1
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van der Gulik PTS, Hoff WD, Speijer D. The contours of evolution: In defence of Darwin's tree of life paradigm. Bioessays 2024; 46:e2400012. [PMID: 38436469 DOI: 10.1002/bies.202400012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Revised: 02/12/2024] [Accepted: 02/15/2024] [Indexed: 03/05/2024]
Abstract
Both the concept of a Darwinian tree of life (TOL) and the possibility of its accurate reconstruction have been much criticized. Criticisms mostly revolve around the extensive occurrence of lateral gene transfer (LGT), instances of uptake of complete organisms to become organelles (with the associated subsequent gene transfer to the nucleus), as well as the implications of more subtle aspects of the biological species concept. Here we argue that none of these criticisms are sufficient to abandon the valuable TOL concept and the biological realities it captures. Especially important is the need to conceptually distinguish between organismal trees and gene trees, which necessitates incorporating insights of widely occurring LGT into modern evolutionary theory. We demonstrate that all criticisms, while based on important new findings, do not invalidate the TOL. After considering the implications of these new insights, we find that the contours of evolution are best represented by a TOL.
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Affiliation(s)
| | - Wouter D Hoff
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, Oklahoma, USA
| | - Dave Speijer
- Department of Medical Biochemistry, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
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2
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Gàlvez-Morante A, Guéguen L, Natsidis P, Telford MJ, Richter DJ. Dollo Parsimony Overestimates Ancestral Gene Content Reconstructions. Genome Biol Evol 2024; 16:evae062. [PMID: 38518756 PMCID: PMC10995720 DOI: 10.1093/gbe/evae062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Revised: 03/15/2024] [Accepted: 03/19/2024] [Indexed: 03/24/2024] Open
Abstract
Ancestral reconstruction is a widely used technique that has been applied to understand the evolutionary history of gain and loss of gene families. Ancestral gene content can be reconstructed via different phylogenetic methods, but many current and previous studies employ Dollo parsimony. We hypothesize that Dollo parsimony is not appropriate for ancestral gene content reconstruction inferences based on sequence homology, as Dollo parsimony is derived from the assumption that a complex character cannot be regained. This premise does not accurately model molecular sequence evolution, in which false orthology can result from sequence convergence or lateral gene transfer. The aim of this study is to test Dollo parsimony's suitability for ancestral gene content reconstruction and to compare its inferences with a maximum likelihood-based approach that allows a gene family to be gained more than once within a tree. We first compared the performance of the two approaches on a series of artificial data sets each of 5,000 genes that were simulated according to a spectrum of evolutionary rates without gene gain or loss, so that inferred deviations from the true gene count would arise only from errors in orthology inference and ancestral reconstruction. Next, we reconstructed protein domain evolution on a phylogeny representing known eukaryotic diversity. We observed that Dollo parsimony produced numerous ancestral gene content overestimations, especially at nodes closer to the root of the tree. These observations led us to the conclusion that, confirming our hypothesis, Dollo parsimony is not an appropriate method for ancestral reconstruction studies based on sequence homology.
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Affiliation(s)
- Alex Gàlvez-Morante
- Institut de Biologia Evolutiva (CSIC-Universitat Pompeu Fabra), Barcelona 08003, Spain
| | - Laurent Guéguen
- LBBE, UMR 5558, CNRS, Université Claude Bernard Lyon 1, Villeurbanne 69622, France
| | - Paschalis Natsidis
- Centre for Life's Origins and Evolution, Department of Genetics, Evolution and Environment, University College London, London WC1E 6BT, UK
| | - Maximilian J Telford
- Centre for Life's Origins and Evolution, Department of Genetics, Evolution and Environment, University College London, London WC1E 6BT, UK
| | - Daniel J Richter
- Institut de Biologia Evolutiva (CSIC-Universitat Pompeu Fabra), Barcelona 08003, Spain
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3
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Pardo-De la Hoz CJ, Magain N, Piatkowski B, Cornet L, Dal Forno M, Carbone I, Miadlikowska J, Lutzoni F. Ancient Rapid Radiation Explains Most Conflicts Among Gene Trees and Well-Supported Phylogenomic Trees of Nostocalean Cyanobacteria. Syst Biol 2023; 72:694-712. [PMID: 36827095 DOI: 10.1093/sysbio/syad008] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 02/12/2023] [Accepted: 02/22/2023] [Indexed: 02/25/2023] Open
Abstract
Prokaryotic genomes are often considered to be mosaics of genes that do not necessarily share the same evolutionary history due to widespread horizontal gene transfers (HGTs). Consequently, representing evolutionary relationships of prokaryotes as bifurcating trees has long been controversial. However, studies reporting conflicts among gene trees derived from phylogenomic data sets have shown that these conflicts can be the result of artifacts or evolutionary processes other than HGT, such as incomplete lineage sorting, low phylogenetic signal, and systematic errors due to substitution model misspecification. Here, we present the results of an extensive exploration of phylogenetic conflicts in the cyanobacterial order Nostocales, for which previous studies have inferred strongly supported conflicting relationships when using different concatenated phylogenomic data sets. We found that most of these conflicts are concentrated in deep clusters of short internodes of the Nostocales phylogeny, where the great majority of individual genes have low resolving power. We then inferred phylogenetic networks to detect HGT events while also accounting for incomplete lineage sorting. Our results indicate that most conflicts among gene trees are likely due to incomplete lineage sorting linked to an ancient rapid radiation, rather than to HGTs. Moreover, the short internodes of this radiation fit the expectations of the anomaly zone, i.e., a region of the tree parameter space where a species tree is discordant with its most likely gene tree. We demonstrated that concatenation of different sets of loci can recover up to 17 distinct and well-supported relationships within the putative anomaly zone of Nostocales, corresponding to the observed conflicts among well-supported trees based on concatenated data sets from previous studies. Our findings highlight the important role of rapid radiations as a potential cause of strongly conflicting phylogenetic relationships when using phylogenomic data sets of bacteria. We propose that polytomies may be the most appropriate phylogenetic representation of these rapid radiations that are part of anomaly zones, especially when all possible genomic markers have been considered to infer these phylogenies. [Anomaly zone; bacteria; horizontal gene transfer; incomplete lineage sorting; Nostocales; phylogenomic conflict; rapid radiation; Rhizonema.].
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Affiliation(s)
| | - Nicolas Magain
- Evolution and Conservation Biology, InBioS Research Center, Université de Liège, Liège 4000, Belgium
| | - Bryan Piatkowski
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830, USA
| | - Luc Cornet
- Evolution and Conservation Biology, InBioS Research Center, Université de Liège, Liège 4000, Belgium
- BCCM/IHEM, Mycology and Aerobiology, Sciensano, Brussels, Belgium
| | | | - Ignazio Carbone
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC 27606, USA
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4
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Zarlenga D, Thompson P, Mitreva M, Rosa BA, Hoberg E. Horizontal gene transfer provides insights into the deep evolutionary history and biology of Trichinella. Food Waterborne Parasitol 2022; 27:e00155. [PMID: 35542181 PMCID: PMC9079694 DOI: 10.1016/j.fawpar.2022.e00155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 04/06/2022] [Accepted: 04/11/2022] [Indexed: 12/03/2022] Open
Abstract
Evolution involves temporal changes in the characteristics of a species that are subsequently propagated or rejected through natural selection. In the case of parasites, host switching also plays a prominent role in the evolutionary process. These changes are rooted in genetic variation and gene flow where genes may be deleted, mutated (sequence), duplicated, rearranged and/or translocated and then transmitted through vertical gene transfer. However, the introduction of new genes is not driven only by Mendelian inheritance and mutation but also by the introduction of DNA from outside a lineage in the form of horizontal gene transfer between donor and recipient organisms. Once introduced and integrated into the biology of the recipient, vertical inheritance then perpetuates the newly acquired genetic factor, where further functionality may involve co-option of what has become a pre-existing physiological capacity. Upon sequencing the Trichinella spiralis (Clade I) genome, a cyanate hydratase (cyanase) gene was identified that is common among bacteria, fungi, and plants, but rarely observed among other eukaryotes. The sequence of the Trichinella cyanase gene clusters with those derived from the Kingdom Plantae in contrast to the genes found in some Clade III and IV nematodes that cluster with cyanases of bacterial origin. Phylogenetic analyses suggest that the Trichinella cyanase was acquired during the Devonian period and independently from those of other nematodes. These data may help inform us of the deep evolutionary history and ecological connectivity of early ancestors within the lineage of contemporary Trichinella. Further, in many extant organisms, cyanate detoxification has been largely superseded by energy requirements for metabolism. Thus, deciphering the function of Trichinella cyanase may provide new avenues for treatment and control.
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Affiliation(s)
- Dante Zarlenga
- U.S. Department of Agriculture, Agricultural Research Service, Animal Parasitic Diseases Laboratory, B1180 BARC-East Beltsville, MD 20705, USA
| | - Peter Thompson
- U.S. Department of Agriculture, Agricultural Research Service, Animal Parasitic Diseases Laboratory, B1180 BARC-East Beltsville, MD 20705, USA
| | - Makedonka Mitreva
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
- McDonnel Genome Institute, Washington University in St. Louis, St. Louis, MO 63108, USA
| | - Bruce A. Rosa
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
- McDonnel Genome Institute, Washington University in St. Louis, St. Louis, MO 63108, USA
| | - Eric Hoberg
- Department of Biology and Museum of Southwestern Biology, University of New Mexico, Albuquerque, NM 87131, USA
- Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI 53706, USA
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5
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Cote-L’Heureux A, Maurer-Alcalá XX, Katz LA. Old genes in new places: A taxon-rich analysis of interdomain lateral gene transfer events. PLoS Genet 2022; 18:e1010239. [PMID: 35731825 PMCID: PMC9255765 DOI: 10.1371/journal.pgen.1010239] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 07/05/2022] [Accepted: 05/06/2022] [Indexed: 11/26/2022] Open
Abstract
Vertical inheritance is foundational to Darwinian evolution, but fails to explain major innovations such as the rapid spread of antibiotic resistance among bacteria and the origin of photosynthesis in eukaryotes. While lateral gene transfer (LGT) is recognized as an evolutionary force in prokaryotes, the role of LGT in eukaryotic evolution is less clear. With the exception of the transfer of genes from organelles to the nucleus, a process termed endosymbiotic gene transfer (EGT), the extent of interdomain transfer from prokaryotes to eukaryotes is highly debated. A common critique of studies of interdomain LGT is the reliance on the topology of single-gene trees that attempt to estimate more than one billion years of evolution. We take a more conservative approach by identifying cases in which a single clade of eukaryotes is found in an otherwise prokaryotic gene tree (i.e. exclusive presence). Starting with a taxon-rich dataset of over 13,600 gene families and passing data through several rounds of curation, we identify and categorize the function of 306 interdomain LGT events into diverse eukaryotes, including 189 putative EGTs, 52 LGTs into Opisthokonta (i.e. animals, fungi and their microbial relatives), and 42 LGTs nearly exclusive to anaerobic eukaryotes. To assess differential gene loss as an explanation for exclusive presence, we compare branch lengths within each LGT tree to a set of vertically-inherited genes subsampled to mimic gene loss (i.e. with the same taxonomic sampling) and consistently find shorter relative distance between eukaryotes and prokaryotes in LGT trees, a pattern inconsistent with gene loss. Our methods provide a framework for future studies of interdomain LGT and move the field closer to an understanding of how best to model the evolutionary history of eukaryotes.
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Affiliation(s)
- Auden Cote-L’Heureux
- Department of Biological Sciences, Smith College, Northampton, Massachusetts, United States of America
| | | | - Laura A. Katz
- Department of Biological Sciences, Smith College, Northampton, Massachusetts, United States of America
- Program in Organismic Biology and Evolution, University of Massachusetts Amherst, Amherst, Massachusetts, United States of America
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6
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Bansal MS. Deciphering Microbial Gene Family Evolution Using Duplication-Transfer-Loss Reconciliation and RANGER-DTL. Methods Mol Biol 2022; 2569:233-252. [PMID: 36083451 DOI: 10.1007/978-1-0716-2691-7_11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Phylogenetic reconciliation has emerged as a principled, highly effective technique for investigating the origin, spread, and evolutionary history of microbial gene families. Proper application of phylogenetic reconciliation requires a clear understanding of potential pitfalls and sources of error, and knowledge of the most effective reconciliation-based tools and protocols to use to maximize accuracy. In this book chapter, we provide a brief overview of Duplication-Transfer-Loss (DTL) reconciliation, the standard reconciliation model used to study microbial gene families and provide a step-by-step computational protocol to maximize the accuracy of DTL reconciliation and minimize false-positive evolutionary inferences.
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Affiliation(s)
- Mukul S Bansal
- Department of Computer Science & Engineering, University of Connecticut, Storrs, CT, USA.
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7
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Zhu Q, Mirarab S. Assembling a Reference Phylogenomic Tree of Bacteria and Archaea by Summarizing Many Gene Phylogenies. Methods Mol Biol 2022; 2569:137-165. [PMID: 36083447 DOI: 10.1007/978-1-0716-2691-7_7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Phylogenomics is the inference of phylogenetic trees based on multiple marker genes sampled in the genomes of interest. An important challenge in phylogenomics is the potential incongruence among the evolutionary histories of individual genes, which can be widespread in microorganisms due to the prevalence of horizontal gene transfer. This protocol introduces the procedures for building a phylogenetic tree of a large number of microbial genomes using a broad sampling of marker genes that are representative of whole-genome evolution. The protocol highlights the use of a gene tree summary method, which can effectively reconstruct the species tree while accounting for the topological conflicts among individual gene trees. The pipeline described in this protocol is scalable to tens of thousands of genomes while retaining high accuracy. We discussed multiple software tools, libraries, and scripts to enable convenient adoption of the protocol. The protocol is suitable for microbiology and microbiome studies based on public genomes and metagenomic data.
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Affiliation(s)
- Qiyun Zhu
- Biodesign Center for Fundamental and Applied Microbiomics, Arizona State University, Tempe, AZ, USA.
- School of Life Sciences, Arizona State University, Tempe, AZ, USA.
| | - Siavash Mirarab
- Department of Electrical and Computer Engineering, University of California San Diego, San Diego, CA, USA
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8
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Lateral Gene Transfer Mechanisms and Pan-genomes in Eukaryotes. Trends Parasitol 2020; 36:927-941. [DOI: 10.1016/j.pt.2020.07.014] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 07/20/2020] [Accepted: 07/20/2020] [Indexed: 02/06/2023]
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9
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Zhao JH, Guo HS. Trans-kingdom RNA interactions drive the evolutionary arms race between hosts and pathogens. Curr Opin Genet Dev 2019; 58-59:62-69. [PMID: 31472442 DOI: 10.1016/j.gde.2019.07.019] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 07/23/2019] [Accepted: 07/30/2019] [Indexed: 12/12/2022]
Abstract
Trans-kingdom RNA plays a key role in host-parasite interactions. Hosts export specific endogenous microRNAs (miRNAs) into pathogens to target pathogen virulence genes and inhibit their invasion. In addition, trans-kingdom sRNAs produced by parasites may function as RNA effectors to suppress host immunity. Here, we summarize recent, important findings regarding trans-kingdom RNA and focus on the roles of trans-kingdom RNA in driving an evolutionary arms race between host and pathogen. We suggest that trans-kingdom RNA is a new platform for such arms races. Furthermore, we conjecture that trans-kingdom RNA contributes to horizontal gene transfer (HGT) involved in host-pathogen interactions. In addition, we propose that trans-kingdom RNA exchange and RNA driven HGT can have a great impact on the evolutionary ecology of interacting species.
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Affiliation(s)
- Jian-Hua Zhao
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, 100101 Beijing, China
| | - Hui-Shan Guo
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, 100101 Beijing, China; CAS Center for Excellence in Biotic Interactions, University of the Chinese Academy of Sciences, 100049 Beijing, China.
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10
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Tarasenko TA, Tarasenko VI, Koulintchenko MV, Klimenko ES, Konstantinov YM. DNA Import into Plant Mitochondria: Complex Approach for in organello and in vivo Studies. BIOCHEMISTRY (MOSCOW) 2019; 84:817-828. [DOI: 10.1134/s0006297919070113] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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11
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Sleep NH. Geological and Geochemical Constraints on the Origin and Evolution of Life. ASTROBIOLOGY 2018; 18:1199-1219. [PMID: 30124324 DOI: 10.1089/ast.2017.1778] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The traditional tree of life from molecular biology with last universal common ancestor (LUCA) branching into bacteria and archaea (though fuzzy) is likely formally valid enough to be a basis for discussion of geological processes on the early Earth. Biologists infer likely properties of nodal organisms within the tree and, hence, the environment they inhabited. Geologists both vet tenuous trees and putative origin of life scenarios for geological and ecological reasonability and conversely infer geological information from trees. The latter approach is valuable as geologists have only weakly constrained the time when the Earth became habitable and the later time when life actually existed to the long interval between ∼4.5 and ∼3.85 Ga where no intact surface rocks are known. With regard to vetting, origin and early evolution hypotheses from molecular biology have recently centered on serpentinite settings in marine and alternatively land settings that are exposed to ultraviolet sunlight. The existence of these niches on the Hadean Earth is virtually certain. With regard to inferring geological environment from genomics, nodes on the tree of life can arise from true bottlenecks implied by the marine serpentinite origin scenario and by asteroid impact. Innovation of a very useful trait through a threshold allows the successful organism to quickly become very abundant and later root a large clade. The origin of life itself, that is, the initial Darwinian ancestor, the bacterial and archaeal roots as free-living cellular organisms that independently escaped hydrothermal chimneys above marine serpentinite or alternatively from shallow pore-water environments on land, the Selabacteria root with anoxygenic photosynthesis, and the Terrabacteria root colonizing land are attractive examples that predate the geological record. Conversely, geological reasoning presents likely events for appraisal by biologists. Asteroid impacts may have produced bottlenecks by decimating life. Thermophile roots of bacteria and archaea as well as a thermophile LUCA are attractive.
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Affiliation(s)
- Norman H Sleep
- Department of Geophysics, Stanford University , Stanford, California
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12
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Microbes involving in carcinogenesis; growing state of the art. Microb Pathog 2018; 125:1-6. [PMID: 30172904 DOI: 10.1016/j.micpath.2018.08.061] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Revised: 08/26/2018] [Accepted: 08/29/2018] [Indexed: 12/17/2022]
Abstract
Lateral gene transfer (LGT) has been demonstrated as a transfer process of novel genes between different species. LGT proceedings are occurring between microbes and plants, as well as between microbes and animals. New evidence demonstrates that bacterial insertional mutagenesis may occur in cancer cells. Due to the important role of genetic changes in the increase of cell proliferation and cancer development, we reviewed the effects of microbial-animal LGT in human oncogenesis. In addition, viral DNA can induce cancer development by random insertion into cancer-related genes or by inducing translocations. In conclusion, growing evidence shows the contribution of the microbial genome in cancer and autoimmune disease.
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13
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Leger MM, Eme L, Stairs CW, Roger AJ. Demystifying Eukaryote Lateral Gene Transfer (Response to Martin 2017 DOI: 10.1002/bies.201700115). Bioessays 2018; 40:e1700242. [DOI: 10.1002/bies.201700242] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Revised: 02/06/2018] [Indexed: 12/28/2022]
Affiliation(s)
- Michelle M. Leger
- Institute of Evolutionary Biology (CSIC-UPF); Pg. Marítim de la Barceloneta, Barcelona ES 08003 Spain
| | - Laura Eme
- Department of Cell and Molecular Biology; Science for Life Laboratory; Uppsala University; Box 596, Uppsala SE 751 25 Sweden
| | - Courtney W. Stairs
- Department of Cell and Molecular Biology; Science for Life Laboratory; Uppsala University; Box 596, Uppsala SE 751 25 Sweden
| | - Andrew J. Roger
- Centre for Comparative Genomics and Evolutionary Bioinformatics; Department of Biochemistry and Molecular Biology; Dalhousie University; P.O. Box 15000, Halifax CAN B3H 4R2 Nova Scotia Canada
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14
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Harish A, Kurland CG. Mitochondria are not captive bacteria. J Theor Biol 2017; 434:88-98. [PMID: 28754286 DOI: 10.1016/j.jtbi.2017.07.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2017] [Revised: 07/10/2017] [Accepted: 07/14/2017] [Indexed: 10/19/2022]
Abstract
Lynn Sagan's conjecture (1967) that three of the fundamental organelles observed in eukaryote cells, specifically mitochondria, plastids and flagella were once free-living primitive (prokaryotic) cells was accepted after considerable opposition. Even though the idea was swiftly refuted for the specific case of origins of flagella in eukaryotes, the symbiosis model in general was accepted for decades as a realistic hypothesis to describe the endosymbiotic origins of eukaryotes. However, a systematic analysis of the origins of the mitochondrial proteome based on empirical genome evolution models now indicates that 97% of modern mitochondrial protein domains as well their homologues in bacteria and archaea were present in the universal common ancestor (UCA) of the modern tree of life (ToL). These protein domains are universal modular building blocks of modern genes and genomes, each of which is identified by a unique tertiary structure and a specific biochemical function as well as a characteristic sequence profile. Further, phylogeny reconstructed from genome-scale evolution models reveals that Eukaryotes and Akaryotes (archaea and bacteria) descend independently from UCA. That is to say, Eukaryotes and Akaryotes are both primordial lineages that evolved in parallel. Finally, there is no indication of massive inter-lineage exchange of coding sequences during the descent of the two lineages. Accordingly, we suggest that the evolution of the mitochondrial proteome was autogenic (endogenic) and not endosymbiotic (exogenic).
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Affiliation(s)
- Ajith Harish
- Department of Cell and Molecular Biology, Section of Structural and Molecular Biology, Uppsala University, Uppsala, Sweden.
| | - Charles G Kurland
- Department of Biology, Section of Microbial Ecology, Lund University, Lund, Sweden.
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15
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Williams TA, Szöllősi GJ, Spang A, Foster PG, Heaps SE, Boussau B, Ettema TJG, Embley TM. Integrative modeling of gene and genome evolution roots the archaeal tree of life. Proc Natl Acad Sci U S A 2017; 114:E4602-E4611. [PMID: 28533395 PMCID: PMC5468678 DOI: 10.1073/pnas.1618463114] [Citation(s) in RCA: 146] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A root for the archaeal tree is essential for reconstructing the metabolism and ecology of early cells and for testing hypotheses that propose that the eukaryotic nuclear lineage originated from within the Archaea; however, published studies based on outgroup rooting disagree regarding the position of the archaeal root. Here we constructed a consensus unrooted archaeal topology using protein concatenation and a multigene supertree method based on 3,242 single gene trees, and then rooted this tree using a recently developed model of genome evolution. This model uses evidence from gene duplications, horizontal transfers, and gene losses contained in 31,236 archaeal gene families to identify the most likely root for the tree. Our analyses support the monophyly of DPANN (Diapherotrites, Parvarchaeota, Aenigmarchaeota, Nanoarchaeota, Nanohaloarchaea), a recently discovered cosmopolitan and genetically diverse lineage, and, in contrast to previous work, place the tree root between DPANN and all other Archaea. The sister group to DPANN comprises the Euryarchaeota and the TACK Archaea, including Lokiarchaeum, which our analyses suggest are monophyletic sister lineages. Metabolic reconstructions on the rooted tree suggest that early Archaea were anaerobes that may have had the ability to reduce CO2 to acetate via the Wood-Ljungdahl pathway. In contrast to proposals suggesting that genome reduction has been the predominant mode of archaeal evolution, our analyses infer a relatively small-genomed archaeal ancestor that subsequently increased in complexity via gene duplication and horizontal gene transfer.
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Affiliation(s)
- Tom A Williams
- School of Earth Sciences, University of Bristol, Bristol BS8 1TQ, United Kingdom;
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Gergely J Szöllősi
- MTA-ELTE Lendület Evolutionary Genomics Research Group, 1117 Budapest, Hungary
| | - Anja Spang
- Department of Cell and Molecular Biology, Science for Life Laboratory, Uppsala University, SE-75123 Uppsala, Sweden
| | - Peter G Foster
- Department of Life Sciences, Natural History Museum, London SW7 5BD, United Kingdom
| | - Sarah E Heaps
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom
- School of Mathematics & Statistics, Newcastle University, Newcastle upon Tyne NE1 7RU, United Kingdom
| | - Bastien Boussau
- Univ Lyon, Université Lyon 1, CNRS, Laboratoire de Biométrie et Biologie Evolutive UMR5558, F-69622 Villeurbanne, France
| | - Thijs J G Ettema
- Department of Cell and Molecular Biology, Science for Life Laboratory, Uppsala University, SE-75123 Uppsala, Sweden
| | - T Martin Embley
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom
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16
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Harish A, Kurland CG. Akaryotes and Eukaryotes are independent descendants of a universal common ancestor. Biochimie 2017; 138:168-183. [PMID: 28461155 DOI: 10.1016/j.biochi.2017.04.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Accepted: 04/25/2017] [Indexed: 11/29/2022]
Abstract
We reconstructed a global tree of life (ToL) with non-reversible and non-stationary models of genome evolution that root trees intrinsically. We implemented Bayesian model selection tests and compared the statistical support for four conflicting ToL hypotheses. We show that reconstructions obtained with a Bayesian implementation (Klopfstein et al., 2015) are consistent with reconstructions obtained with an empirical Sankoff parsimony (ESP) implementation (Harish et al., 2013). Both are based on the genome contents of coding sequences for protein domains (superfamilies) from hundreds of genomes. Thus, we conclude that the independent descent of Eukaryotes and Akaryotes (archaea and bacteria) from the universal common ancestor (UCA) is the most probable as well as the most parsimonious hypothesis for the evolutionary origins of extant genomes. Reconstructions of ancestral proteomes by both Bayesian and ESP methods suggest that at least 70% of unique domain-superfamilies known in extant species were present in the UCA. In addition, identification of a vast majority (96%) of the mitochondrial superfamilies in the UCA proteome precludes a symbiotic hypothesis for the origin of eukaryotes. Accordingly, neither the archaeal origin of eukaryotes nor the bacterial origin of mitochondria is supported by the data. The proteomic complexity of the UCA suggests that the evolution of cellular phenotypes in the two primordial lineages, Akaryotes and Eukaryotes, was driven largely by duplication of common superfamilies as well as by loss of unique superfamilies. Finally, innovation of novel superfamilies has played a surprisingly small role in the evolution of Akaryotes and only a marginal role in the evolution of Eukaryotes.
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Affiliation(s)
- Ajith Harish
- Department of Cell and Molecular Biology, Structural and Molecular Biology Program, Uppsala University, Uppsala, Sweden.
| | - Charles G Kurland
- Department of Biology, Microbial Ecology Program, Lund University, Lund, Sweden.
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17
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Matassi G. Horizontal gene transfer drives the evolution of Rh50 permeases in prokaryotes. BMC Evol Biol 2017; 17:2. [PMID: 28049420 PMCID: PMC5209957 DOI: 10.1186/s12862-016-0850-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Accepted: 12/09/2016] [Indexed: 01/22/2023] Open
Abstract
Background Rh50 proteins belong to the family of ammonia permeases together with their Amt/MEP homologs. Ammonia permeases increase the permeability of NH3/NH4+ across cell membranes and are believed to be involved in excretion of toxic ammonia and in the maintenance of pH homeostasis. RH50 genes are widespread in eukaryotes but absent in land plants and fungi, and remarkably rare in prokaryotes. The evolutionary history of RH50 genes in prokaryotes is just beginning to be unveiled. Results Here, a molecular phylogenetic approach suggests horizontal gene transfer (HGT) as a primary force driving the evolution and spread of RH50 among prokaryotes. In addition, the taxonomic distribution of the RH50 gene among prokaryotes turned out to be very narrow; a single-copy RH50 is present in the genome of only a small proportion of Bacteria, and, first evidence to date, in only three methanogens among Euryarchaea. The coexistence of RH50 and AMT in prokaryotes seems also a rare event. Finally, phylogenetic analyses were used to reconstruct the HGT network along which prokaryotic RH50 evolution has taken place. Conclusions The eukaryotic or bacterial “origin” of the RH50 gene remains unsolved. The RH50 prokaryotic HGT network suggests a preferential directionality of transfer from aerobic to anaerobic organisms. The observed HGT events between archaeal methanogens, anaerobic and aerobic ammonia-oxidizing bacteria suggest that syntrophic relationships play a major role in the structuring of the network, and point to oxygen minimum zones as an ecological niche that might be of crucial importance for HGT-driven evolution. Electronic supplementary material The online version of this article (doi:10.1186/s12862-016-0850-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Giorgio Matassi
- Dipartimento di Scienze Agro-alimentari, Ambientali e Animali (DI4A), Università di Udine, Via delle Scienze, 206-33100, Udine, Italy.
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18
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da Fonseca GC, de Oliveira LFV, de Morais GL, Abdelnor RV, Nepomuceno AL, Waterhouse PM, Farinelli L, Margis R. Unusual RNA plant virus integration in the soybean genome leads to the production of small RNAs. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2016; 246:62-69. [PMID: 26993236 DOI: 10.1016/j.plantsci.2016.01.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Revised: 12/15/2015] [Accepted: 01/29/2016] [Indexed: 05/07/2023]
Abstract
Horizontal gene transfer (HGT) is known to be a major force in genome evolution. The acquisition of genes from viruses by eukaryotic genomes is a well-studied example of HGT, including rare cases of non-retroviral RNA virus integration. The present study describes the integration of cucumber mosaic virus RNA-1 into soybean genome. After an initial metatranscriptomic analysis of small RNAs derived from soybean, the de novo assembly resulted a 3029-nt contig homologous to RNA-1. The integration of this sequence in the soybean genome was confirmed by DNA deep sequencing. The locus where the integration occurred harbors the full RNA-1 sequence followed by the partial sequence of an endogenous mRNA and another sequence of RNA-1 as an inverted repeat and allowing the formation of a hairpin structure. This region recombined into a retrotransposon located inside an exon of a soybean gene. The nucleotide similarity of the integrated sequence compared to other Cucumber mosaic virus sequences indicates that the integration event occurred recently. We described a rare event of non-retroviral RNA virus integration in soybean that leads to the production of a double-stranded RNA in a similar fashion to virus resistance RNAi plants.
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Affiliation(s)
- Guilherme Cordenonsi da Fonseca
- Centro de Biotecnologia, Programa de Pós-Graduação em Biologia Celular e Molecular, Universidade Federal do Rio Grande do Sul, RS, Brazil.
| | - Luiz Felipe Valter de Oliveira
- Departamento de Genética, Programa de Pós-Graduação em Genética e Biologia Molecular, Universidade Federal do Rio Grande do Sul, RS, Brazil
| | | | | | | | - Peter M Waterhouse
- Centre for Tropical Crops and Biocommodities, Queensland University of Technology, Brisbane, Queensland, Australia
| | | | - Rogerio Margis
- Centro de Biotecnologia, Programa de Pós-Graduação em Biologia Celular e Molecular, Universidade Federal do Rio Grande do Sul, RS, Brazil; Departamento de Genética, Programa de Pós-Graduação em Genética e Biologia Molecular, Universidade Federal do Rio Grande do Sul, RS, Brazil.
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19
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Fullmer MS, Soucy SM, Gogarten JP. The pan-genome as a shared genomic resource: mutual cheating, cooperation and the black queen hypothesis. Front Microbiol 2015; 6:728. [PMID: 26284032 PMCID: PMC4523029 DOI: 10.3389/fmicb.2015.00728] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Accepted: 07/03/2015] [Indexed: 11/13/2022] Open
Affiliation(s)
- Matthew S Fullmer
- Department of Molecular and Cell Biology, University of Connecticut Storrs, CT, USA
| | - Shannon M Soucy
- Department of Molecular and Cell Biology, University of Connecticut Storrs, CT, USA
| | - Johann Peter Gogarten
- Department of Molecular and Cell Biology, University of Connecticut Storrs, CT, USA ; Institute for Systems Genomics, University of Connecticut Storrs, CT, USA
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Hunsperger HM, Randhawa T, Cattolico RA. Extensive horizontal gene transfer, duplication, and loss of chlorophyll synthesis genes in the algae. BMC Evol Biol 2015; 15:16. [PMID: 25887237 PMCID: PMC4337275 DOI: 10.1186/s12862-015-0286-4] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Accepted: 01/15/2015] [Indexed: 11/10/2022] Open
Abstract
Background Two non-homologous, isofunctional enzymes catalyze the penultimate step of chlorophyll a synthesis in oxygenic photosynthetic organisms such as cyanobacteria, eukaryotic algae and land plants: the light-independent (LIPOR) and light-dependent (POR) protochlorophyllide oxidoreductases. Whereas the distribution of these enzymes in cyanobacteria and land plants is well understood, the presence, loss, duplication, and replacement of these genes have not been surveyed in the polyphyletic and remarkably diverse eukaryotic algal lineages. Results A phylogenetic reconstruction of the history of the POR enzyme (encoded by the por gene in nuclei) in eukaryotic algae reveals replacement and supplementation of ancestral por genes in several taxa with horizontally transferred por genes from other eukaryotic algae. For example, stramenopiles and haptophytes share por gene duplicates of prasinophytic origin, although their plastid ancestry predicts a rhodophytic por signal. Phylogenetically, stramenopile pors appear ancestral to those found in haptophytes, suggesting transfer from stramenopiles to haptophytes by either horizontal or endosymbiotic gene transfer. In dinoflagellates whose plastids have been replaced by those of a haptophyte or diatom, the ancestral por genes seem to have been lost whereas those of the new symbiotic partner are present. Furthermore, many chlorarachniophytes and peridinin-containing dinoflagellates possess por gene duplicates. In contrast to the retention, gain, and frequent duplication of algal por genes, the LIPOR gene complement (chloroplast-encoded chlL, chlN, and chlB genes) is often absent. LIPOR genes have been lost from haptophytes and potentially from the euglenid and chlorarachniophyte lineages. Within the chlorophytes, rhodophytes, cryptophytes, heterokonts, and chromerids, some taxa possess both POR and LIPOR genes while others lack LIPOR. The gradual process of LIPOR gene loss is evidenced in taxa possessing pseudogenes or partial LIPOR gene compliments. No horizontal transfer of LIPOR genes was detected. Conclusions We document a pattern of por gene acquisition and expansion as well as loss of LIPOR genes from many algal taxa, paralleling the presence of multiple por genes and lack of LIPOR genes in the angiosperms. These studies present an opportunity to compare the regulation and function of por gene families that have been acquired and expanded in patterns unique to each of various algal taxa. Electronic supplementary material The online version of this article (doi:10.1186/s12862-015-0286-4) contains supplementary material, which is available to authorized users.
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21
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Beck A, Divakar PK, Zhang N, Molina MC, Struwe L. Evidence of ancient horizontal gene transfer between fungi and the terrestrial alga Trebouxia. ORG DIVERS EVOL 2014. [DOI: 10.1007/s13127-014-0199-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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22
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Zhu Q, Kosoy M, Dittmar K. HGTector: an automated method facilitating genome-wide discovery of putative horizontal gene transfers. BMC Genomics 2014; 15:717. [PMID: 25159222 PMCID: PMC4155097 DOI: 10.1186/1471-2164-15-717] [Citation(s) in RCA: 95] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2014] [Accepted: 08/20/2014] [Indexed: 11/23/2022] Open
Abstract
Background First pass methods based on BLAST match are commonly used as an initial step to separate the different phylogenetic histories of genes in microbial genomes, and target putative horizontal gene transfer (HGT) events. This will continue to be necessary given the rapid growth of genomic data and the technical difficulties in conducting large-scale explicit phylogenetic analyses. However, these methods often produce misleading results due to their inability to resolve indirect phylogenetic links and their vulnerability to stochastic events. Results A new computational method of rapid, exhaustive and genome-wide detection of HGT was developed, featuring the systematic analysis of BLAST hit distribution patterns in the context of a priori defined hierarchical evolutionary categories. Genes that fall beyond a series of statistically determined thresholds are identified as not adhering to the typical vertical history of the organisms in question, but instead having a putative horizontal origin. Tests on simulated genomic data suggest that this approach effectively targets atypically distributed genes that are highly likely to be HGT-derived, and exhibits robust performance compared to conventional BLAST-based approaches. This method was further tested on real genomic datasets, including Rickettsia genomes, and was compared to previous studies. Results show consistency with currently employed categories of HGT prediction methods. In-depth analysis of both simulated and real genomic data suggests that the method is notably insensitive to stochastic events such as gene loss, rate variation and database error, which are common challenges to the current methodology. An automated pipeline was created to implement this approach and was made publicly available at: https://github.com/DittmarLab/HGTector. The program is versatile, easily deployed, has a low requirement for computational resources. Conclusions HGTector is an effective tool for initial or standalone large-scale discovery of candidate HGT-derived genes. Electronic supplementary material The online version of this article (doi:10.1186/1471-2164-15-717) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Qiyun Zhu
- Department of Biological Sciences, University at Buffalo, State University of New York, 109 Cooke Hall, Buffalo, NY 14260, USA.
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23
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Zhu Q, Kosoy M, Olival KJ, Dittmar K. Horizontal transfers and gene losses in the phospholipid pathway of bartonella reveal clues about early ecological niches. Genome Biol Evol 2014; 6:2156-69. [PMID: 25106622 PMCID: PMC4159011 DOI: 10.1093/gbe/evu169] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Bartonellae are mammalian pathogens vectored by blood-feeding arthropods. Although of increasing medical importance, little is known about their ecological past, and host associations are underexplored. Previous studies suggest an influence of horizontal gene transfers in ecological niche colonization by acquisition of host pathogenicity genes. We here expand these analyses to metabolic pathways of 28 Bartonella genomes, and experimentally explore the distribution of bartonellae in 21 species of blood-feeding arthropods. Across genomes, repeated gene losses and horizontal gains in the phospholipid pathway were found. The evolutionary timing of these patterns suggests functional consequences likely leading to an early intracellular lifestyle for stem bartonellae. Comparative phylogenomic analyses discover three independent lineage-specific reacquisitions of a core metabolic gene—NAD(P)H-dependent glycerol-3-phosphate dehydrogenase (gpsA)—from Gammaproteobacteria and Epsilonproteobacteria. Transferred genes are significantly closely related to invertebrate Arsenophonus-, and Serratia-like endosymbionts, and mammalian Helicobacter-like pathogens, supporting a cellular association with arthropods and mammals at the base of extant Bartonella spp. Our studies suggest that the horizontal reacquisitions had a key impact on bartonellae lineage specific ecological and functional evolution.
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Affiliation(s)
- Qiyun Zhu
- Department of Biological Sciences, University at Buffalo, State University of New York
| | - Michael Kosoy
- Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Foothills Research Campus, Fort Collins, Colorado
| | | | - Katharina Dittmar
- Department of Biological Sciences, University at Buffalo, State University of New York Graduate Program of Evolution, Ecology, and Behavior, University at Buffalo, State University of New York
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24
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Yang J, Grünewald S, Xu Y, Wan XF. Quartet-based methods to reconstruct phylogenetic networks. BMC SYSTEMS BIOLOGY 2014; 8:21. [PMID: 24555518 PMCID: PMC3941989 DOI: 10.1186/1752-0509-8-21] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/16/2013] [Accepted: 02/12/2014] [Indexed: 11/11/2022]
Abstract
BACKGROUND Phylogenetic networks are employed to visualize evolutionary relationships among a group of nucleotide sequences, genes or species when reticulate events like hybridization, recombination, reassortant and horizontal gene transfer are believed to be involved. In comparison to traditional distance-based methods, quartet-based methods consider more information in the reconstruction process and thus have the potential to be more accurate. RESULTS We introduce QuartetSuite, which includes a set of new quartet-based methods, namely QuartetS, QuartetA, and QuartetM, to reconstruct phylogenetic networks from nucleotide sequences. We tested their performances and compared them with other popular methods on two simulated nucleotide sequence data sets: one generated from a tree topology and the other from a complicated evolutionary history containing three reticulate events. We further validated these methods to two real data sets: a bacterial data set consisting of seven concatenated genes of 36 bacterial species and an influenza data set related to recently emerging H7N9 low pathogenic avian influenza viruses in China. CONCLUSION QuartetS, QuartetA, and QuartetM have the potential to accurately reconstruct evolutionary scenarios from simple branching trees to complicated networks containing many reticulate events. These methods could provide insights into the understanding of complicated biological evolutionary processes such as bacterial taxonomy and reassortant of influenza viruses.
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Affiliation(s)
- Jialiang Yang
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State
University, Mississippi State, MS 39762, USA
- Current Address: Department of Genetics and Genomic Sciences, Icahn School of
Medicine at Mount Sinai, New York, NY 10029, USA
| | - Stefan Grünewald
- CAS-MPG Partner Institute for Computational Biology, Key Laboratory of
Computational Biology, Shanghai Institutes for Biological Sciences, Chinese
Academy of Sciences, Shanghai 200031, China
| | - Yifei Xu
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State
University, Mississippi State, MS 39762, USA
| | - Xiu-Feng Wan
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State
University, Mississippi State, MS 39762, USA
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25
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Yue J, Sun G, Hu X, Huang J. The scale and evolutionary significance of horizontal gene transfer in the choanoflagellate Monosiga brevicollis. BMC Genomics 2013; 14:729. [PMID: 24156600 PMCID: PMC4046809 DOI: 10.1186/1471-2164-14-729] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2012] [Accepted: 10/17/2013] [Indexed: 12/29/2022] Open
Abstract
Background It is generally agreed that horizontal gene transfer (HGT) is common in phagotrophic protists. However, the overall scale of HGT and the cumulative impact of acquired genes on the evolution of these organisms remain largely unknown. Results Choanoflagellates are phagotrophs and the closest living relatives of animals. In this study, we performed phylogenomic analyses to investigate the scale of HGT and the evolutionary importance of horizontally acquired genes in the choanoflagellate Monosiga brevicollis. Our analyses identified 405 genes that are likely derived from algae and prokaryotes, accounting for approximately 4.4% of the Monosiga nuclear genome. Many of the horizontally acquired genes identified in Monosiga were probably acquired from food sources, rather than by endosymbiotic gene transfer (EGT) from obsolete endosymbionts or plastids. Of 193 genes identified in our analyses with functional information, 84 (43.5%) are involved in carbohydrate or amino acid metabolism, and 45 (23.3%) are transporters and/or involved in response to oxidative, osmotic, antibiotic, or heavy metal stresses. Some identified genes may also participate in biosynthesis of important metabolites such as vitamins C and K12, porphyrins and phospholipids. Conclusions Our results suggest that HGT is frequent in Monosiga brevicollis and might have contributed substantially to its adaptation and evolution. This finding also highlights the importance of HGT in the genome and organismal evolution of phagotrophic eukaryotes. Electronic supplementary material The online version of this article (doi:10.1186/1471-2164-14-729) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | | | | | - Jinling Huang
- Department of Biology, East Carolina University, Greenville, NC 27858, USA.
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Abstract
The significance of horizontal gene transfer (HGT) in eukaryotic evolution remains controversial. Although many eukaryotic genes are of bacterial origin, they are often interpreted as being derived from mitochondria or plastids. Because of their fixed gene pool and gene loss, however, mitochondria and plastids alone cannot adequately explain the presence of all, or even the majority, of bacterial genes in eukaryotes. Available data indicate that no insurmountable barrier to HGT exists, even in complex multicellular eukaryotes. In addition, the discovery of both recent and ancient HGT events in all major eukaryotic groups suggests that HGT has been a regular occurrence throughout the history of eukaryotic evolution. A model of HGT is proposed that suggests both unicellular and early developmental stages as likely entry points for foreign genes into multicellular eukaryotes.
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Affiliation(s)
- Jinling Huang
- Department of Biology, East Carolina University, Greenville, NC, USA; Key Laboratory of Biodiversity and Biogeography, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
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27
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Willson SJ. Reconstruction of certain phylogenetic networks from their tree-average distances. Bull Math Biol 2013; 75:1840-78. [PMID: 23864219 DOI: 10.1007/s11538-013-9872-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Accepted: 06/27/2013] [Indexed: 10/26/2022]
Abstract
Trees are commonly utilized to describe the evolutionary history of a collection of biological species, in which case the trees are called phylogenetic trees. Often these are reconstructed from data by making use of distances between extant species corresponding to the leaves of the tree. Because of increased recognition of the possibility of hybridization events, more attention is being given to the use of phylogenetic networks that are not necessarily trees. This paper describes the reconstruction of certain such networks from the tree-average distances between the leaves. For a certain class of phylogenetic networks, a polynomial-time method is presented to reconstruct the network from the tree-average distances. The method is proved to work if there is a single reticulation cycle.
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Affiliation(s)
- Stephen J Willson
- Department of Mathematics, Iowa State University, Ames, IA, 50011, USA,
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28
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Riley DR, Sieber KB, Robinson KM, White JR, Ganesan A, Nourbakhsh S, Dunning Hotopp JC. Bacteria-human somatic cell lateral gene transfer is enriched in cancer samples. PLoS Comput Biol 2013; 9:e1003107. [PMID: 23840181 PMCID: PMC3688693 DOI: 10.1371/journal.pcbi.1003107] [Citation(s) in RCA: 107] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Accepted: 05/01/2013] [Indexed: 12/14/2022] Open
Abstract
There are 10× more bacterial cells in our bodies from the microbiome than human cells. Viral DNA is known to integrate in the human genome, but the integration of bacterial DNA has not been described. Using publicly available sequence data from the human genome project, the 1000 Genomes Project, and The Cancer Genome Atlas (TCGA), we examined bacterial DNA integration into the human somatic genome. Here we present evidence that bacterial DNA integrates into the human somatic genome through an RNA intermediate, and that such integrations are detected more frequently in (a) tumors than normal samples, (b) RNA than DNA samples, and (c) the mitochondrial genome than the nuclear genome. Hundreds of thousands of paired reads support random integration of Acinetobacter-like DNA in the human mitochondrial genome in acute myeloid leukemia samples. Numerous read pairs across multiple stomach adenocarcinoma samples support specific integration of Pseudomonas-like DNA in the 5′-UTR and 3′-UTR of four proto-oncogenes that are up-regulated in their transcription, consistent with conversion to an oncogene. These data support our hypothesis that bacterial integrations occur in the human somatic genome and may play a role in carcinogenesis. We anticipate that the application of our approach to additional cancer genome projects will lead to the more frequent detection of bacterial DNA integrations in tumors that are in close proximity to the human microbiome. There are 10× more bacterial cells in the human body than there are human cells that are part of the human microbiome. Many of those bacteria are in constant, intimate contact with human cells. We sought to establish if bacterial cells insert their own DNA into the human genome. Such random mutations could cause disease in the same manner that mutagens like UV rays from the sun or chemicals in cigarettes induce mutations. We detected the integration of bacterial DNA in the human genome more readily in tumors than normal samples. In particular, extensive amounts of DNA with similarity to Acinetobacter DNA were fused to human mitochondrial DNA in acute myeloid leukemia samples. We also identified specific integrations of DNA with similarity to Pseudomonas DNA near the untranslated regulatory regions of four proto-oncogenes. This supports our hypothesis that bacterial integrations occur in the human somatic genome that may potentially play a role in carcinogenesis. Further study in this area may provide new avenues for cancer prevention.
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Affiliation(s)
- David R. Riley
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Karsten B. Sieber
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Kelly M. Robinson
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - James Robert White
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Ashwinkumar Ganesan
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- Computer Science and Electrical Engineering Department, University of Maryland Baltimore County, Baltimore, Maryland, United States of America
| | - Syrus Nourbakhsh
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- University of Maryland College Park, College Park, Maryland, United States of America
| | - Julie C. Dunning Hotopp
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- Greenebaum Cancer Center, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- * E-mail:
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Redrejo-Rodríguez M, Muñoz-Espín D, Holguera I, Mencía M, Salas M. Nuclear localization signals in phage terminal proteins provide a novel gene delivery tool in mammalian cells. Commun Integr Biol 2013; 6:e22829. [PMID: 23750294 PMCID: PMC3609834 DOI: 10.4161/cib.22829] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Accepted: 11/08/2012] [Indexed: 11/21/2022] Open
Abstract
Terminal proteins (TPs) of bacteriophages prime DNA replication and become covalently linked to the genome ends. Unexpectedly, we have found functional eukaryotic nuclear localization signals (NLSs) within the TP sequences of bacteriophages from diverse families and hosts. Given the role of bacteriophages as vehicles for horizontal gene transfer (HGT), we postulated that viral genomes that have covalently linked NLS-containing terminal proteins might behave as vectors for HGT between bacteria and the eukaryotic nucleus. To validate this hypothesis, we profited from the in vitro Φ29 amplification system that allows the amplification of heterologous DNAs producing linear molecules of DNA with TP covalently attached to both 5' ends. Interestingly, these in vitro-generated TP-DNA molecules showed enhanced gene delivery in mammalian cells, supporting a possible role in HGT by transferring genes between prokaryotes and eukaryotes. Moreover, these TP-DNA molecules are a useful tool to amplify and subsequently deliver genes efficiently into the eukaryotic nucleus. Here, we suggest various possible applications and further developments of the technique with biotechnological and therapeutic purposes.
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Yang J, Grünewald S, Wan XF. Quartet-net: a quartet-based method to reconstruct phylogenetic networks. Mol Biol Evol 2013; 30:1206-17. [PMID: 23493256 DOI: 10.1093/molbev/mst040] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Phylogenetic networks can model reticulate evolutionary events such as hybridization, recombination, and horizontal gene transfer. However, reconstructing such networks is not trivial. Popular character-based methods are computationally inefficient, whereas distance-based methods cannot guarantee reconstruction accuracy because pairwise genetic distances only reflect partial information about a reticulate phylogeny. To balance accuracy and computational efficiency, here we introduce a quartet-based method to construct a phylogenetic network from a multiple sequence alignment. Unlike distances that only reflect the relationship between a pair of taxa, quartets contain information on the relationships among four taxa; these quartets provide adequate capacity to infer a more accurate phylogenetic network. In applications to simulated and biological data sets, we demonstrate that this novel method is robust and effective in reconstructing reticulate evolutionary events and it has the potential to infer more accurate phylogenetic distances than other conventional phylogenetic network construction methods such as Neighbor-Joining, Neighbor-Net, and Split Decomposition. This method can be used in constructing phylogenetic networks from simple evolutionary events involving a few reticulate events to complex evolutionary histories involving a large number of reticulate events. A software called "Quartet-Net" is implemented and available at http://sysbio.cvm.msstate.edu/QuartetNet/.
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Affiliation(s)
- Jialiang Yang
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, USA
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31
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Functional eukaryotic nuclear localization signals are widespread in terminal proteins of bacteriophages. Proc Natl Acad Sci U S A 2012; 109:18482-7. [PMID: 23091024 DOI: 10.1073/pnas.1216635109] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
A number of prokaryotic proteins have been shown to contain nuclear localization signals (NLSs), although its biological role remains sometimes unclear. Terminal proteins (TPs) of bacteriophages prime DNA replication and become covalently linked to the genome ends. We predicted NLSs within the TPs of bacteriophages from diverse families and hosts and, indeed, the TPs of Φ29, Nf, PRD1, Bam35, and Cp-1, out of seven TPs tested, were found to localize to the nucleus when expressed in mammalian cells. Detailed analysis of Φ29 TP led us to identify a bona fide NLS within residues 1-37. Importantly, gene delivery into the eukaryotic nucleus is enhanced by the presence of Φ29 TP attached to the 5' DNA ends. These findings show a common feature of TPs from diverse bacteriophages targeting the eukaryotic nucleus and suggest a possible common function by facilitating the horizontal transfer of genes between prokaryotes and eukaryotes.
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Lurie-Weinberger MN, Peeri M, Tuller T, Gophna U. Extensive Inter-Domain Lateral Gene Transfer in the Evolution of the Human Commensal Methanosphaera stadtmanae. Front Genet 2012; 3:182. [PMID: 23049536 PMCID: PMC3445992 DOI: 10.3389/fgene.2012.00182] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Accepted: 08/30/2012] [Indexed: 02/06/2023] Open
Abstract
Methanosphaera stadtmanae is a commensal methanogenic archaeon found in the human gut. As most of its niche-neighbors are bacteria, it is expected that lateral gene transfer (LGT) from bacteria might have contributed to the evolutionary history of this organism. We performed a phylogenomic survey of putative LGT events in M. stadtmanae, using a phylogenetic pipeline. Our analysis indicates that a substantial fraction of the proteins of M. stadtmanae are inferred to have been involved in inter-domain LGT. Laterally acquired genes have had a large contribution to surface functions, by providing novel glycosyltransferase functions. In addition, several ABC transporters seem to be of bacterial origin, including the molybdate transporter. Thus, bacterial genes contributed to the adaptation of M. stadtmanae to a host-dependent lifestyle by allowing a larger variation in surface structures and increasing transport efficiency in the gut niche which is diverse and competitive.
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Affiliation(s)
- Mor Nadia Lurie-Weinberger
- Department of Molecular Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel Aviv University Tel Aviv, Israel
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Baumdicker F, Hess WR, Pfaffelhuber P. The infinitely many genes model for the distributed genome of bacteria. Genome Biol Evol 2012; 4:443-56. [PMID: 22357598 PMCID: PMC3342869 DOI: 10.1093/gbe/evs016] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The distributed genome hypothesis states that the gene pool of a bacterial taxon is much more complex than that found in a single individual genome. However, the possible fitness advantage, why such genomic diversity is maintained, whether this variation is largely adaptive or neutral, and why these distinct individuals can coexist, remains poorly understood. Here, we present the infinitely many genes (IMG) model, which is a quantitative, evolutionary model for the distributed genome. It is based on a genealogy of individual genomes and the possibility of gene gain (from an unbounded reservoir of novel genes, e.g., by horizontal gene transfer from distant taxa) and gene loss, for example, by pseudogenization and deletion of genes, during reproduction. By implementing these mechanisms, the IMG model differs from existing concepts for the distributed genome, which cannot differentiate between neutral evolution and adaptation as drivers of the observed genomic diversity. Using the IMG model, we tested whether the distributed genome of 22 full genomes of picocyanobacteria (Prochlorococcus and Synechococcus) shows signs of adaptation or neutrality. We calculated the effective population size of Prochlorococcus at 1.01 × 1011 and predicted 18 distinct clades for this population, only six of which have been isolated and cultured thus far. We predicted that the Prochlorococcus pangenome contains 57,792 genes and found that the evolution of the distributed genome of Prochlorococcus was possibly neutral, whereas that of Synechococcus and the combined sample shows a clear deviation from neutrality.
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Affiliation(s)
- Franz Baumdicker
- University of Freiburg, Center for Biosystems Analysis, Habsburgerstrasse 49, Germany
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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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Cuypers TD, Hogeweg P. Virtual genomes in flux: an interplay of neutrality and adaptability explains genome expansion and streamlining. Genome Biol Evol 2012; 4:212-29. [PMID: 22234601 PMCID: PMC3318439 DOI: 10.1093/gbe/evr141] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The picture that emerges from phylogenetic gene content reconstructions is that genomes evolve in a dynamic pattern of rapid expansion and gradual streamlining. Ancestral organisms have been estimated to possess remarkably rich gene complements, although gene loss is a driving force in subsequent lineage adaptation and diversification. Here, we study genome dynamics in a model of virtual cells evolving to maintain homeostasis. We observe a pattern of an initial rapid expansion of the genome and a prolonged phase of mutational load reduction. Generally, load reduction is achieved by the deletion of redundant genes, generating a streamlining pattern. Load reduction can also occur as a result of the generation of highly neutral genomic regions. These regions can expand and contract in a neutral fashion. Our study suggests that genome expansion and streamlining are generic patterns of evolving systems. We propose that the complex genotype to phenotype mapping in virtual cells as well as in their biological counterparts drives genome size dynamics, due to an emerging interplay between adaptation, neutrality, and evolvability.
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Affiliation(s)
- Thomas D Cuypers
- Department of Theoretical Biology and Bioinformatics, Utrecht University, Utrecht, The Netherlands.
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Building Synthetic Systems to Learn Nature’s Design Principles. EVOLUTIONARY SYSTEMS BIOLOGY 2012; 751:411-29. [DOI: 10.1007/978-1-4614-3567-9_19] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Dalquen DA, Anisimova M, Gonnet GH, Dessimoz C. ALF--a simulation framework for genome evolution. Mol Biol Evol 2011; 29:1115-23. [PMID: 22160766 PMCID: PMC3341827 DOI: 10.1093/molbev/msr268] [Citation(s) in RCA: 111] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
In computational evolutionary biology, verification and benchmarking is a challenging task because the evolutionary history of studied biological entities is usually not known. Computer programs for simulating sequence evolution in silico have shown to be viable test beds for the verification of newly developed methods and to compare different algorithms. However, current simulation packages tend to focus either on gene-level aspects of genome evolution such as character substitutions and insertions and deletions (indels) or on genome-level aspects such as genome rearrangement and speciation events. Here, we introduce Artificial Life Framework (ALF), which aims at simulating the entire range of evolutionary forces that act on genomes: nucleotide, codon, or amino acid substitution (under simple or mixture models), indels, GC-content amelioration, gene duplication, gene loss, gene fusion, gene fission, genome rearrangement, lateral gene transfer (LGT), or speciation. The other distinctive feature of ALF is its user-friendly yet powerful web interface. We illustrate the utility of ALF with two possible applications: 1) we reanalyze data from a study of selection after globin gene duplication and test the statistical significance of the original conclusions and 2) we demonstrate that LGT can dramatically decrease the accuracy of two well-established orthology inference methods. ALF is available as a stand-alone application or via a web interface at http://www.cbrg.ethz.ch/alf.
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Affiliation(s)
- Daniel A Dalquen
- Computational Biochemistry Research Group, Department of Computer Science, ETH Zurich, Universitätstrasse 6, Zürich, Switzerland.
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Boc A, Makarenkov V. Towards an accurate identification of mosaic genes and partial horizontal gene transfers. Nucleic Acids Res 2011; 39:e144. [PMID: 21917854 PMCID: PMC3241670 DOI: 10.1093/nar/gkr735] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Many bacteria and viruses adapt to varying environmental conditions through the acquisition of mosaic genes. A mosaic gene is composed of alternating sequence polymorphisms either belonging to the host original allele or derived from the integrated donor DNA. Often, the integrated sequence contains a selectable genetic marker (e.g. marker allowing for antibiotic resistance). An effective identification of mosaic genes and detection of corresponding partial horizontal gene transfers (HGTs) are among the most important challenges posed by evolutionary biology. We developed a method for detecting partial HGT events and related intragenic recombination giving rise to the formation of mosaic genes. A bootstrap procedure incorporated in our method is used to assess the support of each predicted partial gene transfer. The proposed method can be also applied to confirm or discard complete (i.e. traditional) horizontal gene transfers detected by any HGT inferring method. While working on a full-genome scale, the new method can be used to assess the level of mosaicism in the considered genomes as well as the rates of complete and partial HGT underlying their evolution.
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Affiliation(s)
- Alix Boc
- Département d'Informatique, Université du Québec à Montréal, CP 8888, Succursale Centre Ville, Montreal, QC, Canada H3C 3P8
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Horizontal gene transfer facilitated the evolution of plant parasitic mechanisms in the oomycetes. Proc Natl Acad Sci U S A 2011; 108:15258-63. [PMID: 21878562 DOI: 10.1073/pnas.1105100108] [Citation(s) in RCA: 156] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Horizontal gene transfer (HGT) can radically alter the genomes of microorganisms, providing the capacity to adapt to new lifestyles, environments, and hosts. However, the extent of HGT between eukaryotes is unclear. Using whole-genome, gene-by-gene phylogenetic analysis we demonstrate an extensive pattern of cross-kingdom HGT between fungi and oomycetes. Comparative genomics, including the de novo genome sequence of Hyphochytrium catenoides, a free-living sister of the oomycetes, shows that these transfers largely converge within the radiation of oomycetes that colonize plant tissues. The repertoire of HGTs includes a large number of putatively secreted proteins; for example, 7.6% of the secreted proteome of the sudden oak death parasite Phytophthora ramorum has been acquired from fungi by HGT. Transfers include gene products with the capacity to break down plant cell walls and acquire sugars, nucleic acids, nitrogen, and phosphate sources from the environment. Predicted HGTs also include proteins implicated in resisting plant defense mechanisms and effector proteins for attacking plant cells. These data are consistent with the hypothesis that some oomycetes became successful plant parasites by multiple acquisitions of genes from fungi.
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40
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Abstract
Fungi possess robust cell walls and do not engulf prey cells by phagotrophy. As a consequence they are thought to be relatively immune from the invasion of foreign genes. Nonetheless, a growing body of evidence suggests gene transfer has amended the metabolic networks of many fungal species.
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Affiliation(s)
- Thomas A Richards
- Department of Zoology, Natural History Museum London, Cromwell Road, London, SW7 5BD, UK.
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Bokhari H, Anwar M, Mirza HB, Gillevet PM. Evidences of lateral gene transfer between archaea and pathogenic bacteria. Bioinformation 2011; 6:293-6. [PMID: 21769188 PMCID: PMC3134775 DOI: 10.6026/97320630006293] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2011] [Accepted: 06/27/2011] [Indexed: 11/23/2022] Open
Abstract
Acquisition of new genetic material through horizontal gene transfer has been shown to be an important feature in the evolution of many pathogenic bacteria. Changes in the genetic repertoire, occurring through gene acquisition and deletion, are the major events underlying the emergence and evolution of bacterial pathogens. However, horizontal gene transfer across the domains i.e. archaea and bacteria is not so common. In this context, we explore events of horizontal gene transfer between archaea and bacteria. In order to determine whether the acquisition of archaeal genes by lateral gene transfer is an important feature in the evolutionary history of the pathogenic bacteria, we have developed a scheme of stepwise eliminations that identifies archaeal-like genes in various bacterial genomes. We report the presence of 9 genes of archaeal origin in the genomes of various bacteria, a subset of which is also unique to the pathogenic members and are not found in respective non-pathogenic counterparts. We believe that these genes, having been retained in the respective genomes through selective advantage, have key functions in the organism's biology and may play a role in pathogenesis.
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Affiliation(s)
- Habib Bokhari
- Department of Biosciences, COMSATS Institute of Information Technology, Chakshahzad Campus, Park road Islamabad, Pakistan
| | - Maryam Anwar
- Department of Biosciences, COMSATS Institute of Information Technology, Chakshahzad Campus, Park road Islamabad, Pakistan
| | - Hasan Bilal Mirza
- Centre for Advanced Studies in Telecommunication (CAST), COMSATS Institute of Information Technology, Chakshahzad Campus, Park road Islamabad, Pakistan
| | - Patrick Martin Gillevet
- Department of Environmental Sciences and Policy, George Mason University, Manassas, Virginia, USA
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Lateral acquisition of genes is affected by the friendliness of their products. Proc Natl Acad Sci U S A 2010; 108:343-8. [PMID: 21149709 DOI: 10.1073/pnas.1009775108] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A major factor in the evolution of microbial genomes is the lateral acquisition of genes that evolved under the functional constraints of other species. Integration of foreign genes into a genome that has different components and circuits poses an evolutionary challenge. Moreover, genes belonging to complex modules in the pretransfer species are unlikely to maintain their functionality when transferred alone to new species. Thus, it is widely accepted that lateral gene transfer favors proteins with only a few protein-protein interactions. The propensity of proteins to participate in protein-protein interactions can be assessed using computational methods that identify putative interaction sites on the protein. Here we report that laterally acquired proteins contain significantly more putative interaction sites than native proteins. Thus, genes encoding proteins with multiple protein-protein interactions may in fact be more prone to transfer than genes with fewer interactions. We suggest that these proteins have a greater chance of forming new interactions in new species, thus integrating into existing modules. These results reveal basic principles for the incorporation of novel genes into existing systems.
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Kloesges T, Popa O, Martin W, Dagan T. Networks of gene sharing among 329 proteobacterial genomes reveal differences in lateral gene transfer frequency at different phylogenetic depths. Mol Biol Evol 2010; 28:1057-74. [PMID: 21059789 PMCID: PMC3021791 DOI: 10.1093/molbev/msq297] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Lateral gene transfer (LGT) is an important mechanism of natural variation among prokaryotes. Over the full course of evolution, most or all of the genes resident in a given prokaryotic genome have been affected by LGT, yet the frequency of LGT can vary greatly across genes and across prokaryotic groups. The proteobacteria are among the most diverse of prokaryotic taxa. The prevalence of LGT in their genome evolution calls for the application of network-based methods instead of tree-based methods to investigate the relationships among these species. Here, we report networks that capture both vertical and horizontal components of evolutionary history among 1,207,272 proteins distributed across 329 sequenced proteobacterial genomes. The network of shared proteins reveals modularity structure that does not correspond to current classification schemes. On the basis of shared protein-coding genes, the five classes of proteobacteria fall into two main modules, one including the alpha-, delta-, and epsilonproteobacteria and the other including beta- and gammaproteobacteria. The first module is stable over different protein identity thresholds. The second shows more plasticity with regard to the sequence conservation of proteins sampled, with the gammaproteobacteria showing the most chameleon-like evolutionary characteristics within the present sample. Using a minimal lateral network approach, we compared LGT rates at different phylogenetic depths. In general, gene evolution by LGT within proteobacteria is very common. At least one LGT event was inferred to have occurred in at least 75% of the protein families. The average LGT rate at the species and class depth is about one LGT event per protein family, the rate doubling at the phylum level to an average of two LGT events per protein family. Hence, our results indicate that the rate of gene acquisition per protein family is similar at the level of species (by recombination) and at the level of classes (by LGT). The frequency of LGT per genome strongly depends on the species lifestyle, with endosymbionts showing far lower LGT frequencies than free-living species. Moreover, the nature of the transferred genes suggests that gene transfer in proteobacteria is frequently mediated by conjugation.
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Affiliation(s)
- Thorsten Kloesges
- Institute of Botany III, Heinrich-Heine University Düsseldorf, Düsseldorf, Germany
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46
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Eukaryotic genes of archaebacterial origin are more important than the more numerous eubacterial genes, irrespective of function. Proc Natl Acad Sci U S A 2010; 107:17252-5. [PMID: 20852068 DOI: 10.1073/pnas.1000265107] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The traditional tree of life shows eukaryotes as a distinct lineage of living things, but many studies have suggested that the first eukaryotic cells were chimeric, descended from both Eubacteria (through the mitochondrion) and Archaebacteria. Eukaryote nuclei thus contain genes of both eubacterial and archaebacterial origins, and these genes have different functions within eukaryotic cells. Here we report that archaebacterium-derived genes are significantly more likely to be essential to yeast viability, are more highly expressed, and are significantly more highly connected and more central in the yeast protein interaction network. These findings hold irrespective of whether the genes have an informational or operational function, so that many features of eukaryotic genes with prokaryotic homologs can be explained by their origin, rather than their function. Taken together, our results show that genes of archaebacterial origin are in some senses more important to yeast metabolism than genes of eubacterial origin. This importance reflects these genes' origin as the ancestral nuclear component of the eukaryotic genome.
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47
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Experimental evidences of pSym transfer in a native peanut-associated rhizobia. Microbiol Res 2010; 165:505-15. [DOI: 10.1016/j.micres.2009.08.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2009] [Revised: 08/11/2009] [Accepted: 08/16/2009] [Indexed: 11/19/2022]
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Omer S, Kovacs A, Mazor Y, Gophna U. Integration of a foreign gene into a native complex does not impair fitness in an experimental model of lateral gene transfer. Mol Biol Evol 2010; 27:2441-5. [PMID: 20554693 DOI: 10.1093/molbev/msq145] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Lateral gene transfer (LGT) is a central force in microbial evolution. The observation that genes encoding subunits of complexes exhibit relatively compatible phylogenies, suggesting vertical descent, can be explained by different evolutionary scenarios. On the one hand, the failure of a new gene product to correctly interact with preexisting protein subunits can make its acquisition neutral-a theory termed the "complexity hypothesis." On the other hand, foreign subunit-encoding genes may reduce the fitness of the new host by disrupting the stoichiometric balance between complex subunits, resulting in purifying selection against gene retention. We previously showed in a model LGT system that overexpression of an orthologous subunit was neutral due to lack of interaction with host subunits. Here, we examine a case where the foreign protein is more similar to its native orthologs, by expressing the RNA polymerase β subunit (RpoB) of Bacillus subtilis in Escherichia coli. The foreign subunit is shown by coimmunoprecipitation to interact with the host subunits, and to form novel, nonspecific interactions. Nevertheless, the host did not incur any fitness disadvantage, as measured by its growth. We conclude that LGT of complex subunits may be neutral even when the transferred subunit can integrate into the host complex and that this neutrality can be a fertile ground for selective forces once the environment changes.
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Affiliation(s)
- Shira Omer
- Department of Molecular Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
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Bohlin L, Göransson U, Alsmark C, Wedén C, Backlund A. Natural products in modern life science. PHYTOCHEMISTRY REVIEWS : PROCEEDINGS OF THE PHYTOCHEMICAL SOCIETY OF EUROPE 2010; 9:279-301. [PMID: 20700376 PMCID: PMC2912726 DOI: 10.1007/s11101-009-9160-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2009] [Accepted: 11/17/2009] [Indexed: 05/02/2023]
Abstract
With a realistic threat against biodiversity in rain forests and in the sea, a sustainable use of natural products is becoming more and more important. Basic research directed against different organisms in Nature could reveal unexpected insights into fundamental biological mechanisms but also new pharmaceutical or biotechnological possibilities of more immediate use. Many different strategies have been used prospecting the biodiversity of Earth in the search for novel structure-activity relationships, which has resulted in important discoveries in drug development. However, we believe that the development of multidisciplinary incentives will be necessary for a future successful exploration of Nature. With this aim, one way would be a modernization and renewal of a venerable proven interdisciplinary science, Pharmacognosy, which represents an integrated way of studying biological systems. This has been demonstrated based on an explanatory model where the different parts of the model are explained by our ongoing research. Anti-inflammatory natural products have been discovered based on ethnopharmacological observations, marine sponges in cold water have resulted in substances with ecological impact, combinatory strategy of ecology and chemistry has revealed new insights into the biodiversity of fungi, in depth studies of cyclic peptides (cyclotides) has created new possibilities for engineering of bioactive peptides, development of new strategies using phylogeny and chemography has resulted in new possibilities for navigating chemical and biological space, and using bioinformatic tools for understanding of lateral gene transfer could provide potential drug targets. A multidisciplinary subject like Pharmacognosy, one of several scientific disciplines bridging biology and chemistry with medicine, has a strategic position for studies of complex scientific questions based on observations in Nature. Furthermore, natural product research based on intriguing scientific questions in Nature can be of value to increase the attraction for young students in modern life science.
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Affiliation(s)
- Lars Bohlin
- Division of Pharmacognosy, Department of Medicinal Chemistry, Biomedical Centre, Uppsala University, Box 574, 751 23 Uppsala, Sweden
| | - Ulf Göransson
- Division of Pharmacognosy, Department of Medicinal Chemistry, Biomedical Centre, Uppsala University, Box 574, 751 23 Uppsala, Sweden
| | - Cecilia Alsmark
- Division of Pharmacognosy, Department of Medicinal Chemistry, Biomedical Centre, Uppsala University, Box 574, 751 23 Uppsala, Sweden
| | - Christina Wedén
- Division of Pharmacognosy, Department of Medicinal Chemistry, Biomedical Centre, Uppsala University, Box 574, 751 23 Uppsala, Sweden
| | - Anders Backlund
- Division of Pharmacognosy, Department of Medicinal Chemistry, Biomedical Centre, Uppsala University, Box 574, 751 23 Uppsala, Sweden
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50
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Mallet LV, Becq J, Deschavanne P. Whole genome evaluation of horizontal transfers in the pathogenic fungus Aspergillus fumigatus. BMC Genomics 2010; 11:171. [PMID: 20226043 PMCID: PMC2848249 DOI: 10.1186/1471-2164-11-171] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2010] [Accepted: 03/12/2010] [Indexed: 12/14/2022] Open
Abstract
Background Numerous cases of horizontal transfers (HTs) have been described for eukaryote genomes, but in contrast to prokaryote genomes, no whole genome evaluation of HTs has been carried out. This is mainly due to a lack of parametric methods specially designed to take the intrinsic heterogeneity of eukaryote genomes into account. We applied a simple and tested method based on local variations of genomic signatures to analyze the genome of the pathogenic fungus Aspergillus fumigatus. Results We detected 189 atypical regions containing 214 genes, accounting for about 1 Mb of DNA sequences. However, the fraction of atypical DNA detected was smaller than the average amount detected in the same conditions in prokaryote genomes (3.1% vs 5.6%). It appeared that about one third of these regions contained no annotated genes, a proportion far greater than in prokaryote genomes. When analyzing the origin of these HTs by comparing their signatures to a home made database of species signatures, 3 groups of donor species emerged: bacteria (40%), fungi (25%), and viruses (22%). It is to be noticed that though inter-domain exchanges are confirmed, we only put in evidence very few exchanges between eukaryotic kingdoms. Conclusions In conclusion, we demonstrated that HTs are not negligible in eukaryote genomes, bearing in mind that in our stringent conditions this amount is a floor value, though of a lesser extent than in prokaryote genomes. The biological mechanisms underlying those transfers remain to be elucidated as well as the biological functions of the transferred genes.
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Affiliation(s)
- Ludovic V Mallet
- Molécules thérapeutiques in silico (MTI), INSERM UMR-M 973, Université Paris Diderot-Paris 7, Bât Lamarck, 35 rue Hélène Brion, 75205 Paris Cedex 13, France
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