northwestern University, Evanston, Illinois 60208, USA
| | - Erik C Andersen
- Department of Molecular Biosciences, Northwestern University, Evanston, Illinois 60208, USA
| | - Junho Lee
- Institute of Molecular Biology and Genetics, Seoul National University, Seoul, Korea 08826
- Department of Biological Sciences, Seoul National University, Seoul, Korea 08826
- Research Institute of Basic Sciences, Seoul National University, Seoul, Korea 08826
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40
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Affiliation(s)
- Stephen Branden Van Oss
- Department of Computational and Systems Biology, Pittsburgh Center for Evolutionary Biology and Medicine, School of Medicine, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Anne-Ruxandra Carvunis
- Department of Computational and Systems Biology, Pittsburgh Center for Evolutionary Biology and Medicine, School of Medicine, University of Pittsburgh, Pittsburgh, PA, United States of America
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41
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Beltran T, Barroso C, Birkle TY, Stevens L, Schwartz HT, Sternberg PW, Fradin H, Gunsalus K, Piano F, Sharma G, Cerrato C, Ahringer J, Martínez-Pérez E, Blaxter M, Sarkies P. Comparative Epigenomics Reveals that RNA Polymerase II Pausing and Chromatin Domain Organization Control Nematode piRNA Biogenesis. Dev Cell 2019; 48:793-810.e6. [PMID: 30713076 PMCID: PMC6436959 DOI: 10.1016/j.devcel.2018.12.026] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 12/06/2018] [Accepted: 12/27/2018] [Indexed: 12/30/2022]
Abstract
Piwi-interacting RNAs (piRNAs) are important for genome regulation across metazoans, but their biogenesis evolves rapidly. In Caenorhabditis elegans, piRNA loci are clustered within two 3-Mb regions on chromosome IV. Each piRNA locus possesses an upstream motif that recruits RNA polymerase II to produce an ∼28 nt primary transcript. We used comparative epigenomics across nematodes to gain insight into the origin, evolution, and mechanism of nematode piRNA biogenesis. We show that the piRNA upstream motif is derived from core promoter elements controlling snRNA transcription. We describe two alternative modes of piRNA organization in nematodes: in C. elegans and closely related nematodes, piRNAs are clustered within repressive H3K27me3 chromatin, while in other species, typified by Pristionchus pacificus, piRNAs are found within introns of active genes. Additionally, we discover that piRNA production depends on sequence signals associated with RNA polymerase II pausing. We show that pausing signals synergize with chromatin to control piRNA transcription. Nematode piRNA transcription evolved from small nuclear RNA biogenesis Clustered piRNAs are produced from regulated (H3K27me3) chromatin domains Dispersed piRNAs are produced from active (H3K36me3) chromatin domains RNA polymerase II pausing determines the short (∼28 nt) length of piRNA precursors
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Affiliation(s)
- Toni Beltran
- MRC London Institute of Medical Sciences, London W12 0NN, UK; Institute of Clinical Sciences, Imperial College London, London W12 0NN, UK
| | - Consuelo Barroso
- MRC London Institute of Medical Sciences, London W12 0NN, UK; Institute of Clinical Sciences, Imperial College London, London W12 0NN, UK
| | - Timothy Y Birkle
- MRC London Institute of Medical Sciences, London W12 0NN, UK; Institute of Clinical Sciences, Imperial College London, London W12 0NN, UK
| | - Lewis Stevens
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3TF, UK
| | - Hillel T Schwartz
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Paul W Sternberg
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Hélène Fradin
- Department of Biology, New York University, New York, NY 10003, USA; Center for Genomics and Systems Biology, New York University, New York, NY 10003, USA; Center for Genomics and Systems Biology, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - Kristin Gunsalus
- Department of Biology, New York University, New York, NY 10003, USA; Center for Genomics and Systems Biology, New York University, New York, NY 10003, USA; Center for Genomics and Systems Biology, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - Fabio Piano
- Department of Biology, New York University, New York, NY 10003, USA; Center for Genomics and Systems Biology, New York University, New York, NY 10003, USA; Center for Genomics and Systems Biology, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - Garima Sharma
- The Gurdon Institute and Department of Genetics, University of Cambridge, Cambridge, UK
| | - Chiara Cerrato
- The Gurdon Institute and Department of Genetics, University of Cambridge, Cambridge, UK
| | - Julie Ahringer
- The Gurdon Institute and Department of Genetics, University of Cambridge, Cambridge, UK
| | - Enrique Martínez-Pérez
- MRC London Institute of Medical Sciences, London W12 0NN, UK; Institute of Clinical Sciences, Imperial College London, London W12 0NN, UK
| | - Mark Blaxter
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3TF, UK.
| | - Peter Sarkies
- MRC London Institute of Medical Sciences, London W12 0NN, UK; Institute of Clinical Sciences, Imperial College London, London W12 0NN, UK.
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