1
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Horvath R, Minadakis N, Bourgeois Y, Roulin AC. The evolution of transposable elements in Brachypodium distachyon is governed by purifying selection, while neutral and adaptive processes play a minor role. eLife 2024; 12:RP93284. [PMID: 38606833 PMCID: PMC11014726 DOI: 10.7554/elife.93284] [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] [Indexed: 04/13/2024] Open
Abstract
Understanding how plants adapt to changing environments and the potential contribution of transposable elements (TEs) to this process is a key question in evolutionary genomics. While TEs have recently been put forward as active players in the context of adaptation, few studies have thoroughly investigated their precise role in plant evolution. Here, we used the wild Mediterranean grass Brachypodium distachyon as a model species to identify and quantify the forces acting on TEs during the adaptation of this species to various conditions, across its entire geographic range. Using sequencing data from more than 320 natural B. distachyon accessions and a suite of population genomics approaches, we reveal that putatively adaptive TE polymorphisms are rare in wild B. distachyon populations. After accounting for changes in past TE activity, we show that only a small proportion of TE polymorphisms evolved neutrally (<10%), while the vast majority of them are under moderate purifying selection regardless of their distance to genes. TE polymorphisms should not be ignored when conducting evolutionary studies, as they can be linked to adaptation. However, our study clearly shows that while they have a large potential to cause phenotypic variation in B. distachyon, they are not favored during evolution and adaptation over other types of mutations (such as point mutations) in this species.
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Affiliation(s)
- Robert Horvath
- Department of Plant and Microbial Biology, University of ZurichZurichSwitzerland
| | - Nikolaos Minadakis
- Department of Plant and Microbial Biology, University of ZurichZurichSwitzerland
| | - Yann Bourgeois
- DIADE, University of Montpellier, CIRAD, IRDMontpellierFrance
- University of PortsmouthPortsmouthUnited Kingdom
| | - Anne C Roulin
- Department of Plant and Microbial Biology, University of ZurichZurichSwitzerland
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2
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Pasquesi GIM, Kelly CJ, Ordonez AD, Chuong EB. Transcriptional dynamics of transposable elements in the type I IFN response in Myotis lucifugus cells. Mob DNA 2022; 13:22. [PMID: 36068622 PMCID: PMC9446614 DOI: 10.1186/s13100-022-00277-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Accepted: 08/09/2022] [Indexed: 12/02/2022] Open
Abstract
Background Bats are a major reservoir of zoonotic viruses, and there has been growing interest in characterizing bat-specific features of innate immunity and inflammation. Recent studies have revealed bat-specific adaptations affecting interferon (IFN) signaling and IFN-stimulated genes (ISGs), but we still have a limited understanding of the genetic mechanisms that have shaped the evolution of bat immunity. Here we investigated the transcriptional and epigenetic dynamics of transposable elements (TEs) during the type I IFN response in little brown bat (Myotis lucifugus) primary embryonic fibroblast cells, using RNA-seq and CUT&RUN. Results We found multiple bat-specific TEs that undergo both locus-specific and family-level transcriptional induction in response to IFN. Our transcriptome reassembly identified multiple ISGs that have acquired novel exons from bat-specific TEs, including NLRC5, SLNF5 and a previously unannotated isoform of the IFITM2 gene. We also identified examples of TE-derived regulatory elements, but did not find strong evidence supporting genome-wide epigenetic activation of TEs in response to IFN. Conclusion Collectively, our study uncovers numerous TE-derived transcripts, proteins, and alternative isoforms that are induced by IFN in Myotis lucifugus cells, highlighting candidate loci that may contribute to bat-specific immune function. Supplementary Information The online version contains supplementary material available at 10.1186/s13100-022-00277-z.
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Affiliation(s)
- Giulia Irene Maria Pasquesi
- BioFrontiers Institute and Department of Molecular, Cellular & Developmental Biology, University of Colorado Boulder, 596 UCB, Boulder, CO, 80309, USA
| | - Conor J Kelly
- BioFrontiers Institute and Department of Molecular, Cellular & Developmental Biology, University of Colorado Boulder, 596 UCB, Boulder, CO, 80309, USA
| | - Andrea D Ordonez
- BioFrontiers Institute and Department of Molecular, Cellular & Developmental Biology, University of Colorado Boulder, 596 UCB, Boulder, CO, 80309, USA
| | - Edward B Chuong
- BioFrontiers Institute and Department of Molecular, Cellular & Developmental Biology, University of Colorado Boulder, 596 UCB, Boulder, CO, 80309, USA.
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3
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On the Base Composition of Transposable Elements. Int J Mol Sci 2022; 23:ijms23094755. [PMID: 35563146 PMCID: PMC9099904 DOI: 10.3390/ijms23094755] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 04/22/2022] [Accepted: 04/23/2022] [Indexed: 01/27/2023] Open
Abstract
Transposable elements exhibit a base composition that is often different from the genomic average and from hosts’ genes. The most common compositional bias is towards Adenosine and Thymine, although this bias is not universal, and elements with drastically different base composition can coexist within the same genome. The AT-richness of transposable elements is apparently maladaptive because it results in poor transcription and sub-optimal translation of proteins encoded by the elements. The cause(s) of this unusual base composition remain unclear and have yet to be investigated. Here, I review what is known about the nucleotide content of transposable elements and how this content can affect the genome of their host as well as their own replication. The compositional bias of transposable elements could result from several non-exclusive processes including horizontal transfer, mutational bias, and selection. It appears that mutation alone cannot explain the high AT-content of transposons and that selection plays a major role in the evolution of the compositional bias. The reason why selection would favor a maladaptive nucleotide content remains however unexplained and is an area of investigation that clearly deserves attention.
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4
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Tusso S, Suo F, Liang Y, Du LL, Wolf JBW. Reactivation of transposable elements following hybridization in fission yeast. Genome Res 2021; 32:324-336. [PMID: 34907076 PMCID: PMC8805722 DOI: 10.1101/gr.276056.121] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 12/09/2021] [Indexed: 11/29/2022]
Abstract
Hybridization is thought to reactivate transposable elements (TEs) that were efficiently suppressed in the genomes of the parental hosts. Here, we provide evidence for this “genomic shock hypothesis” in the fission yeast Schizosaccharomyces pombe. In this species, two divergent lineages (Sp and Sk) have experienced recent, likely human-induced, hybridization. We used long-read sequencing data to assemble genomes of 37 samples derived from 31 S. pombe strains spanning a wide range of ancestral admixture proportions. A comprehensive TE inventory revealed exclusive presence of long terminal repeat (LTR) retrotransposons. Sequence analysis of active full-length elements, as well as solo LTRs, revealed a complex history of homologous recombination. Population genetic analyses of syntenic sequences placed insertion of many solo LTRs before the split of the Sp and Sk lineages. Most full-length elements were inserted more recently, after hybridization. With the exception of a single full-length element with signs of positive selection, both solo LTRs and, in particular, full-length elements carry signatures of purifying selection indicating effective removal by the host. Consistent with reactivation upon hybridization, the number of full-length LTR retrotransposons, varying extensively from zero to 87 among strains, significantly increases with the degree of genomic admixture. This study gives a detailed account of global TE diversity in S. pombe, documents complex recombination histories within TE elements, and provides evidence for the “genomic shock hypothesis.”
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Affiliation(s)
| | - Fang Suo
- National Institute of Biological Sciences
| | - Yue Liang
- National Institute of Biological Sciences
| | - Li-Lin Du
- National Institute of Biological Sciences
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5
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Pasquesi GIM, Perry BW, Vandewege MW, Ruggiero RP, Schield DR, Castoe TA. Vertebrate Lineages Exhibit Diverse Patterns of Transposable Element Regulation and Expression across Tissues. Genome Biol Evol 2021; 12:506-521. [PMID: 32271917 PMCID: PMC7211425 DOI: 10.1093/gbe/evaa068] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/02/2020] [Indexed: 12/11/2022] Open
Abstract
Transposable elements (TEs) comprise a major fraction of vertebrate genomes, yet little is known about their expression and regulation across tissues, and how this varies across major vertebrate lineages. We present the first comparative analysis integrating TE expression and TE regulatory pathway activity in somatic and gametic tissues for a diverse set of 12 vertebrates. We conduct simultaneous gene and TE expression analyses to characterize patterns of TE expression and TE regulation across vertebrates and examine relationships between these features. We find remarkable variation in the expression of genes involved in TE negative regulation across tissues and species, yet consistently high expression in germline tissues, particularly in testes. Most vertebrates show comparably high levels of TE regulatory pathway activity across gonadal tissues except for mammals, where reduced activity of TE regulatory pathways in ovarian tissues may be the result of lower relative germ cell densities. We also find that all vertebrate lineages examined exhibit remarkably high levels of TE-derived transcripts in somatic and gametic tissues, with recently active TE families showing higher expression in gametic tissues. Although most TE-derived transcripts originate from inactive ancient TE families (and are likely incapable of transposition), such high levels of TE-derived RNA in the cytoplasm may have secondary, unappreciated biological relevance.
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Affiliation(s)
- Giulia I M Pasquesi
- Department of Biology, University of Texas at Arlington.,Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder
| | - Blair W Perry
- Department of Biology, University of Texas at Arlington
| | | | | | - Drew R Schield
- Department of Biology, University of Texas at Arlington.,Department of Ecology and Evolutionary Biology, University of Colorado, Boulder
| | - Todd A Castoe
- Department of Biology, University of Texas at Arlington
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6
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Lei L, Goltsman E, Goodstein D, Wu GA, Rokhsar DS, Vogel JP. Plant Pan-Genomics Comes of Age. ANNUAL REVIEW OF PLANT BIOLOGY 2021; 72:411-435. [PMID: 33848428 DOI: 10.1146/annurev-arplant-080720-105454] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
A pan-genome is the nonredundant collection of genes and/or DNA sequences in a species. Numerous studies have shown that plant pan-genomes are typically much larger than the genome of any individual and that a sizable fraction of the genes in any individual are present in only some genomes. The construction and interpretation of plant pan-genomes are challenging due to the large size and repetitive content of plant genomes. Most pan-genomes are largely focused on nontransposable element protein coding genes because they are more easily analyzed and defined than noncoding and repetitive sequences. Nevertheless, noncoding and repetitive DNA play important roles in determining the phenotype and genome evolution. Fortunately, it is now feasible to make multiple high-quality genomes that can be used to construct high-resolution pan-genomes that capture all the variation. However, assembling, displaying, and interacting with such high-resolution pan-genomes will require the development of new tools.
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Affiliation(s)
- Li Lei
- DOE Joint Genome Institute, Berkeley, California 94720, USA;
| | - Eugene Goltsman
- DOE Joint Genome Institute, Berkeley, California 94720, USA;
| | - David Goodstein
- DOE Joint Genome Institute, Berkeley, California 94720, USA;
| | | | - Daniel S Rokhsar
- DOE Joint Genome Institute, Berkeley, California 94720, USA;
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, USA
| | - John P Vogel
- DOE Joint Genome Institute, Berkeley, California 94720, USA;
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720, USA
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7
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Almojil D, Bourgeois Y, Falis M, Hariyani I, Wilcox J, Boissinot S. The Structural, Functional and Evolutionary Impact of Transposable Elements in Eukaryotes. Genes (Basel) 2021; 12:genes12060918. [PMID: 34203645 PMCID: PMC8232201 DOI: 10.3390/genes12060918] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2021] [Revised: 06/04/2021] [Accepted: 06/07/2021] [Indexed: 12/22/2022] Open
Abstract
Transposable elements (TEs) are nearly ubiquitous in eukaryotes. The increase in genomic data, as well as progress in genome annotation and molecular biology techniques, have revealed the vast number of ways mobile elements have impacted the evolution of eukaryotes. In addition to being the main cause of difference in haploid genome size, TEs have affected the overall organization of genomes by accumulating preferentially in some genomic regions, by causing structural rearrangements or by modifying the recombination rate. Although the vast majority of insertions is neutral or deleterious, TEs have been an important source of evolutionary novelties and have played a determinant role in the evolution of fundamental biological processes. TEs have been recruited in the regulation of host genes and are implicated in the evolution of regulatory networks. They have also served as a source of protein-coding sequences or even entire genes. The impact of TEs on eukaryotic evolution is only now being fully appreciated and the role they may play in a number of biological processes, such as speciation and adaptation, remains to be deciphered.
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Affiliation(s)
- Dareen Almojil
- New York University Abu Dhabi, Saadiyat Island, Abu Dhabi P.O. Box 129188, United Arab Emirates; (D.A.); (M.F.); (I.H.); (J.W.)
| | - Yann Bourgeois
- School of Biological Sciences, University of Portsmouth, Portsmouth, UK;
| | - Marcin Falis
- New York University Abu Dhabi, Saadiyat Island, Abu Dhabi P.O. Box 129188, United Arab Emirates; (D.A.); (M.F.); (I.H.); (J.W.)
| | - Imtiyaz Hariyani
- New York University Abu Dhabi, Saadiyat Island, Abu Dhabi P.O. Box 129188, United Arab Emirates; (D.A.); (M.F.); (I.H.); (J.W.)
| | - Justin Wilcox
- New York University Abu Dhabi, Saadiyat Island, Abu Dhabi P.O. Box 129188, United Arab Emirates; (D.A.); (M.F.); (I.H.); (J.W.)
- Center for Genomics and Systems Biology, New York University Abu Dhabi, Saadiyat Island, Abu Dhabi P.O. Box 129188, United Arab Emirates
| | - Stéphane Boissinot
- New York University Abu Dhabi, Saadiyat Island, Abu Dhabi P.O. Box 129188, United Arab Emirates; (D.A.); (M.F.); (I.H.); (J.W.)
- Center for Genomics and Systems Biology, New York University Abu Dhabi, Saadiyat Island, Abu Dhabi P.O. Box 129188, United Arab Emirates
- Correspondence:
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8
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Nowell RW, Wilson CG, Almeida P, Schiffer PH, Fontaneto D, Becks L, Rodriguez F, Arkhipova IR, Barraclough TG. Evolutionary dynamics of transposable elements in bdelloid rotifers. eLife 2021; 10:e63194. [PMID: 33543711 PMCID: PMC7943196 DOI: 10.7554/elife.63194] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 02/04/2021] [Indexed: 12/17/2022] Open
Abstract
Transposable elements (TEs) are selfish genomic parasites whose ability to spread autonomously is facilitated by sexual reproduction in their hosts. If hosts become obligately asexual, TE frequencies and dynamics are predicted to change dramatically, but the long-term outcome is unclear. Here, we test current theory using whole-genome sequence data from eight species of bdelloid rotifers, a class of invertebrates in which males are thus far unknown. Contrary to expectations, we find a variety of active TEs in bdelloid genomes, at an overall frequency within the range seen in sexual species. We find no evidence that TEs are spread by cryptic recombination or restrained by unusual DNA repair mechanisms. Instead, we find that that TE content evolves relatively slowly in bdelloids and that gene families involved in RNAi-mediated TE suppression have undergone significant expansion, which might mitigate the deleterious effects of active TEs and compensate for the consequences of long-term asexuality.
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Affiliation(s)
- Reuben W Nowell
- Department of Zoology, University of OxfordOxfordUnited Kingdom
- Department of Life Sciences, Imperial College London, Silwood Park CampusAscot, BerkshireUnited Kingdom
| | - Christopher G Wilson
- Department of Zoology, University of OxfordOxfordUnited Kingdom
- Department of Life Sciences, Imperial College London, Silwood Park CampusAscot, BerkshireUnited Kingdom
| | - Pedro Almeida
- Department of Life Sciences, Imperial College London, Silwood Park CampusAscot, BerkshireUnited Kingdom
- Division of Biosciences, University College LondonLondonUnited Kingdom
| | - Philipp H Schiffer
- Institute of Zoology, Section Developmental Biology, University of Cologne, KölnWormlabGermany
| | - Diego Fontaneto
- National Research Council of Italy, Water Research InstituteVerbania PallanzaItaly
| | - Lutz Becks
- Community Dynamics Group, Department of Evolutionary Ecology, Max Planck Institute for Evolutionary BiologyPlönGermany
- Aquatic Ecology and Evolution, University of KonstanzKonstanzGermany
| | - Fernando Rodriguez
- Josephine Bay Paul Center for Comparative Molecular Biology and Evolution, Marine Biological LaboratoryWoods Hole, MAUnited States
| | - Irina R Arkhipova
- Josephine Bay Paul Center for Comparative Molecular Biology and Evolution, Marine Biological LaboratoryWoods Hole, MAUnited States
| | - Timothy G Barraclough
- Department of Zoology, University of OxfordOxfordUnited Kingdom
- Department of Life Sciences, Imperial College London, Silwood Park CampusAscot, BerkshireUnited Kingdom
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9
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Bourgeois Y, Ruggiero RP, Hariyani I, Boissinot S. Disentangling the determinants of transposable elements dynamics in vertebrate genomes using empirical evidences and simulations. PLoS Genet 2020; 16:e1009082. [PMID: 33017388 PMCID: PMC7561263 DOI: 10.1371/journal.pgen.1009082] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 10/15/2020] [Accepted: 08/25/2020] [Indexed: 12/14/2022] Open
Abstract
The interactions between transposable elements (TEs) and their hosts constitute one of the most profound co-evolutionary processes found in nature. The population dynamics of TEs depends on factors specific to each TE families, such as the rate of transposition and insertional preference, the demographic history of the host and the genomic landscape. How these factors interact has yet to be investigated holistically. Here we are addressing this question in the green anole (Anolis carolinensis) whose genome contains an extraordinary diversity of TEs (including non-LTR retrotransposons, SINEs, LTR-retrotransposons and DNA transposons). We observed a positive correlation between recombination rate and frequency of TEs and densities for LINEs, SINEs and DNA transposons. For these elements, there was a clear impact of demography on TE frequency and abundance, with a loss of polymorphic elements and skewed frequency spectra in recently expanded populations. On the other hand, some LTR-retrotransposons displayed patterns consistent with a very recent phase of intense amplification. To determine how demography, genomic features and intrinsic properties of TEs interact we ran simulations using SLiM3. We determined that i) short TE insertions are not strongly counter-selected, but long ones are, ii) neutral demographic processes, linked selection and preferential insertion may explain positive correlations between average TE frequency and recombination, iii) TE insertions are unlikely to have been massively recruited in recent adaptation. We demonstrate that deterministic and stochastic processes have different effects on categories of TEs and that a combination of empirical analyses and simulations can disentangle these mechanisms.
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Affiliation(s)
- Yann Bourgeois
- School of Biological Sciences, University of Portsmouth, Portsmouth, United Kingdom
- New York University Abu Dhabi, Saadiyat Island Campus, Abu Dhabi, United Arab Emirates
- * E-mail: (YB); (SB)
| | - Robert P. Ruggiero
- New York University Abu Dhabi, Saadiyat Island Campus, Abu Dhabi, United Arab Emirates
- Department of Biology, Southeast Missouri State University, Cape Girardeau, MO, United States of America
| | - Imtiyaz Hariyani
- New York University Abu Dhabi, Saadiyat Island Campus, Abu Dhabi, United Arab Emirates
| | - Stéphane Boissinot
- New York University Abu Dhabi, Saadiyat Island Campus, Abu Dhabi, United Arab Emirates
- * E-mail: (YB); (SB)
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10
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Mérot C, Oomen RA, Tigano A, Wellenreuther M. A Roadmap for Understanding the Evolutionary Significance of Structural Genomic Variation. Trends Ecol Evol 2020; 35:561-572. [PMID: 32521241 DOI: 10.1016/j.tree.2020.03.002] [Citation(s) in RCA: 141] [Impact Index Per Article: 35.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 02/25/2020] [Accepted: 03/03/2020] [Indexed: 12/12/2022]
Abstract
Structural genomic variants (SVs) are ubiquitous and play a major role in adaptation and speciation. Yet, comparative and population genomics have focused predominantly on gene duplications and large-effect inversions. The lack of a common framework for studying all SVs is hampering progress towards a more systematic assessment of their evolutionary significance. Here we (i) review how different types of SVs affect ecological and evolutionary processes; (ii) suggest unifying definitions and recommendations for future studies; and (iii) provide a roadmap for the integration of SVs in ecoevolutionary studies. In doing so, we lay the foundation for population genomics, theoretical, and experimental approaches to understand how the full spectrum of SVs impacts ecological and evolutionary processes.
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Affiliation(s)
- Claire Mérot
- Université Laval, Institut de Biologie Intégrative des Systèmes, 1030 Avenue de la Médecine, G1V 0A6, Québec, QC, Canada.
| | - Rebekah A Oomen
- Centre for Ecological and Evolutionary Synthesis, University of Oslo, Blindernveien 31, 0371 Oslo, Norway; Centre for Coastal Research, University of Agder, Universitetsveien 25, 4630 Kristiansand, Norway.
| | - Anna Tigano
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, NH, USA; Hubbard Center for Genome Studies, University of New Hampshire, Durham, NH, USA.
| | - Maren Wellenreuther
- School of Biological Sciences, The University of Auckland, Auckland, New Zealand; The New Zealand Institute for Plant & Food Research Ltd, Nelson, New Zealand.
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11
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Bourgeois Y, Boissinot S. On the Population Dynamics of Junk: A Review on the Population Genomics of Transposable Elements. Genes (Basel) 2019; 10:genes10060419. [PMID: 31151307 PMCID: PMC6627506 DOI: 10.3390/genes10060419] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 05/05/2019] [Accepted: 05/21/2019] [Indexed: 01/18/2023] Open
Abstract
Transposable elements (TEs) play an important role in shaping genomic organization and structure, and may cause dramatic changes in phenotypes. Despite the genetic load they may impose on their host and their importance in microevolutionary processes such as adaptation and speciation, the number of population genetics studies focused on TEs has been rather limited so far compared to single nucleotide polymorphisms (SNPs). Here, we review the current knowledge about the dynamics of transposable elements at recent evolutionary time scales, and discuss the mechanisms that condition their abundance and frequency. We first discuss non-adaptive mechanisms such as purifying selection and the variable rates of transposition and elimination, and then focus on positive and balancing selection, to finally conclude on the potential role of TEs in causing genomic incompatibilities and eventually speciation. We also suggest possible ways to better model TEs dynamics in a population genomics context by incorporating recent advances in TEs into the rich information provided by SNPs about the demography, selection, and intrinsic properties of genomes.
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Affiliation(s)
- Yann Bourgeois
- New York University Abu Dhabi, P.O. 129188, Saadiyat Island, Abu Dhabi, United Arab Emirates.
| | - Stéphane Boissinot
- New York University Abu Dhabi, P.O. 129188, Saadiyat Island, Abu Dhabi, United Arab Emirates.
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12
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Abstract
Human brain organoids, generated from pluripotent stem cells, have emerged as a promising technique for modeling early stages of human neurodevelopment in controlled laboratory conditions. Although the applications for disease modeling in a dish have become routine, the use of these brain organoids as evolutionary tools is only now getting momentum. Here, we will review the current state of the art on the use of brain organoids from different species and the molecular and cellular insights generated from these studies. Besides, we will discuss how this model might be beneficial for human health and the limitations and future perspectives of this technology.
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Affiliation(s)
- Alysson R. Muotri
- Department of Pediatrics/Rady Children's Hospital San Diego, University of California San Diego, School of Medicine, La Jolla, CA, USA
- Department of Cellular & Molecular Medicine, University of California San Diego, School of Medicine, La Jolla, CA, USA
- UCSD Stem Cell Programme, University of California San Diego, School of Medicine, La Jolla, CA, USA
- Center for Academic Research and Training in Anthropogeny (CARTA), La Jolla, CA, USA
- Kavli Institute for Brain and Mind, University of California San Diego, School of Medicine, La Jolla, CA, USA
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13
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Blumenstiel JP. Birth, School, Work, Death, and Resurrection: The Life Stages and Dynamics of Transposable Element Proliferation. Genes (Basel) 2019; 10:genes10050336. [PMID: 31058854 PMCID: PMC6562965 DOI: 10.3390/genes10050336] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 04/18/2019] [Accepted: 04/23/2019] [Indexed: 12/18/2022] Open
Abstract
Transposable elements (TEs) can be maintained in sexually reproducing species even if they are harmful. However, the evolutionary strategies that TEs employ during proliferation can modulate their impact. In this review, I outline the different life stages of a TE lineage, from birth to proliferation to extinction. Through their interactions with the host, TEs can exploit diverse strategies that range from long-term coexistence to recurrent movement across species boundaries by horizontal transfer. TEs can also engage in a poorly understood phenomenon of TE resurrection, where TE lineages can apparently go extinct, only to proliferate again. By determining how this is possible, we may obtain new insights into the evolutionary dynamics of TEs and how they shape the genomes of their hosts.
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Affiliation(s)
- Justin P Blumenstiel
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, KS 66049, USA.
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14
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Pasquesi GIM, Adams RH, Card DC, Schield DR, Corbin AB, Perry BW, Reyes-Velasco J, Ruggiero RP, Vandewege MW, Shortt JA, Castoe TA. Squamate reptiles challenge paradigms of genomic repeat element evolution set by birds and mammals. Nat Commun 2018; 9:2774. [PMID: 30018307 PMCID: PMC6050309 DOI: 10.1038/s41467-018-05279-1] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 06/25/2018] [Indexed: 12/14/2022] Open
Abstract
Broad paradigms of vertebrate genomic repeat element evolution have been largely shaped by analyses of mammalian and avian genomes. Here, based on analyses of genomes sequenced from over 60 squamate reptiles (lizards and snakes), we show that patterns of genomic repeat landscape evolution in squamates challenge such paradigms. Despite low variance in genome size, squamate genomes exhibit surprisingly high variation among species in abundance (ca. 25–73% of the genome) and composition of identifiable repeat elements. We also demonstrate that snake genomes have experienced microsatellite seeding by transposable elements at a scale unparalleled among eukaryotes, leading to some snake genomes containing the highest microsatellite content of any known eukaryote. Our analyses of transposable element evolution across squamates also suggest that lineage-specific variation in mechanisms of transposable element activity and silencing, rather than variation in species-specific demography, may play a dominant role in driving variation in repeat element landscapes across squamate phylogeny. Large-scale patterns of genomic repeat element evolution have been studied mainly in birds and mammals. Here, the authors analyze the genomes of over 60 squamate reptiles and show high variation in repeat elements compared to mammals and birds, and particularly high microsatellite seeding in snakes.
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Affiliation(s)
- Giulia I M Pasquesi
- Department of Biology, University of Texas at Arlington, 501S. Nedderman Drive, Arlington, TX, 76019, USA
| | - Richard H Adams
- Department of Biology, University of Texas at Arlington, 501S. Nedderman Drive, Arlington, TX, 76019, USA
| | - Daren C Card
- Department of Biology, University of Texas at Arlington, 501S. Nedderman Drive, Arlington, TX, 76019, USA
| | - Drew R Schield
- Department of Biology, University of Texas at Arlington, 501S. Nedderman Drive, Arlington, TX, 76019, USA
| | - Andrew B Corbin
- Department of Biology, University of Texas at Arlington, 501S. Nedderman Drive, Arlington, TX, 76019, USA
| | - Blair W Perry
- Department of Biology, University of Texas at Arlington, 501S. Nedderman Drive, Arlington, TX, 76019, USA
| | - Jacobo Reyes-Velasco
- Department of Biology, University of Texas at Arlington, 501S. Nedderman Drive, Arlington, TX, 76019, USA.,Department of Biology, New York University Abu Dhabi, Saadiyat Island, United Arab Emirates
| | - Robert P Ruggiero
- Department of Biology, New York University Abu Dhabi, Saadiyat Island, United Arab Emirates
| | - Michael W Vandewege
- Department of Biology, Institute for Genomics and Evolutionary Medicine, Temple University, Philadelphia, PA, 19122, USA
| | - Jonathan A Shortt
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO, 80045, USA
| | - Todd A Castoe
- Department of Biology, University of Texas at Arlington, 501S. Nedderman Drive, Arlington, TX, 76019, USA.
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