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Cummins EA, Hall RJ, McInerney JO, McNally A. Prokaryote pangenomes are dynamic entities. Curr Opin Microbiol 2022; 66:73-78. [PMID: 35104691 DOI: 10.1016/j.mib.2022.01.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Revised: 01/07/2022] [Accepted: 01/11/2022] [Indexed: 11/24/2022]
Abstract
Prokaryote pangenomes are influenced heavily by environmental factors and the opportunity for gene gain and loss events. As the field of pangenome analysis has expanded, so has the need to fully understand the complexity of how eco-evolutionary dynamics shape pangenomes. Here, we describe current models of pangenome evolution and discuss their suitability and accuracy. We suggest that pangenomes are dynamic entities under constant flux, highlighting the influence of two-way interactions between pangenome and environment. New classifications of core and accessory genes are also considered, underscoring the need for continuous evaluation of nomenclature in a fast-moving field. We conclude that future models of pangenome evolution should incorporate eco-evolutionary dynamics to fully encompass their dynamic, changeable nature.
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Affiliation(s)
- Elizabeth A Cummins
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Rebecca J Hall
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT, UK.
| | - James O McInerney
- School of Life Sciences, University of Nottingham, Nottingham, NG7 2UH, UK
| | - Alan McNally
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT, UK.
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2
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Haraoui LP. Networked collective microbiomes and the rise of subcellular 'units of life'. Trends Microbiol 2021; 30:112-119. [PMID: 34696928 DOI: 10.1016/j.tim.2021.09.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 09/21/2021] [Accepted: 09/27/2021] [Indexed: 10/20/2022]
Abstract
Microbiomes are generally conceived of as one element of a pair - their partner being the habitat they occupy. I call this common scientific practice 'pair-thinking'. Research into antimicrobial resistance and its underlying anthropogenic drivers highlights the growing footprint occupied by mobile genetic elements (MGEs). Furthermore, these MGEs are known to circulate widely between microbiomes. Using a pluralistic framework anchored within a processual microbial ontology, these observations point to a reframing of microbiomes as networked and collective, thus challenging pair-thinking. Such a shift has implications for the future of microbiome research, from conceptual and methodological perspectives, and exposes the impacts of anthropogenic forces on the evolution of microbiomes and the functions they carry out.
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Affiliation(s)
- Louis-Patrick Haraoui
- Department of Microbiology and Infectious Diseases, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, Canada.
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3
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Abstract
Natural selection successfully explains how organisms accumulate adaptive change despite that traits acquired over a lifetime are eliminated at the end of each generation. However, in some domains that exhibit cumulative, adaptive change-e.g. cultural evolution, and earliest life-acquired traits are retained; these domains do not face the problem that Darwin's theory was designed to solve. Lack of transmission of acquired traits occurs when germ cells are protected from environmental change, due to a self-assembly code used in two distinct ways: (i) actively interpreted during development to generate a soma, and (ii) passively copied without interpretation during reproduction to generate germ cells. Early life and cultural evolution appear not to involve a self-assembly code used in these two ways. We suggest that cumulative, adaptive change in these domains is due to a lower-fidelity evolutionary process, and model it using reflexively autocatalytic and foodset-generated networks. We refer to this more primitive evolutionary process as self-other reorganization (SOR) because it involves internal self-organizing and self-maintaining processes within entities, as well as interaction between entities. SOR encompasses learning but in general operates across groups. We discuss the relationship between SOR and Lamarckism, and illustrate a special case of SOR without variation.
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Affiliation(s)
- Liane Gabora
- Department of Psychology, University of British Columbia, Kelowna British Columbia, Canada
| | - Mike Steel
- Biomathematics Research Centre, University of Canterbury, Christchurch, New Zealand
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4
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Han X, Guo J, Pang E, Song H, Lin K. Ab Initio Construction and Evolutionary Analysis of Protein-Coding Gene Families with Partially Homologous Relationships: Closely Related Drosophila Genomes as a Case Study. Genome Biol Evol 2021; 12:185-202. [PMID: 32108239 PMCID: PMC7144356 DOI: 10.1093/gbe/evaa041] [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] [Accepted: 02/18/2020] [Indexed: 01/05/2023] Open
Abstract
How have genes evolved within a well-known genome phylogeny? Many protein-coding genes should have evolved as a whole at the gene level, and some should have evolved partly through fragments at the subgene level. To comprehensively explore such complex homologous relationships and better understand gene family evolution, here, with de novo-identified modules, the subgene units which could consecutively cover proteins within a set of closely related species, we applied a new phylogeny-based approach that considers evolutionary models with partial homology to classify all protein-coding genes in nine Drosophila genomes. Compared with two other popular methods for gene family construction, our approach improved practical gene family classifications with a more reasonable view of homology and provided a much more complete landscape of gene family evolution at the gene and subgene levels. In the case study, we found that most expanded gene families might have evolved mainly through module rearrangements rather than gene duplications and mainly generated single-module genes through partial gene duplication, suggesting that there might be pervasive subgene rearrangement in the evolution of protein-coding gene families. The use of a phylogeny-based approach with partial homology to classify and analyze protein-coding gene families may provide us with a more comprehensive landscape depicting how genes evolve within a well-known genome phylogeny.
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Affiliation(s)
- Xia Han
- State Key Laboratory of Earth Surface Processes and Resource Ecology, Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, College of Life Sciences, Beijing Normal University, China
| | - Jindan Guo
- State Key Laboratory of Earth Surface Processes and Resource Ecology, Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, College of Life Sciences, Beijing Normal University, China
| | - Erli Pang
- State Key Laboratory of Earth Surface Processes and Resource Ecology, Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, College of Life Sciences, Beijing Normal University, China
| | - Hongtao Song
- State Key Laboratory of Earth Surface Processes and Resource Ecology, Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, College of Life Sciences, Beijing Normal University, China
| | - Kui Lin
- State Key Laboratory of Earth Surface Processes and Resource Ecology, Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, College of Life Sciences, Beijing Normal University, China
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5
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Shuffling type of biological evolution based on horizontal gene transfer and the biosphere gene pool hypothesis. Biosystems 2020; 193-194:104131. [DOI: 10.1016/j.biosystems.2020.104131] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 03/12/2020] [Accepted: 03/12/2020] [Indexed: 02/08/2023]
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6
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Ou Y, McInerney JO. Eukaryote Genes Are More Likely than Prokaryote Genes to Be Composites. Genes (Basel) 2019; 10:genes10090648. [PMID: 31466252 PMCID: PMC6769587 DOI: 10.3390/genes10090648] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 08/18/2019] [Accepted: 08/23/2019] [Indexed: 12/27/2022] Open
Abstract
The formation of new genes by combining parts of existing genes is an important evolutionary process. Remodelled genes, which we call composites, have been investigated in many species, however, their distribution across all of life is still unknown. We set out to examine the extent to which genomes from cells and mobile genetic elements contain composite genes. We identify composite genes as those that show partial homology to at least two unrelated component genes. In order to identify composite and component genes, we constructed sequence similarity networks (SSNs) of more than one million genes from all three domains of life, as well as viruses and plasmids. We identified non-transitive triplets of nodes in this network and explored the homology relationships in these triplets to see if the middle nodes were indeed composite genes. In total, we identified 221,043 (18.57%) composites genes, which were distributed across all genomic and functional categories. In particular, the presence of composite genes is statistically more likely in eukaryotes than prokaryotes.
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Affiliation(s)
- Yaqing Ou
- Division of Evolution and Genomic Sciences, School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PL, UK.
| | - James O McInerney
- Division of Evolution and Genomic Sciences, School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PL, UK.
- School of Life Sciences, University of Nottingham, Nottingham NG7 2UH, UK.
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7
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Browne AS, Biggs PJ, Wilkinson DA, Cookson AL, Midwinter AC, Bloomfield SJ, Hranac CR, Rogers LE, Marshall JC, Benschop J, Withers H, Hathaway S, George T, Jaros P, Irshad H, Fong Y, Dufour M, Karki N, Winkleman T, French NP. Use of Genomics to Investigate Historical Importation of Shiga Toxin-Producing Escherichia coli Serogroup O26 and Nontoxigenic Variants into New Zealand. Emerg Infect Dis 2019; 25:489-500. [PMID: 30789138 PMCID: PMC6390770 DOI: 10.3201/eid2503.180899] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Shiga toxin-producing Escherichia coli serogroup O26 is an important public health pathogen. Phylogenetic bacterial lineages in a country can be associated with the level and timing of international imports of live cattle, the main reservoir. We sequenced the genomes of 152 E. coli O26 isolates from New Zealand and compared them with 252 E. coli O26 genomes from 14 other countries. Gene variation among isolates from humans, animals, and food was strongly associated with country of origin and stx toxin profile but not isolation source. Time of origin estimates indicate serogroup O26 sequence type 21 was introduced at least 3 times into New Zealand from the 1920s to the 1980s, whereas nonvirulent O26 sequence type 29 strains were introduced during the early 2000s. New Zealand's remarkably fewer introductions of Shiga toxin-producing Escherichia coli O26 compared with other countries (such as Japan) might be related to patterns of trade in live cattle.
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Corel E, Méheust R, Watson AK, McInerney JO, Lopez P, Bapteste E. Bipartite Network Analysis of Gene Sharings in the Microbial World. Mol Biol Evol 2019; 35:899-913. [PMID: 29346651 PMCID: PMC5888944 DOI: 10.1093/molbev/msy001] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Extensive microbial gene flows affect how we understand virology, microbiology, medical sciences, genetic modification, and evolutionary biology. Phylogenies only provide a narrow view of these gene flows: plasmids and viruses, lacking core genes, cannot be attached to cellular life on phylogenetic trees. Yet viruses and plasmids have a major impact on cellular evolution, affecting both the gene content and the dynamics of microbial communities. Using bipartite graphs that connect up to 149,000 clusters of homologous genes with 8,217 related and unrelated genomes, we can in particular show patterns of gene sharing that do not map neatly with the organismal phylogeny. Homologous genes are recycled by lateral gene transfer, and multiple copies of homologous genes are carried by otherwise completely unrelated (and possibly nested) genomes, that is, viruses, plasmids and prokaryotes. When a homologous gene is present on at least one plasmid or virus and at least one chromosome, a process of "gene externalization," affected by a postprocessed selected functional bias, takes place, especially in Bacteria. Bipartite graphs give us a view of vertical and horizontal gene flow beyond classic taxonomy on a single very large, analytically tractable, graph that goes beyond the cellular Web of Life.
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Affiliation(s)
- Eduardo Corel
- Unité Mixte de Recherche 7138 Evolution Paris-Seine, Centre National de la Recherche Scientifique, Institut de Biologie Paris-Seine, Sorbonne Université, Université Pierre et Marie Curie, Paris, France
| | - Raphaël Méheust
- Unité Mixte de Recherche 7138 Evolution Paris-Seine, Centre National de la Recherche Scientifique, Institut de Biologie Paris-Seine, Sorbonne Université, Université Pierre et Marie Curie, Paris, France
| | - Andrew K Watson
- Unité Mixte de Recherche 7138 Evolution Paris-Seine, Centre National de la Recherche Scientifique, Institut de Biologie Paris-Seine, Sorbonne Université, Université Pierre et Marie Curie, Paris, France
| | - James O McInerney
- Chair in Evolutionary Biology, The University of Manchester, United Kingdom
| | - Philippe Lopez
- Unité Mixte de Recherche 7138 Evolution Paris-Seine, Centre National de la Recherche Scientifique, Institut de Biologie Paris-Seine, Sorbonne Université, Université Pierre et Marie Curie, Paris, France
| | - Eric Bapteste
- Unité Mixte de Recherche 7138 Evolution Paris-Seine, Centre National de la Recherche Scientifique, Institut de Biologie Paris-Seine, Sorbonne Université, Université Pierre et Marie Curie, Paris, France
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9
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Palmer M, Venter SN, Coetzee MP, Steenkamp ET. Prokaryotic species are sui generis evolutionary units. Syst Appl Microbiol 2019; 42:145-158. [DOI: 10.1016/j.syapm.2018.10.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 10/02/2018] [Accepted: 10/03/2018] [Indexed: 12/25/2022]
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10
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Watson AK, Lannes R, Pathmanathan JS, Méheust R, Karkar S, Colson P, Corel E, Lopez P, Bapteste E. The Methodology Behind Network Thinking: Graphs to Analyze Microbial Complexity and Evolution. Methods Mol Biol 2019; 1910:271-308. [PMID: 31278668 DOI: 10.1007/978-1-4939-9074-0_9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
In the post genomic era, large and complex molecular datasets from genome and metagenome sequencing projects expand the limits of what is possible for bioinformatic analyses. Network-based methods are increasingly used to complement phylogenetic analysis in studies in molecular evolution, including comparative genomics, classification, and ecological studies. Using network methods, the vertical and horizontal relationships between all genes or genomes, whether they are from cellular chromosomes or mobile genetic elements, can be explored in a single expandable graph. In recent years, development of new methods for the construction and analysis of networks has helped to broaden the availability of these approaches from programmers to a diversity of users. This chapter introduces the different kinds of networks based on sequence similarity that are already available to tackle a wide range of biological questions, including sequence similarity networks, gene-sharing networks and bipartite graphs, and a guide for their construction and analyses.
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Affiliation(s)
- Andrew K Watson
- Sorbonne Universités, Institut de Biologie Paris-Seine, UPMC Université Paris 6, Paris, France
| | - Romain Lannes
- Sorbonne Universités, Institut de Biologie Paris-Seine, UPMC Université Paris 6, Paris, France
| | - Jananan S Pathmanathan
- Sorbonne Universités, Institut de Biologie Paris-Seine, UPMC Université Paris 6, Paris, France
| | - Raphaël Méheust
- Sorbonne Universités, Institut de Biologie Paris-Seine, UPMC Université Paris 6, Paris, France
| | - Slim Karkar
- Sorbonne Universités, Institut de Biologie Paris-Seine, UPMC Université Paris 6, Paris, France
- Department of Ecology, Evolution, and Natural Resources, School of Environmental and Biological Sciences, Rutgers, The State University of NJ, New Brunswick, NJ, USA
| | - Philippe Colson
- Fondation Institut Hospitalo-Universitaire Méditerranée Infection, Pôle des Maladies Infectieuses et Tropicales Clinique et Biologique, Fédération de Bactériologie-Hygiène-Virologie, Centre Hospitalo-Universitaire Tione, Assistance Publique-Hôpitaux de Marseille, Marseille, France
- Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes (URMITE) UM63, CNRS 7278, IRD 198, INSERM U1095, Aix-Marseille University, Marseille, France
| | - Eduardo Corel
- Sorbonne Universités, Institut de Biologie Paris-Seine, UPMC Université Paris 6, Paris, France
| | - Philippe Lopez
- Sorbonne Universités, Institut de Biologie Paris-Seine, UPMC Université Paris 6, Paris, France
| | - Eric Bapteste
- Sorbonne Universités, Institut de Biologie Paris-Seine, UPMC Université Paris 6, Paris, France.
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11
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Abstract
Understanding how an animal organism and its gut microbes form an integrated biological organization, known as a holobiont, is becoming a central issue in biological studies. Such an organization inevitably involves a complex web of transmission processes that occur on different scales in time and space, across microbes and hosts. Network-based models are introduced in this chapter to tackle aspects of this complexity and to better take into account vertical and horizontal dimensions of transmission. Two types of network-based models are presented, sequence similarity networks and bipartite graphs. One interest of these networks is that they can consider a rich diversity of important players in microbial evolution that are usually excluded from evolutionary studies, like plasmids and viruses. These methods bring forward the notion of "gene externalization," which is defined as the presence of redundant copies of prokaryotic genes on mobile genetic elements (MGEs), and therefore emphasizes a related although distinct process from lateral gene transfer between microbial cells. This chapter introduces guidelines to the construction of these networks, reviews their analysis, and illustrates their possible biological interpretations and uses. The application to human gut microbiomes shows that sequences present in a higher diversity of MGEs have both biased functions and a broader microbial and human host range. These results suggest that an "externalized gut metagenome" is partly common to humans and benefits the gut microbial community. We conclude that testing relationships between microbial genes, microbes, and their animal hosts, using network-based methods, could help to unravel additional mechanisms of transmission in holobionts.
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12
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Baquero F. Transmission as a basic process in microbial biology. Lwoff Award Prize Lecture. FEMS Microbiol Rev 2018; 41:816-827. [PMID: 29136422 DOI: 10.1093/femsre/fux042] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2017] [Accepted: 07/24/2017] [Indexed: 12/12/2022] Open
Abstract
Transmission is a basic process in biology and evolution, as it communicates different biological entities within and across hierarchical levels (from genes to holobionts) both in time and space. Vertical descent, replication, is transmission of information across generations (in the time dimension), and horizontal descent is transmission of information across compartments (in the space dimension). Transmission is essentially a communication process that can be studied by analogy of the classic information theory, based on 'emitters', 'messages' and 'receivers'. The analogy can be easily extended to the triad 'emigration', 'migration' and 'immigration'. A number of causes (forces) determine the emission, and another set of causes (energies) assures the reception. The message in fact is essentially constituted by 'meaningful' biological entities. A DNA sequence, a cell and a population have a semiotic dimension, are 'signs' that are eventually recognized (decoded) and integrated by receiver biological entities. In cis-acting or unenclosed transmission, the emitters and receivers correspond to separated entities of the same hierarchical level; in trans-acting or embedded transmission, the information flows between different, but frequently nested, hierarchical levels. The result (as in introgressive events) is constantly producing innovation and feeding natural selection, influencing also the evolution of transmission processes. This review is based on the concepts presented at the André Lwoff Award Lecture in the FEMS Microbiology Congress in Maastricht in 2015.
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Affiliation(s)
- Fernando Baquero
- Department of Microbiology, Ramón y Cajal University Hospital, Division of Biology and Evolution of Microorganisms, Ramón y Cajal Institute for Health Research (IRYCIS), Consorcio de Investigación Biomédica en Red de Epidemiología y Salud Pública, de Colmenar km 9,100, 28034 Madrid, Spain
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13
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Muraille E. Diversity Generator Mechanisms Are Essential Components of Biological Systems: The Two Queen Hypothesis. Front Microbiol 2018; 9:223. [PMID: 29487592 PMCID: PMC5816788 DOI: 10.3389/fmicb.2018.00223] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 01/30/2018] [Indexed: 01/02/2023] Open
Abstract
Diversity is widely known to fuel adaptation and evolutionary processes and increase robustness at the population, species and ecosystem levels. The Neo-Darwinian paradigm proposes that the diversity of biological entities is the consequence of genetic changes arising spontaneously and randomly, without regard for their usefulness. However, a growing body of evidence demonstrates that the evolutionary process has shaped mechanisms, such as horizontal gene transfer mechanisms, meiosis and the adaptive immune system, which has resulted in the regulated generation of diversity among populations. Though their origins are unrelated, these diversity generator (DG) mechanisms share common functional properties. They (i) contribute to the great unpredictability of the composition and/or behavior of biological systems, (ii) favor robustness and collectivism among populations and (iii) operate mainly by manipulating the systems that control the interaction of living beings with their environment. The definition proposed here for DGs is based on these properties and can be used to identify them according to function. Interestingly, prokaryotic DGs appear to be mainly reactive, as they generate diversity in response to environmental stress. They are involved in the widely described Red Queen/arms race/Cairnsian dynamic. The emergence of multicellular organisms harboring K selection traits (longer reproductive life cycle and smaller population size) has led to the acquisition of a new class of DGs that act anticipatively to stress pressures and generate a distinct dynamic called the “White Queen” here. The existence of DGs leads to the view of evolution as a more “intelligent” and Lamarckian-like process. Their repeated selection during evolution could be a neglected example of convergent evolution and suggests that some parts of the evolutionary process are tightly constrained by ecological factors, such as the population size, the generation time and the intensity of selective pressure. The ubiquity of DGs also suggests that regulated auto-generation of diversity is a fundamental property of life.
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Affiliation(s)
- Eric Muraille
- Laboratoire de Parasitologie, Faculté de Médecine, Université Libre de Bruxelles, Brussels, Belgium
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14
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Palmer M, Steenkamp ET, Coetzee MPA, Blom J, Venter SN. Genome-Based Characterization of Biological Processes That Differentiate Closely Related Bacteria. Front Microbiol 2018; 9:113. [PMID: 29467735 PMCID: PMC5808187 DOI: 10.3389/fmicb.2018.00113] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Accepted: 01/17/2018] [Indexed: 12/21/2022] Open
Abstract
Bacteriologists have strived toward attaining a natural classification system based on evolutionary relationships for nearly 100 years. In the early twentieth century it was accepted that a phylogeny-based system would be the most appropriate, but in the absence of molecular data, this approach proved exceedingly difficult. Subsequent technical advances and the increasing availability of genome sequencing have allowed for the generation of robust phylogenies at all taxonomic levels. In this study, we explored the possibility of linking biological characters to higher-level taxonomic groups in bacteria by making use of whole genome sequence information. For this purpose, we specifically targeted the genus Pantoea and its four main lineages. The shared gene sets were determined for Pantoea, the four lineages within the genus, as well as its sister-genus Tatumella. This was followed by functional characterization of the gene sets using the Kyoto Encyclopedia of Genes and Genomes (KEGG) database. In comparison to Tatumella, various traits involved in nutrient cycling were identified within Pantoea, providing evidence for increased efficacy in recycling of metabolites within the genus. Additionally, a number of traits associated with pathogenicity were identified within species often associated with opportunistic infections, with some support for adaptation toward overcoming host defenses. Some traits were also only conserved within specific lineages, potentially acquired in an ancestor to the lineage and subsequently maintained. It was also observed that the species isolated from the most diverse sources were generally the most versatile in their carbon metabolism. By investigating evolution, based on the more variable genomic regions, it may be possible to detect biologically relevant differences associated with the course of evolution and speciation.
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Affiliation(s)
- Marike Palmer
- Department of Microbiology and Plant Pathology, Forestry and Agricultural Biotechnology Institute, University of Pretoria, Pretoria, South Africa
| | - Emma T Steenkamp
- Department of Microbiology and Plant Pathology, Forestry and Agricultural Biotechnology Institute, University of Pretoria, Pretoria, South Africa
| | - Martin P A Coetzee
- Department of Genetic, Forestry and Agricultural Biotechnology Institute, University of Pretoria, Pretoria, South Africa
| | - Jochen Blom
- Bioinformatics and Systems Biology, Justus-Liebig-University Giessen, Giessen, Germany
| | - Stephanus N Venter
- Department of Microbiology and Plant Pathology, Forestry and Agricultural Biotechnology Institute, University of Pretoria, Pretoria, South Africa
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15
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Updating the genomic taxonomy and epidemiology of Campylobacter hyointestinalis. Sci Rep 2018; 8:2393. [PMID: 29403020 PMCID: PMC5799301 DOI: 10.1038/s41598-018-20889-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 01/25/2018] [Indexed: 12/24/2022] Open
Abstract
Campylobacter hyointestinalis is a member of an emerging group of zoonotic Campylobacter spp. that are increasingly identified in both gastric and non-gastric disease in humans. Here, we discovered C. hyointestinalis in three separate classes of New Zealand ruminant livestock; cattle, sheep and deer. To investigate the relevance of these findings we performed a systematic literature review on global C. hyointestinalis epidemiology and used comparative genomics to better understand and classify members of the species. We found that C. hyointestinalis subspecies hyointestinalis has an open pangenome, with accessory gene contents involved in many essential processes such as metabolism, virulence and defence. We observed that horizontal gene transfer is likely to have played an overwhelming role in species diversification, favouring a public-goods-like mechanism of gene ‘acquisition and resampling’ over a tree-of-life-like vertical inheritance model of evolution. As a result, simplistic gene-based inferences of taxonomy by similarity are likely to be misleading. Such genomic plasticity will also mean that local evolutionary histories likely influence key species characteristics, such as host-association and virulence. This may help explain geographical differences in reported C. hyointestinalis epidemiology and limits what characteristics may be generalised, requiring further genomic studies of C. hyointestinalis in areas where it causes disease.
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16
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McInerney JO, Erwin DH. The role of public goods in planetary evolution. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2017; 375:rsta.2016.0359. [PMID: 29133456 PMCID: PMC5686413 DOI: 10.1098/rsta.2016.0359] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 09/13/2017] [Indexed: 06/07/2023]
Abstract
Biological public goods are broadly shared within an ecosystem and readily available. They appear to be widespread and may have played important roles in the history of life on Earth. Of particular importance to events in the early history of life are the roles of public goods in the merging of genomes, protein domains and even cells. We suggest that public goods facilitated the origin of the eukaryotic cell, a classic major evolutionary transition. The recognition of genomic public goods challenges advocates of a direct graph view of phylogeny, and those who deny that any useful phylogenetic signal persists in modern genomes. Ecological spillovers generate public goods that provide new ecological opportunities.This article is part of the themed issue 'Reconceptualizing the origins of life'.
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Affiliation(s)
- James O McInerney
- Division of Evolution and Genomic Sciences, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester M13 9PL, UK
| | - Douglas H Erwin
- Department of Paleobiology, MRC-121, Smithsonian Institution, Washington, DC, USA
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17
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Koonin EV. Viruses and mobile elements as drivers of evolutionary transitions. Philos Trans R Soc Lond B Biol Sci 2017; 371:rstb.2015.0442. [PMID: 27431520 PMCID: PMC4958936 DOI: 10.1098/rstb.2015.0442] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/15/2016] [Indexed: 12/22/2022] Open
Abstract
The history of life is punctuated by evolutionary transitions which engender emergence of new levels of biological organization that involves selection acting at increasingly complex ensembles of biological entities. Major evolutionary transitions include the origin of prokaryotic and then eukaryotic cells, multicellular organisms and eusocial animals. All or nearly all cellular life forms are hosts to diverse selfish genetic elements with various levels of autonomy including plasmids, transposons and viruses. I present evidence that, at least up to and including the origin of multicellularity, evolutionary transitions are driven by the coevolution of hosts with these genetic parasites along with sharing of ‘public goods’. Selfish elements drive evolutionary transitions at two distinct levels. First, mathematical modelling of evolutionary processes, such as evolution of primitive replicator populations or unicellular organisms, indicates that only increasing organizational complexity, e.g. emergence of multicellular aggregates, can prevent the collapse of the host–parasite system under the pressure of parasites. Second, comparative genomic analysis reveals numerous cases of recruitment of genes with essential functions in cellular life forms, including those that enable evolutionary transitions. This article is part of the themed issue ‘The major synthetic evolutionary transitions’.
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Affiliation(s)
- Eugene V Koonin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
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Roughgarden J, Gilbert SF, Rosenberg E, Zilber-Rosenberg I, Lloyd EA. Holobionts as Units of Selection and a Model of Their Population Dynamics and Evolution. ACTA ACUST UNITED AC 2017. [DOI: 10.1007/s13752-017-0287-1] [Citation(s) in RCA: 102] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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19
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Furcation and fusion: The phylogenetics of evolutionary novelty. Dev Biol 2017; 431:69-76. [DOI: 10.1016/j.ydbio.2017.09.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Revised: 09/11/2017] [Accepted: 09/11/2017] [Indexed: 01/02/2023]
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20
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Toman J, Flegr J. Stability-based sorting: The forgotten process behind (not only) biological evolution. J Theor Biol 2017; 435:29-41. [PMID: 28899756 DOI: 10.1016/j.jtbi.2017.09.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 08/11/2017] [Accepted: 09/01/2017] [Indexed: 11/19/2022]
Abstract
Natural selection is considered to be the main process that drives biological evolution. It requires selected entities to originate dependent upon one another by the means of reproduction or copying, and for the progeny to inherit the qualities of their ancestors. However, natural selection is a manifestation of a more general persistence principle, whose temporal consequences we propose to name "stability-based sorting" (SBS). Sorting based on static stability, i.e., SBS in its strict sense and usual conception, favours characters that increase the persistence of their holders and act on all material and immaterial entities. Sorted entities could originate independently from each other, are not required to propagate and need not exhibit heredity. Natural selection is a specific form of SBS-sorting based on dynamic stability. It requires some form of heredity and is based on competition for the largest difference between the speed of generating its own copies and their expiration. SBS in its strict sense and selection thus have markedly different evolutionary consequences that are stressed in this paper. In contrast to selection, which is opportunistic, SBS is able to accumulate even momentarily detrimental characters that are advantageous for the long-term persistence of sorted entities. However, it lacks the amplification effect based on the preferential propagation of holders of advantageous characters. Thus, it works slower than selection and normally is unable to create complex adaptations. From a long-term perspective, SBS is a decisive force in evolution-especially macroevolution. SBS offers a new explanation for numerous evolutionary phenomena, including broad distribution and persistence of sexuality, altruistic behaviour, horizontal gene transfer, patterns of evolutionary stasis, planetary homeostasis, increasing ecosystem resistance to disturbances, and the universal decline of disparity in the evolution of metazoan lineages. SBS acts on all levels in all biotic and abiotic systems. It could be the only truly universal evolutionary process, and an explanatory framework based on SBS could provide new insight into the evolution of complex abiotic and biotic systems.
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Affiliation(s)
- Jan Toman
- Laboratory of Evolutionary Biology, Department of Philosophy and History of Sciences, Faculty of Science, Charles University in Prague, Vinicna 7, 128 00 Prague 2, Czech Republic.
| | - Jaroslav Flegr
- Laboratory of Evolutionary Biology, Department of Philosophy and History of Sciences, Faculty of Science, Charles University in Prague, Vinicna 7, 128 00 Prague 2, Czech Republic.
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21
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Blokesch M. In and out-contribution of natural transformation to the shuffling of large genomic regions. Curr Opin Microbiol 2017; 38:22-29. [PMID: 28458094 DOI: 10.1016/j.mib.2017.04.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Revised: 04/01/2017] [Accepted: 04/06/2017] [Indexed: 01/28/2023]
Abstract
Naturally competent bacteria can pull free DNA from their surroundings. This incoming DNA can serve various purposes, ranging from acting as a source of nutrients or DNA stretches for repair to the acquisition of novel genetic information. The latter process defines the natural competence for transformation as a mode of horizontal gene transfer (HGT) and led to its discovery almost a century ago. However, although it is widely accepted that natural competence can contribute to the spread of genetic material among prokaryotes, the question remains whether this mode of HGT can foster the transfer of larger DNA regions or only transfers shorter fragments, given that extracellular DNA is often heavily fragmented. Here, I outline examples of competence-mediated movement of large genomic segments. Moreover, I discuss a recent proposition that transformation is used to cure bacteria of selfish mobile genetic elements. Such a transformation-mediated genome maintenance mechanism could indeed be an important and underappreciated function of natural competence.
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Affiliation(s)
- Melanie Blokesch
- Laboratory of Molecular Microbiology, Global Health Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
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22
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23
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Rodríguez-Torres MD, Islas-Robles Á, Gómez-Lunar Z, Delaye L, Hernández-González I, Souza V, Travisano M, Olmedo-Álvarez G. Phenotypic Microdiversity and Phylogenetic Signal Analysis of Traits Related to Social Interaction in Bacillus spp. from Sediment Communities. Front Microbiol 2017; 8:29. [PMID: 28194138 PMCID: PMC5276817 DOI: 10.3389/fmicb.2017.00029] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Accepted: 01/05/2017] [Indexed: 12/14/2022] Open
Abstract
Understanding the relationship between phylogeny and predicted traits is important to uncover the dimension of the predictive power of a microbial composition approach. Numerous works have addressed the taxonomic composition of bacteria in communities, but little is known about trait heterogeneity in closely related bacteria that co-occur in communities. We evaluated a sample of 467 isolates from the Churince water system of the Cuatro Cienegas Basin (CCB), enriched for Bacillus spp. The 16S rRNA gene revealed a random distribution of taxonomic groups within this genus among 11 sampling sites. A subsample of 141 Bacillus spp. isolates from sediment, with seven well-represented species was chosen to evaluate the heterogeneity and the phylogenetic signal of phenotypic traits that are known to diverge within small clades, such as substrate utilization, and traits that are conserved deep in the lineage, such as prototrophy, swarming and biofilm formation. We were especially interested in evaluating social traits, such as swarming and biofilm formation, for which cooperation is needed to accomplish a multicellular behavior and for which there is little information from natural communities. The phylogenetic distribution of traits, evaluated by the Purvis and Fritz’s D statistics approached a Brownian model of evolution. Analysis of the phylogenetic relatedness of the clusters of members sharing the trait using consenTRAIT algorithm, revealed more clustering and deeper phylogenetic signal for prototrophy, biofilm and swimming compared to the data obtained for substrate utilization. The explanation to the observed Brownian evolution of social traits could be either loss due to complete dispensability or to compensated trait loss due to the availability of public goods. Since many of the evaluated traits can be considered to be collective action traits, such as swarming, motility and biofilm formation, the observed microdiversity within taxonomic groups might be explained by distributed functions in structured communities.
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Affiliation(s)
- María Dolores Rodríguez-Torres
- Laboratorio de Biología Molecular y Ecología Microbiana, Departamento de Ingeniería Genética, Unidad Irapuato, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional Irapuato, México
| | - África Islas-Robles
- Laboratorio de Biología Molecular y Ecología Microbiana, Departamento de Ingeniería Genética, Unidad Irapuato, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional Irapuato, México
| | - Zulema Gómez-Lunar
- Laboratorio de Biología Molecular y Ecología Microbiana, Departamento de Ingeniería Genética, Unidad Irapuato, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional Irapuato, México
| | - Luis Delaye
- Laboratorio de Biología Molecular y Ecología Microbiana, Departamento de Ingeniería Genética, Unidad Irapuato, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional Irapuato, México
| | - Ismael Hernández-González
- Laboratorio de Biología Molecular y Ecología Microbiana, Departamento de Ingeniería Genética, Unidad Irapuato, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional Irapuato, México
| | - Valeria Souza
- Laboratorio de Evolución Molecular y Experimental, Departamento de Ecología Evolutiva, Instituto de Ecología Universidad Nacional Autónoma de México Mexico City, México
| | - Michael Travisano
- Department of Ecology, Evolution and Behavior, University of Minnesota, Saint Paul MN, USA
| | - Gabriela Olmedo-Álvarez
- Laboratorio de Biología Molecular y Ecología Microbiana, Departamento de Ingeniería Genética, Unidad Irapuato, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional Irapuato, México
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Booth A, Mariscal C, Doolittle WF. The Modern Synthesis in the Light of Microbial Genomics. Annu Rev Microbiol 2016; 70:279-97. [DOI: 10.1146/annurev-micro-102215-095456] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Austin Booth
- Department of Philosophy, Dalhousie University, Halifax B3H 4R2, Nova Scotia, Canada
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax B3H 4R2, Nova Scotia, Canada;
| | - Carlos Mariscal
- Department of Philosophy, Dalhousie University, Halifax B3H 4R2, Nova Scotia, Canada
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax B3H 4R2, Nova Scotia, Canada;
- Department of Philosophy, University of Nevada, Reno, Nevada 89557
| | - W. Ford Doolittle
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax B3H 4R2, Nova Scotia, Canada;
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25
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26
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Hanage WP. Not So Simple After All: Bacteria, Their Population Genetics, and Recombination. Cold Spring Harb Perspect Biol 2016; 8:cshperspect.a018069. [PMID: 27091940 DOI: 10.1101/cshperspect.a018069] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The pervasive nature of bacterial recombination has become clear. Despite this, the population genetics of bacteria persist in being viewed as simple. Here, I argue against that characterization. After summarizing the history of the topic, I survey the evidence for remarkable and unexplained variation in recombination rate among and within bacterial species. I finally argue that despite recent assertions that recombination means bacterial genes are "public goods," in bacteria the level of selection is the gene, and genes can be understood to have niches with dimensions including the other contents of the genome in which they find themselves.
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Affiliation(s)
- William P Hanage
- Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, Massachusetts 02115
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27
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McInerney J, Pisani D, O'Connell MJ. The ring of life hypothesis for eukaryote origins is supported by multiple kinds of data. Philos Trans R Soc Lond B Biol Sci 2016; 370:20140323. [PMID: 26323755 DOI: 10.1098/rstb.2014.0323] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The literature is replete with manuscripts describing the origin of eukaryotic cells. Most of the models for eukaryogenesis are either autogenous (sometimes called slow-drip), or symbiogenic (sometimes called big-bang). In this article, we use large and diverse suites of 'Omics' and other data to make the inference that autogeneous hypotheses are a very poor fit to the data and the origin of eukaryotic cells occurred in a single symbiosis.
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Affiliation(s)
- James McInerney
- Department of Biology, National University of Ireland Maynooth, Co. Kildare, Republic of Ireland Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Davide Pisani
- School of Biological Sciences and School of Earth Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol BS8 1TG, UK
| | - Mary J O'Connell
- School of Biotechnology, Dublin City University, Glasnevin, Dublin 9, Republic of Ireland
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28
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Bhattacharya D, Agrawal S, Aranda M, Baumgarten S, Belcaid M, Drake JL, Erwin D, Foret S, Gates RD, Gruber DF, Kamel B, Lesser MP, Levy O, Liew YJ, MacManes M, Mass T, Medina M, Mehr S, Meyer E, Price DC, Putnam HM, Qiu H, Shinzato C, Shoguchi E, Stokes AJ, Tambutté S, Tchernov D, Voolstra CR, Wagner N, Walker CW, Weber AP, Weis V, Zelzion E, Zoccola D, Falkowski PG. Comparative genomics explains the evolutionary success of reef-forming corals. eLife 2016; 5. [PMID: 27218454 PMCID: PMC4878875 DOI: 10.7554/elife.13288] [Citation(s) in RCA: 118] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Accepted: 04/20/2016] [Indexed: 12/30/2022] Open
Abstract
Transcriptome and genome data from twenty stony coral species and a selection of reference bilaterians were studied to elucidate coral evolutionary history. We identified genes that encode the proteins responsible for the precipitation and aggregation of the aragonite skeleton on which the organisms live, and revealed a network of environmental sensors that coordinate responses of the host animals to temperature, light, and pH. Furthermore, we describe a variety of stress-related pathways, including apoptotic pathways that allow the host animals to detoxify reactive oxygen and nitrogen species that are generated by their intracellular photosynthetic symbionts, and determine the fate of corals under environmental stress. Some of these genes arose through horizontal gene transfer and comprise at least 0.2% of the animal gene inventory. Our analysis elucidates the evolutionary strategies that have allowed symbiotic corals to adapt and thrive for hundreds of millions of years. DOI:http://dx.doi.org/10.7554/eLife.13288.001 For millions of years, reef-building stony corals have created extensive habitats for numerous marine plants and animals in shallow tropical seas. Stony corals consist of many small, tentacled animals called polyps. These polyps secrete a mineral called aragonite to create the reef – an external ‘skeleton’ that supports and protects the corals. Photosynthesizing algae live inside the cells of stony corals, and each species depends on the other to survive. The algae produce the coral’s main source of food, although they also produce some waste products that can harm the coral if they build up inside cells. If the oceans become warmer and more acidic, the coral are more likely to become stressed and expel the algae from their cells in a process known as coral bleaching. This makes the coral more likely to die or become diseased. Corals have survived previous periods of ocean warming, although it is not known how they evolved to do so. The evolutionary history of an organism can be traced by studying its genome – its complete set of DNA – and the RNA molecules encoded by these genes. Bhattacharya et al. performed this analysis for twenty stony coral species, and compared the resulting genome and RNA sequences with the genomes of other related marine organisms, such as sea anemones and sponges. In particular, Bhattacharya et al. examined “ortholog” groups of genes, which are present in different species and evolved from a common ancestral gene. This analysis identified the genes in the corals that encode the proteins responsible for constructing the aragonite skeleton. The coral genome also encodes a network of environmental sensors that coordinate how the polyps respond to temperature, light and acidity. Bhattacharya et al. also uncovered a variety of stress-related pathways, including those that detoxify the polyps of the damaging molecules generated by algae, and the pathways that enable the polyps to adapt to environmental stress. Many of these genes were recruited from other species in a process known as horizontal gene transfer. The oceans are expected to become warmer and more acidic in the coming centuries. Provided that humans do not physically destroy the corals’ habitats, the evidence found by Bhattacharya et al. suggests that the genome of the corals contains the diversity that will allow them to adapt to these new conditions. DOI:http://dx.doi.org/10.7554/eLife.13288.002
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Affiliation(s)
- Debashish Bhattacharya
- Department of Ecology, Evolution and Natural Resources, Rutgers University, New Brunswick, United States.,Department of Marine and Coastal Sciences, Rutgers University, New Brunswick, United States
| | - Shobhit Agrawal
- Red Sea Research Center, Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Manuel Aranda
- Red Sea Research Center, Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Sebastian Baumgarten
- Red Sea Research Center, Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Mahdi Belcaid
- Hawaii Institute of Marine Biology, Kaneohe, United States
| | - Jeana L Drake
- Environmental Biophysics and Molecular Ecology Program, Department of Marine and Coastal Sciences, Rutgers University, New Brunswick, United States
| | - Douglas Erwin
- Smithsonian Institution, National Museum of Natural History, Washington, United States
| | - Sylvian Foret
- ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Australia.,Research School of Biology, Australian National University, Canberra, Australia
| | - Ruth D Gates
- Hawaii Institute of Marine Biology, Kaneohe, United States
| | - David F Gruber
- American Museum of Natural History, Sackler Institute for Comparative Genomics, New York, United States.,Department of Natural Sciences, City University of New York, Baruch College and The Graduate Center, New York, United States
| | - Bishoy Kamel
- Department of Biology, Mueller Lab, Penn State University, University Park, United States
| | - Michael P Lesser
- School of Marine Science and Ocean Engineering, University of New Hampshire, Durham, United States
| | - Oren Levy
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat Gam, Israel
| | - Yi Jin Liew
- Red Sea Research Center, Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Matthew MacManes
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, United States
| | - Tali Mass
- Environmental Biophysics and Molecular Ecology Program, Department of Marine and Coastal Sciences, Rutgers University, New Brunswick, United States.,Marine Biology Department, The Leon H. Charney School of Marine Sciences, University of Haifa, Mt. Carmel, Israel
| | - Monica Medina
- Department of Biology, Mueller Lab, Penn State University, University Park, United States
| | - Shaadi Mehr
- American Museum of Natural History, Sackler Institute for Comparative Genomics, New York, United States.,Biological Science Department, State University of New York, College at Old Westbury, New York, United States
| | - Eli Meyer
- Department of Integrative Biology, Oregon State University, Corvallis, United States
| | - Dana C Price
- Department of Plant Biology and Pathology, Rutgers University, New Brunswick, United States
| | | | - Huan Qiu
- Department of Ecology, Evolution and Natural Resources, Rutgers University, New Brunswick, United States
| | - Chuya Shinzato
- Marine Genomics Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
| | - Eiichi Shoguchi
- Marine Genomics Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
| | - Alexander J Stokes
- Laboratory of Experimental Medicine and Department of Cell and Molecular Biology, John A. Burns School of Medicine, Honolulu, United States.,Chaminade University, Honolulu, United States
| | | | - Dan Tchernov
- Marine Biology Department, The Leon H. Charney School of Marine Sciences, University of Haifa, Mt. Carmel, Israel
| | - Christian R Voolstra
- Red Sea Research Center, Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Nicole Wagner
- Department of Ecology, Evolution and Natural Resources, Rutgers University, New Brunswick, United States
| | - Charles W Walker
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, United States
| | - Andreas Pm Weber
- Institute of Plant Biochemistry, Heinrich-Heine-Universität, Düsseldorf, Germany
| | - Virginia Weis
- Department of Integrative Biology, Oregon State University, Corvallis, United States
| | - Ehud Zelzion
- Department of Ecology, Evolution and Natural Resources, Rutgers University, New Brunswick, United States
| | | | - Paul G Falkowski
- Environmental Biophysics and Molecular Ecology Program, Department of Marine and Coastal Sciences, Rutgers University, New Brunswick, United States.,Department of Earth and Planetary Sciences, Rutgers University, New Jersey, United States
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29
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Fondi M, Karkman A, Tamminen MV, Bosi E, Virta M, Fani R, Alm E, McInerney JO. "Every Gene Is Everywhere but the Environment Selects": Global Geolocalization of Gene Sharing in Environmental Samples through Network Analysis. Genome Biol Evol 2016; 8:1388-400. [PMID: 27190206 PMCID: PMC4898794 DOI: 10.1093/gbe/evw077] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The spatial distribution of microbes on our planet is famously formulated in the Baas Becking hypothesis as “everything is everywhere but the environment selects.” While this hypothesis does not strictly rule out patterns caused by geographical effects on ecology and historical founder effects, it does propose that the remarkable dispersal potential of microbes leads to distributions generally shaped by environmental factors rather than geographical distance. By constructing sequence similarity networks from uncultured environmental samples, we show that microbial gene pool distributions are not influenced nearly as much by geography as ecology, thus extending the Bass Becking hypothesis from whole organisms to microbial genes. We find that gene pools are shaped by their broad ecological niche (such as sea water, fresh water, host, and airborne). We find that freshwater habitats act as a gene exchange bridge between otherwise disconnected habitats. Finally, certain antibiotic resistance genes deviate from the general trend of habitat specificity by exhibiting a high degree of cross-habitat mobility. The strong cross-habitat mobility of antibiotic resistance genes is a cause for concern and provides a paradigmatic example of the rate by which genes colonize new habitats when new selective forces emerge.
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Affiliation(s)
- Marco Fondi
- Laboratory of Microbial and Molecular Evolution, Department of Biology, University of Florence, Italy Computational Biology Group, University of Florence, Italy
| | - Antti Karkman
- Department of Food and Environmental Sciences, University of Helsinki, Finland
| | - Manu V Tamminen
- Department of Environmental Systems Science, ETH Zürich, Switzerland Department of Aquatic Ecology, Eawag, Switzerland
| | - Emanuele Bosi
- Laboratory of Microbial and Molecular Evolution, Department of Biology, University of Florence, Italy Computational Biology Group, University of Florence, Italy
| | - Marko Virta
- Department of Food and Environmental Sciences, University of Helsinki, Finland
| | - Renato Fani
- Laboratory of Microbial and Molecular Evolution, Department of Biology, University of Florence, Italy Computational Biology Group, University of Florence, Italy
| | - Eric Alm
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology
| | - James O McInerney
- Department of Biology, National University of Ireland Maynooth, County Kildare, Ireland Computational Evolutionary Biology, Faculty of Life Sciences, The University of Manchester, United Kingdom
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30
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Suh A, Witt CC, Menger J, Sadanandan KR, Podsiadlowski L, Gerth M, Weigert A, McGuire JA, Mudge J, Edwards SV, Rheindt FE. Ancient horizontal transfers of retrotransposons between birds and ancestors of human pathogenic nematodes. Nat Commun 2016; 7:11396. [PMID: 27097561 PMCID: PMC4844689 DOI: 10.1038/ncomms11396] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 03/21/2016] [Indexed: 02/08/2023] Open
Abstract
Parasite host switches may trigger disease emergence, but prehistoric host ranges are often unknowable. Lymphatic filariasis and loiasis are major human diseases caused by the insect-borne filarial nematodes Brugia, Wuchereria and Loa. Here we show that the genomes of these nematodes and seven tropical bird lineages exclusively share a novel retrotransposon, AviRTE, resulting from horizontal transfer (HT). AviRTE subfamilies exhibit 83–99% nucleotide identity between genomes, and their phylogenetic distribution, paleobiogeography and invasion times suggest that HTs involved filarial nematodes. The HTs between bird and nematode genomes took place in two pantropical waves, >25–22 million years ago (Myr ago) involving the Brugia/Wuchereria lineage and >20–17 Myr ago involving the Loa lineage. Contrary to the expectation from the mammal-dominated host range of filarial nematodes, we hypothesize that these major human pathogens may have independently evolved from bird endoparasites that formerly infected the global breadth of avian biodiversity. Lymphatic filariasis and loiasis are diseases caused by insect-borne filarial nematodes. Here, Suh et al. identify a retrotransposon that is present in the genomes of these nematodes and seven tropical bird lineages, indicating two waves of horizontal gene transfer around 17–25 million years ago.
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Affiliation(s)
- Alexander Suh
- Department of Evolutionary Biology, Evolutionary Biology Centre (EBC), Uppsala University, SE-752 36 Uppsala, Sweden
| | - Christopher C Witt
- Department of Biology and Museum of Southwestern Biology, University of New Mexico, Albuquerque, New Mexico 87131, USA
| | - Juliana Menger
- Department of Conservation Biology, Helmholtz Centre for Environmental Research (UFZ), D-04318 Leipzig, Germany.,Molecular Evolution and Systematics of Animals, Institute of Biology, University of Leipzig, D-04103 Leipzig, Germany.,Instituto Nacional de Pesquisas da Amazônia (INPA), AM 69067-375 Manaus, Brazil
| | - Keren R Sadanandan
- Department of Biological Sciences, National University of Singapore, Singapore 117543, Singapore
| | - Lars Podsiadlowski
- Institute of Evolutionary Biology and Ecology, University of Bonn, D-53121 Bonn, Germany
| | - Michael Gerth
- Molecular Evolution and Systematics of Animals, Institute of Biology, University of Leipzig, D-04103 Leipzig, Germany
| | - Anne Weigert
- Molecular Evolution and Systematics of Animals, Institute of Biology, University of Leipzig, D-04103 Leipzig, Germany.,Max Planck Institute for Evolutionary Anthropology, D-04103 Leipzig, Germany
| | - Jimmy A McGuire
- Museum of Vertebrate Zoology and Department of Integrative Biology, University of California, Berkeley, Berkeley, California 94720, USA
| | - Joann Mudge
- National Center for Genome Resources, Santa Fe, New Mexico 87505, USA
| | - Scott V Edwards
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Frank E Rheindt
- Department of Biological Sciences, National University of Singapore, Singapore 117543, Singapore
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31
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Network-Thinking: Graphs to Analyze Microbial Complexity and Evolution. Trends Microbiol 2016; 24:224-237. [PMID: 26774999 PMCID: PMC4766943 DOI: 10.1016/j.tim.2015.12.003] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Revised: 12/02/2015] [Accepted: 12/08/2015] [Indexed: 01/23/2023]
Abstract
The tree model and tree-based methods have played a major, fruitful role in evolutionary studies. However, with the increasing realization of the quantitative and qualitative importance of reticulate evolutionary processes, affecting all levels of biological organization, complementary network-based models and methods are now flourishing, inviting evolutionary biology to experience a network-thinking era. We show how relatively recent comers in this field of study, that is, sequence-similarity networks, genome networks, and gene families–genomes bipartite graphs, already allow for a significantly enhanced usage of molecular datasets in comparative studies. Analyses of these networks provide tools for tackling a multitude of complex phenomena, including the evolution of gene transfer, composite genes and genomes, evolutionary transitions, and holobionts. Introgressive processes shape the microbial world at all levels of organisation. This reticulated evolution is increasingly studied by sequence-similarity networks. They provide an inclusive accurate multilevel framework to study the web of life. Networks enhance analyses of microbial genes, genomes, communities, and of symbiosis.
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Abstract
This paper considers whether multispecies biofilms are evolutionary individuals. Numerous multispecies biofilms have characteristics associated with individuality, such as internal integrity, division of labor, coordination among parts, and heritable adaptive traits. However, such multispecies biofilms often fail standard reproductive criteria for individuality: they lack reproductive bottlenecks, are comprised of multiple species, do not form unified reproductive lineages, and fail to have a significant division of reproductive labor among their parts. If such biofilms are good candidates for evolutionary individuals, then evolutionary individuality is achieved through other means than frequently cited reproductive processes. The case of multispecies biofilms suggests that standard reproductive requirements placed on individuality should be reconsidered. More generally, the case of multispecies biofilms indicates that accounts of individuality that focus on single-species eukaryotes are too restrictive and that a pluralistic and open-ended account of evolutionary individuality is needed.
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Affiliation(s)
- Marc Ereshefsky
- Department of Philosophy, University of Calgary, Calgary, AB, Canada T2N 1N4;
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Erwin DH. A public goods approach to major evolutionary innovations. GEOBIOLOGY 2015; 13:308-315. [PMID: 25867676 DOI: 10.1111/gbi.12137] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Accepted: 03/13/2015] [Indexed: 06/04/2023]
Abstract
The history of life is marked by a small number of major transitions, whether viewed from a genetic, ecological, or geological perspective. Specialists from various disciplines have focused on the packaging of information to generate new evolutionary individuals, on the expansion of ecological opportunity, or the abiotic drivers of environmental change to which organisms respond as the major drivers of these episodes. But the critical issue for understanding these major evolutionary transitions (METs) lies in the interactions between environmental, ecologic, and genetic change. Here, I propose that public goods may serve as one currency of such interactions: biological products that are non-excludable and non-rivalrous. Such biological public goods may be involved in either the generation of new evolutionary variation, as with genetic sequences that are easily transferred between different microbial lineages, or in the construction of new ecological niches, as with the progressive oxygenation of the oceans and atmosphere. Attention to public goods emphasizes the processes by which organisms actively construct their own evolutionary opportunities. Such public goods may have facilitated some METs.
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Affiliation(s)
- D H Erwin
- Department of Paleobiology, MRC-121, Smithsonian Institution, Washington, DC, USA
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Inter-phylum HGT has shaped the metabolism of many mesophilic and anaerobic bacteria. ISME JOURNAL 2015; 9:958-67. [PMID: 25314320 DOI: 10.1038/ismej.2014.193] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Revised: 07/12/2014] [Accepted: 08/25/2014] [Indexed: 11/08/2022]
Abstract
Genome sequencing has revealed that horizontal gene transfer (HGT) is a major evolutionary process in bacteria. Although it is generally assumed that closely related organisms engage in genetic exchange more frequently than distantly related ones, the frequency of HGT among distantly related organisms and the effect of ecological relatedness on the frequency has not been rigorously assessed. Here, we devised a novel bioinformatic pipeline, which minimized the effect of over-representation of specific taxa in the available databases and other limitations of homology-based approaches by analyzing genomes in standardized triplets, to quantify gene exchange between bacterial genomes representing different phyla. Our analysis revealed the existence of networks of genetic exchange between organisms with overlapping ecological niches, with mesophilic anaerobic organisms showing the highest frequency of exchange and engaging in HGT twice as frequently as their aerobic counterparts. Examination of individual cases suggested that inter-phylum HGT is more pronounced than previously thought, affecting up to ∼ 16% of the total genes and ∼ 35% of the metabolic genes in some genomes (conservative estimation). In contrast, ribosomal and other universal protein-coding genes were subjected to HGT at least 150 times less frequently than genes encoding the most promiscuous metabolic functions (for example, various dehydrogenases and ABC transport systems), suggesting that the species tree based on the former genes may be reliable. These results indicated that the metabolic diversity of microbial communities within most habitats has been largely assembled from preexisting genetic diversity through HGT and that HGT accounts for the functional redundancy among phyla.
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McInerney J, Cummins C, Haggerty L. Goods-thinking vs. tree-thinking: Finding a place for mobile genetic elements. Mob Genet Elements 2014; 1:304-308. [PMID: 22545244 PMCID: PMC3337142 DOI: 10.4161/mge.19153] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
While it has become increasingly clear that the Tree of Life hypothesis has limitations in its ability to describe the evolution of all evolving entities on the planet, there has been a marked reluctance to move away from the tree-based language. Ironically, while modifying the idea of the Tree of Life to the extent that it is only very distantly related to its original descriptions, there has been a very careful attempt to retain the language of tree-thinking. The recent movement away from a tree-thinking language toward a goods-thinking language and perspective is a significant improvement. In this commentary, we describe how goods-thinking can provide better descriptions of evolution, can integrate evolution with environment more closely and can offer an equal place for Mobile Genetic Elements and chromosomal elements in discussions of evolutionary history.
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Affiliation(s)
- James McInerney
- Bioinformatics and Molecular Evolution Unit; Department of Biology; National University of Ireland Maynooth, Co.; Kildare, Ireland
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36
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Liberles DA, Teufel AI, Liu L, Stadler T. On the need for mechanistic models in computational genomics and metagenomics. Genome Biol Evol 2014; 5:2008-18. [PMID: 24115604 PMCID: PMC3814209 DOI: 10.1093/gbe/evt151] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Computational genomics is now generating very large volumes of data that have the potential to be used to address important questions in both basic biology and biomedicine. Addressing these important biological questions becomes possible when mechanistic models rooted in biochemistry and evolutionary/population genetic processes are developed, instead of fitting data to off-the-shelf statistical distributions that do not enable mechanistic inference. Three examples are presented, the first involving ecological processes inferred from metagenomic data, the second involving mechanisms of gene regulation rooted in protein–DNA interactions with consideration of DNA structure, and the third involving existing models for the retention of duplicate genes that enables prediction of evolutionary mechanisms. This description of mechanistic models is generalized toward future developments in computational genomics and the need for biological mechanisms and processes in biological models.
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Bapteste E. The origins of microbial adaptations: how introgressive descent, egalitarian evolutionary transitions and expanded kin selection shape the network of life. Front Microbiol 2014; 5:83. [PMID: 24624128 PMCID: PMC3940903 DOI: 10.3389/fmicb.2014.00083] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Accepted: 02/16/2014] [Indexed: 11/20/2022] Open
Affiliation(s)
- Eric Bapteste
- UPMC, Institut de Biologie Paris Seine, UMR7138 'Evolution Paris Seine' Paris, France ; CNRS, Institut de Biologie Paris Seine, UMR7138 'Evolution Paris Seine' Paris, France
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Boon E, Meehan CJ, Whidden C, Wong DHJ, Langille MGI, Beiko RG. Interactions in the microbiome: communities of organisms and communities of genes. FEMS Microbiol Rev 2014; 38:90-118. [PMID: 23909933 PMCID: PMC4298764 DOI: 10.1111/1574-6976.12035] [Citation(s) in RCA: 119] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Revised: 07/02/2013] [Accepted: 07/10/2013] [Indexed: 12/17/2022] Open
Abstract
A central challenge in microbial community ecology is the delineation of appropriate units of biodiversity, which can be taxonomic, phylogenetic, or functional in nature. The term 'community' is applied ambiguously; in some cases, the term refers simply to a set of observed entities, while in other cases, it requires that these entities interact with one another. Microorganisms can rapidly gain and lose genes, potentially decoupling community roles from taxonomic and phylogenetic groupings. Trait-based approaches offer a useful alternative, but many traits can be defined based on gene functions, metabolic modules, and genomic properties, and the optimal set of traits to choose is often not obvious. An analysis that considers taxon assignment and traits in concert may be ideal, with the strengths of each approach offsetting the weaknesses of the other. Individual genes also merit consideration as entities in an ecological analysis, with characteristics such as diversity, turnover, and interactions modeled using genes rather than organisms as entities. We identify some promising avenues of research that are likely to yield a deeper understanding of microbial communities that shift from observation-based questions of 'Who is there?' and 'What are they doing?' to the mechanistically driven question of 'How will they respond?'
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Affiliation(s)
- Eva Boon
- Department of Biology, Dalhousie University, Halifax, NS, Canada
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Signatures of Natural Selection and Ecological Differentiation in Microbial Genomes. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 781:339-59. [DOI: 10.1007/978-94-007-7347-9_17] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
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40
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Kamneva OK, Ward NL. Reconciliation Approaches to Determining HGT, Duplications, and Losses in Gene Trees. METHODS IN MICROBIOLOGY 2014. [DOI: 10.1016/bs.mim.2014.08.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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41
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O'Malley MA. When integration fails: Prokaryote phylogeny and the tree of life. STUDIES IN HISTORY AND PHILOSOPHY OF BIOLOGICAL AND BIOMEDICAL SCIENCES 2013; 44:551-62. [PMID: 23137776 DOI: 10.1016/j.shpsc.2012.10.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Much is being written these days about integration, its desirability and even its necessity when complex research problems are to be addressed. Seldom, however, do we hear much about the failure of such efforts. Because integration is an ongoing activity rather than a final achievement, and because today's literature about integration consists mostly of manifesto statements rather than precise descriptions, an examination of unsuccessful integration could be illuminating to understand better how it works. This paper will examine the case of prokaryote phylogeny and its apparent failure to achieve integration within broader tree-of-life accounts of evolutionary history (often called 'universal phylogeny'). Despite the fact that integrated databases exist of molecules pertinent to the phylogenetic reconstruction of all lineages of life, and even though the same methods can be used to construct phylogenies wherever the organisms fall on the tree of life, prokaryote phylogeny remains at best only partly integrated within tree-of-life efforts. I will examine why integration does not occur, compare it with integrative practices in animal and other eukaryote phylogeny, and reflect on whether there might be different expectations of what integration should achieve. Finally, I will draw some general conclusions about integration and its function as a 'meta-heuristic' in the normative commitments guiding scientific practice.
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Affiliation(s)
- Maureen A O'Malley
- Department of Philosophy, University of Sydney, Quadrangle A14, NSW 2006, Australia.
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42
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Haggerty LS, Jachiet PA, Hanage WP, Fitzpatrick DA, Lopez P, O'Connell MJ, Pisani D, Wilkinson M, Bapteste E, McInerney JO. A pluralistic account of homology: adapting the models to the data. Mol Biol Evol 2013; 31:501-16. [PMID: 24273322 PMCID: PMC3935183 DOI: 10.1093/molbev/mst228] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Defining homologous genes is important in many evolutionary studies but raises obvious issues. Some of these issues are conceptual and stem from our assumptions of how a gene evolves, others are practical, and depend on the algorithmic decisions implemented in existing software. Therefore, to make progress in the study of homology, both ontological and epistemological questions must be considered. In particular, defining homologous genes cannot be solely addressed under the classic assumptions of strong tree thinking, according to which genes evolve in a strictly tree-like fashion of vertical descent and divergence and the problems of homology detection are primarily methodological. Gene homology could also be considered under a different perspective where genes evolve as “public goods,” subjected to various introgressive processes. In this latter case, defining homologous genes becomes a matter of designing models suited to the actual complexity of the data and how such complexity arises, rather than trying to fit genetic data to some a priori tree-like evolutionary model, a practice that inevitably results in the loss of much information. Here we show how important aspects of the problems raised by homology detection methods can be overcome when even more fundamental roots of these problems are addressed by analyzing public goods thinking evolutionary processes through which genes have frequently originated. This kind of thinking acknowledges distinct types of homologs, characterized by distinct patterns, in phylogenetic and nonphylogenetic unrooted or multirooted networks. In addition, we define “family resemblances” to include genes that are related through intermediate relatives, thereby placing notions of homology in the broader context of evolutionary relationships. We conclude by presenting some payoffs of adopting such a pluralistic account of homology and family relationship, which expands the scope of evolutionary analyses beyond the traditional, yet relatively narrow focus allowed by a strong tree-thinking view on gene evolution.
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Affiliation(s)
- Leanne S Haggerty
- Bioinformatics and Molecular Evolution Unit, Department of Biology, National University of Ireland Maynooth, Maynooth, Co. Kildare, Ireland
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43
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McInerney JO. More than tree dimensions: inter-lineage evolution's ecological importance. Trends Ecol Evol 2013; 28:624-5. [PMID: 24035465 DOI: 10.1016/j.tree.2013.09.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Revised: 09/01/2013] [Accepted: 09/03/2013] [Indexed: 10/26/2022]
Abstract
Horizontal transfer of genes has sometimes been viewed as a nuisance for the work of understanding the evolutionary history of lineages. Recent work has shown that clever analysis of inter-lineage gene transfer is productive and has tremendous explanatory power, in particular, for niche adaptation. These studies alter our perception of what are the fundamental units of evolution and selection.
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Affiliation(s)
- James O McInerney
- Department of Biology, National University of Ireland Maynooth, Co. Kildare, Ireland.
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EGN: a wizard for construction of gene and genome similarity networks. BMC Evol Biol 2013; 13:146. [PMID: 23841456 PMCID: PMC3727994 DOI: 10.1186/1471-2148-13-146] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2013] [Accepted: 07/05/2013] [Indexed: 01/11/2023] Open
Abstract
Background Increasingly, similarity networks are being used for evolutionary analyses of molecular datasets. These networks are very useful, in particular for the analysis of gene sharing, lateral gene transfer and for the detection of distant homologs. Currently, such analyses require some computer programming skills due to the limited availability of user-friendly freely distributed software. Consequently, although appealing, the construction and analyses of these networks remain less familiar to biologists than do phylogenetic approaches. Results In order to ease the use of similarity networks in the community of evolutionary biologists, we introduce a software program, EGN, that runs under Linux or MacOSX. EGN automates the reconstruction of gene and genome networks from nucleic and proteic sequences. EGN also implements statistics describing genetic diversity in these samples, for various user-defined thresholds of similarities. In the interest of studying the complexity of evolutionary processes affecting microbial evolution, we applied EGN to a dataset of 571,044 proteic sequences from the three domains of life and from mobile elements. We observed that, in Borrelia, plasmids play a different role than in most other eubacteria. Rather than being genetic couriers involved in lateral gene transfer, Borrelia’s plasmids and their genes act as private genetic goods, that contribute to the creation of genetic diversity within their parasitic hosts. Conclusion EGN can be used for constructing, analyzing, and mining molecular datasets in evolutionary studies. The program can help increase our knowledge of the processes through which genes from distinct sources and/or from multiple genomes co-evolve in lineages of cellular organisms.
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45
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Kamneva OK, Knight SJ, Liberles DA, Ward NL. Analysis of genome content evolution in pvc bacterial super-phylum: assessment of candidate genes associated with cellular organization and lifestyle. Genome Biol Evol 2013; 4:1375-90. [PMID: 23221607 PMCID: PMC3542564 DOI: 10.1093/gbe/evs113] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The Planctomycetes, Verrucomicrobia, Chlamydiae (PVC) super-phylum contains bacteria with either complex cellular organization or simple cell structure; it also includes organisms of different lifestyles (pathogens, mutualists, commensal, and free-living). Genome content evolution of this group has not been studied in a systematic fashion, which would reveal genes underlying the emergence of PVC-specific phenotypes. Here, we analyzed the evolutionary dynamics of 26 PVC genomes and several outgroup species. We inferred HGT, duplications, and losses by reconciliation of 27,123 gene trees with the species phylogeny. We showed that genome expansion and contraction have driven evolution within Planctomycetes and Chlamydiae, respectively, and balanced each other in Verrucomicrobia and Lentisphaerae. We also found that for a large number of genes in PVC genomes the most similar sequences are present in Acidobacteria, suggesting past and/or current ecological interaction between organisms from these groups. We also found evidence of shared ancestry between carbohydrate degradation genes in the mucin-degrading human intestinal commensal Akkermansia muciniphila and sequences from Acidobacteria and Bacteroidetes, suggesting that glycoside hydrolases are transferred laterally between gut microbes and that the process of carbohydrate degradation is crucial for microbial survival within the human digestive system. Further, we identified a highly conserved genetic module preferentially present in compartmentalized PVC species and possibly associated with the complex cell plan in these organisms. This conserved machinery is likely to be membrane targeted and involved in electron transport, although its exact function is unknown. These genes represent good candidates for future functional studies.
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Affiliation(s)
- Olga K Kamneva
- Department of Molecular Biology, University of Wyoming, WY, USA
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46
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Gene similarity networks provide tools for understanding eukaryote origins and evolution. Proc Natl Acad Sci U S A 2013; 110:E1594-603. [PMID: 23576716 DOI: 10.1073/pnas.1211371110] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The complexity and depth of the relationships between the three domains of life challenge the reliability of phylogenetic methods, encouraging the use of alternative analytical tools. We reconstructed a gene similarity network comprising the proteomes of 14 eukaryotes, 104 prokaryotes, 2,389 viruses and 1,044 plasmids. This network contains multiple signatures of the chimerical origin of Eukaryotes as a fusion of an archaebacterium and a eubacterium that could not have been observed using phylogenetic trees. A number of connected components (gene sets with stronger similarities than expected by chance) contain pairs of eukaryotic sequences exhibiting no direct detectable similarity. Instead, many eukaryotic sequences were indirectly connected through a "eukaryote-archaebacterium-eubacterium-eukaryote" similarity path. Furthermore, eukaryotic genes highly connected to prokaryotic genes from one domain tend not to be connected to genes from the other prokaryotic domain. Genes of archaebacterial and eubacterial ancestry tend to perform different functions and to act at different subcellular compartments, but in such an intertwined way that suggests an early rather than late integration of both gene repertoires. The archaebacterial repertoire has a similar size in all eukaryotic genomes whereas the number of eubacterium-derived genes is much more variable, suggesting a higher plasticity of this gene repertoire. Consequently, highly reduced eukaryotic genomes contain more genes of archaebacterial than eubacterial affinity. Connected components with prokaryotic and eukaryotic genes tend to include viral and plasmid genes, compatible with a role of gene mobility in the origin of Eukaryotes. Our analyses highlight the power of network approaches to study deep evolutionary events.
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Smith SE, Showers-Corneli P, Dardenne CN, Harpending HH, Martin DP, Beiko RG. Comparative genomic and phylogenetic approaches to characterize the role of genetic recombination in mycobacterial evolution. PLoS One 2012; 7:e50070. [PMID: 23189179 PMCID: PMC3506542 DOI: 10.1371/journal.pone.0050070] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2012] [Accepted: 10/19/2012] [Indexed: 02/01/2023] Open
Abstract
The genus Mycobacterium encompasses over one hundred named species of environmental and pathogenic organisms, including the causative agents of devastating human diseases such as tuberculosis and leprosy. The success of these human pathogens is due in part to their ability to rapidly adapt to their changing environment and host. Recombination is the fastest way for bacterial genomes to acquire genetic material, but conflicting results about the extent of recombination in the genus Mycobacterium have been reported. We examined a data set comprising 18 distinct strains from 13 named species for evidence of recombination. Genomic regions common to all strains (accounting for 10% to 22% of the full genomes of all examined species) were aligned and concatenated in the chromosomal order of one mycobacterial reference species. The concatenated sequence was screened for evidence of recombination using a variety of statistical methods, with each proposed event evaluated by comparing maximum-likelihood phylogenies of the recombinant section with the non-recombinant portion of the dataset. Incongruent phylogenies were identified by comparing the site-wise log-likelihoods of each tree using multiple tests. We also used a phylogenomic approach to identify genes that may have been acquired through horizontal transfer from non-mycobacterial sources. The most frequent associated lineages (and potential gene transfer partners) in the Mycobacterium lineage-restricted gene trees are other members of suborder Corynebacterinae, but more-distant partners were identified as well. In two examined cases of potentially frequent and habitat-directed transfer (M. abscessus to Segniliparus and M. smegmatis to Streptomyces), observed sequence distances were small and consistent with a hypothesis of transfer, while in a third case (M. vanbaalenii to Streptomyces) distances were larger. The analyses described here indicate that whereas evidence of recombination in core regions within the genus is relatively sparse, the acquisition of genes from non-mycobacterial lineages is a significant feature of mycobacterial evolution.
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Affiliation(s)
- Silvia E. Smith
- School of Medicine, Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, Utah, United States of America
- Department of Anthropology, University of Utah, Salt Lake City, Utah, United States of America
| | | | - Caitlin N. Dardenne
- School of Medicine, Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, Utah, United States of America
- Department of Anthropology, University of Utah, Salt Lake City, Utah, United States of America
| | - Henry H. Harpending
- Department of Anthropology, University of Utah, Salt Lake City, Utah, United States of America
| | - Darren P. Martin
- Computational Biology Group, Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, South Africa
| | - Robert G. Beiko
- Faculty of Computer Science, Dalhousie University, Halifax, Nova Scotia, Canada
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48
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Lang AS, Zhaxybayeva O, Beatty JT. Gene transfer agents: phage-like elements of genetic exchange. Nat Rev Microbiol 2012; 10:472-82. [PMID: 22683880 DOI: 10.1038/nrmicro2802] [Citation(s) in RCA: 254] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Horizontal gene transfer is important in the evolution of bacterial and archaeal genomes. An interesting genetic exchange process is carried out by diverse phage-like gene transfer agents (GTAs) that are found in a wide range of prokaryotes. Although GTAs resemble phages, they lack the hallmark capabilities that define typical phages, and they package random pieces of the producing cell's genome. In this Review, we discuss the defining characteristics of the GTAs that have been identified to date, along with potential functions for these agents and the possible evolutionary forces that act on the genes involved in their production.
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Affiliation(s)
- Andrew S Lang
- Department of Biology, Memorial University, St. John's, Newfoundland and Labrador A1B 3X9, Canada.
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49
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Thiergart T, Landan G, Schenk M, Dagan T, Martin WF. An evolutionary network of genes present in the eukaryote common ancestor polls genomes on eukaryotic and mitochondrial origin. Genome Biol Evol 2012; 4:466-85. [PMID: 22355196 PMCID: PMC3342870 DOI: 10.1093/gbe/evs018] [Citation(s) in RCA: 102] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
To test the predictions of competing and mutually exclusive hypotheses for the origin of eukaryotes, we identified from a sample of 27 sequenced eukaryotic and 994 sequenced prokaryotic genomes 571 genes that were present in the eukaryote common ancestor and that have homologues among eubacterial and archaebacterial genomes. Maximum-likelihood trees identified the prokaryotic genomes that most frequently contained genes branching as the sister to the eukaryotic nuclear homologues. Among the archaebacteria, euryarchaeote genomes most frequently harbored the sister to the eukaryotic nuclear gene, whereas among eubacteria, the α-proteobacteria were most frequently represented within the sister group. Only 3 genes out of 571 gave a 3-domain tree. Homologues from α-proteobacterial genomes that branched as the sister to nuclear genes were found more frequently in genomes of facultatively anaerobic members of the rhiozobiales and rhodospirilliales than in obligate intracellular ricketttsial parasites. Following α-proteobacteria, the most frequent eubacterial sister lineages were γ-proteobacteria, δ-proteobacteria, and firmicutes, which were also the prokaryote genomes least frequently found as monophyletic groups in our trees. Although all 22 higher prokaryotic taxa sampled (crenarchaeotes, γ-proteobacteria, spirochaetes, chlamydias, etc.) harbor genes that branch as the sister to homologues present in the eukaryotic common ancestor, that is not evidence of 22 different prokaryotic cells participating at eukaryote origins because prokaryotic “lineages” have laterally acquired genes for more than 1.5 billion years since eukaryote origins. The data underscore the archaebacterial (host) nature of the eukaryotic informational genes and the eubacterial (mitochondrial) nature of eukaryotic energy metabolism. The network linking genes of the eukaryote ancestor to contemporary homologues distributed across prokaryotic genomes elucidates eukaryote gene origins in a dialect cognizant of gene transfer in nature.
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Affiliation(s)
- Thorsten Thiergart
- Institute of Molecular Evolution, Heinrich-Heine University Düsseldorf, Germany
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