DOCSLIB.ORG

The Eukaryotic Tree of Life from a Global Phylogenomic Perspective

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Eukaryotic Tree of Life from a Global Phylogenomic Perspective Downloaded from http://cshperspectives.cshlp.org/ on September 23, 2021 - Published by Cold Spring Harbor Laboratory Press The Eukaryotic Tree of Life from a Global Phylogenomic Perspective Fabien Burki Canadian Institute for Advanced Research, Department of Botany, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada Correspondence: [email protected] Molecular phylogenetics has revolutionized our knowledge of the eukaryotic tree of life. With the advent of genomics, a new discipline of phylogenetics has emerged: phylogenom- ics. This method uses large alignments of tens to hundreds of genes to reconstruct evolution- ary histories. This approach has led to the resolution of ancient and contentious relationships, notably between the building blocks of the tree (the supergroups), and allowed to place in the tree enigmatic yet important protist lineages for understanding eukaryote evolution. Here, I discuss the pros and cons of phylogenomics and review the eukaryotic supergroups in light of earlier work that laid the foundation for the current view of the tree, including the position of the root. I conclude by presenting a picture of eukaryote evolution, summarizing the most recent progress in assembling the global tree. t is redundant to say that eukaryotes are di- ticellular organisms. Eukaryotes have occupied Iverse. Plants, animals, and fungi are the char- just about every ecological niche on Earth. ismatic representatives of the eukaryotic do- Some actively gather food from the environ- main of life, but this narrow view does not do ment, others use plastids (chloroplasts) to de- justice to the eukaryotic diversity. Microscop- rive energy from the light; many can adapt to ic eukaryotes, often unicellular and known as variable conditions by switching between auto- the protists, represent the bulk of most major trophy and the predatory consumption of prey groups, whereas multicellular lineages are con- by phagotrophy. Eukaryotes also show a great fined to small corners on the global tree of eu- deal of genomic variation (Lynch and Conery karyotes. If all eukaryotes possess structures 2003). Some amoebozoan protists, for instance, enclosed within intracellular membranes (the have the largest known genomes—more than organelles), an infinite variation of forms and 200 times larger than that of humans (Keeling feeding strategies has evolved since their origin. and Slamovits 2005). Conversely, microbial Eukaryotic cells can wander on their own, some- parasites can have highly compact, bacterial- times forming hordes of free-living pico-sized size genomes (Corradi et al. 2010). Even smaller organisms that flourish in oceans. They can be are the remnant nuclear genomes (nucleo- parasites or symbionts, or come together by the morphs) of what were once free-living microbi- billions in tightly packed, highly regulated mul- al algae. At around 500,000 nucleotides and Editors: Patrick J. Keeling and Eugene V. Koonin Additional Perspectives on The Origin and Evolution of Eukaryotes available at www.cshperspectives.org Copyright # 2014 Cold Spring Harbor Laboratory Press; all rights reserved; doi: 10.1101/cshperspect.a016147 Cite this article as Cold Spring Harb Perspect Biol 2014;6:a016147 1 Downloaded from http://cshperspectives.cshlp.org/ on September 23, 2021 - Published by Cold Spring Harbor Laboratory Press F. Burki hardly encoding a few hundreds genes, nucleo- easy to amplify and contains both hypervaria- morphs are the smallest nuclear genome of all ble and conserved regions, allowing researchers (Douglas et al. 2001; Gilson et al. 2006; Lane to investigate different depths of phylogenet- et al. 2007). ic resolution. As a result, the SSU rRNA domi- Recognizing this great diversity and pushed nates molecular databases, and the majority of by a desire to establish order, biologists have the known eukaryotic diversity, when character- long attempted to assemble a global eukaryotic ized molecularly, is still defined solely by this tree of life. A fully resolved phylogenetic tree marker. including all organisms is not only the ultimate The pioneering molecular phylogenies con- goal of systematics, it would also provide the sistently recovered a handful of deeply diverging foundation to infer the acquisition and evolu- protist lineages (e.g., diplomonads, parabasal- tion of countless characters through the history ids, microsporidians, Archamoebae), progres- of long-dead species. But early attempts to re- sively emerging from the distant prokaryot- solve the eukaryotic tree, most of which were ic root, and followed by a densely branched based on comparisons of morphology and nu- “crown,” nesting the more familiar eukaryotic trition modes, faced the impossible challenge diversity (Sogin et al. 1986, 1989; Friedman of describing in an evolutionary sensitive way et al. 1987; Woese et al. 1990; Sogin 1991). a world in which most of the diversity occurs This was an appealing picture of evolution be- among tiny microbes. For decades, biology text- cause these early diverging species were seem- books assigned the eukaryotes to evolutionary ingly morphologically simple single-cell organ- entities called “kingdoms” in which the lords isms that lacked mitochondria and other were the animals, plants, and fungi (Copeland typical eukaryotic structures, such as peroxi- 1938; Whittaker 1969; Margulis 1971). This is somes (Keeling 1998). These phylogenies were not to say that biologist ignored protists, and also consistent with the archezoa hypothesis, they have been in fact recognized as a kingdom which postulated that amitochondriate eukary- for more that a century (Haeckel 1866), but ote lineages diverged before the endosymbiotic protists were considered to be "simple" organ- event that gave rise to mitochondria (Cavalier- isms from which more elaborate, multicellular Smith 1983, 1987, 1989). Even more convincing species emerged. Although these early propos- was that other molecular markers, including als succeeded in recognizing several major as- various elongations factors and RNA polymer- semblages, such as animals and plants, they ase subunits, corroborated the deep-branching were less successful in resolving the relation- position of archezoan taxa, altogether sup- ships between the groups and, with the benefit porting the prediction that they should branch of hindsight, failed to account for the funda- earlier than the mitochondrion-containing mental paraphyletic and complex nature of eukaryotes if they predate the origin of this or- the protist lines. ganelle (Brown and Doolittle 1995; Klenk et al. 1995; Kamaishi et al. 1996; Yamamoto et al. 1997). A MOLECULAR (R)EVOLUTION At the other end of the tree, the so-called The backbone of the eukaryotic tree has gone crown, contain the major clades of eukaryotes, through some profound rearrangements in the appearing tightly bunched together as if they past 20 years. Comparing nucleotide or amino diverged almost simultaneously (Sogin 1991; acid sequences is now the tool of choice for re- Knoll 1992). These clades included animals, constructing evolutionary histories. This is par- fungi, and plants as well as diverse protist line- ticularly true for protists because the interpre- ages such as alveolates and stramenopiles (see tation of their morphological characters alone below). The branching pattern among the SSU is problematic. For years, the go-to molecular rRNA crown taxa, however, could not be re- marker for phylogenetics has been the small solved even with the help of several protein subunit ribosomal RNA (SSU rRNA). It is markers (Baldauf 1999; Hirt et al. 1999; Roger 2 Cite this article as Cold Spring Harb Perspect Biol 2014;6:a016147 Downloaded from http://cshperspectives.cshlp.org/ on September 23, 2021 - Published by Cold Spring Harbor Laboratory Press The Tree of Eukaryotes et al. 1999; Moreira et al. 2000). This lack of mo- karyotic crown, and no longer supported the lecular resolution was interpreted as evidence idea that the prokaryote-to-eukaryote transi- that not enough phylogenetic signal could accu- tion was a progressive transformation involving mulate in the sequences because most phyla intermediate amitochondriate forms. emerged in a very short period of time, like in More generally, the whole eukaryotic tree a “big-bang” explosion of species diversification was shaken up by important discrepancies be- (Philippe et al. 2000a,b). tween SSU rRNA-based phylogenies and those inferred from a growing number of protein- coding genes, as well as discrete molecular char- TRIMMING THE TREE acters such as shared indels (insertion/dele- The early molecular-based interpretation of tions) or gene fusions, or the systematic analysis the eukaryotic tree showing the archezoan- of light and electron microscopy data (e.g., Bal- crown dichotomy did not last very long. First, dauf and Palmer 1993; Keeling and Doolittle as more and more lineages were being se- 1996; Fast et al. 1999; Baldauf et al. 2000; Mo- quenced, mitochondriate protist groups such reira et al. 2000; Cavalier-Smith 2002; Simpson as Euglenozoa and Foraminifera squeezed in 2003; Nikolaev et al. 2004; Harper et al. 2005). between the archezoan taxa and the crown (So- The integration of these various kinds of data gin et al. 1986; Clark and Cross 1988; Pawlowski led to the conception that most, if not all, eu- et al. 1996). Moreover, the archezoans were karyotic diversity can be assigned to one of sev- characterized byelevated rates of molecular evo- eral major assemblages, called “supergroups” lution, which translates
Load more

Recommended publications
  • Basal Body Structure and Composition in the Apicomplexans Toxoplasma and Plasmodium Maria E
    Francia et al. Cilia (2016) 5:3 DOI 10.1186/s13630-016-0025-5 Cilia REVIEW Open Access Basal body structure and composition in the apicomplexans Toxoplasma and Plasmodium Maria E. Francia1* , Jean‑Francois Dubremetz2 and Naomi S. Morrissette3 Abstract The phylum Apicomplexa encompasses numerous important human and animal disease-causing parasites, includ‑ ing the Plasmodium species, and Toxoplasma gondii, causative agents of malaria and toxoplasmosis, respectively. Apicomplexans proliferate by asexual replication and can also undergo sexual recombination. Most life cycle stages of the parasite lack flagella; these structures only appear on male gametes. Although male gametes (microgametes) assemble a typical 9 2 axoneme, the structure of the templating basal body is poorly defined. Moreover, the rela‑ tionship between asexual+ stage centrioles and microgamete basal bodies remains unclear. While asexual stages of Plasmodium lack defined centriole structures, the asexual stages of Toxoplasma and closely related coccidian api‑ complexans contain centrioles that consist of nine singlet microtubules and a central tubule. There are relatively few ultra-structural images of Toxoplasma microgametes, which only develop in cat intestinal epithelium. Only a subset of these include sections through the basal body: to date, none have unambiguously captured organization of the basal body structure. Moreover, it is unclear whether this basal body is derived from pre-existing asexual stage centrioles or is synthesized de novo. Basal bodies in Plasmodium microgametes are thought to be synthesized de novo, and their assembly remains ill-defined. Apicomplexan genomes harbor genes encoding δ- and ε-tubulin homologs, potentially enabling these parasites to assemble a typical triplet basal body structure.
    [Show full text]
  • Molecular Data and the Evolutionary History of Dinoflagellates by Juan Fernando Saldarriaga Echavarria Diplom, Ruprecht-Karls-Un
    Molecular data and the evolutionary history of dinoflagellates by Juan Fernando Saldarriaga Echavarria Diplom, Ruprecht-Karls-Universitat Heidelberg, 1993 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY in THE FACULTY OF GRADUATE STUDIES Department of Botany We accept this thesis as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA November 2003 © Juan Fernando Saldarriaga Echavarria, 2003 ABSTRACT New sequences of ribosomal and protein genes were combined with available morphological and paleontological data to produce a phylogenetic framework for dinoflagellates. The evolutionary history of some of the major morphological features of the group was then investigated in the light of that framework. Phylogenetic trees of dinoflagellates based on the small subunit ribosomal RNA gene (SSU) are generally poorly resolved but include many well- supported clades, and while combined analyses of SSU and LSU (large subunit ribosomal RNA) improve the support for several nodes, they are still generally unsatisfactory. Protein-gene based trees lack the degree of species representation necessary for meaningful in-group phylogenetic analyses, but do provide important insights to the phylogenetic position of dinoflagellates as a whole and on the identity of their close relatives. Molecular data agree with paleontology in suggesting an early evolutionary radiation of the group, but whereas paleontological data include only taxa with fossilizable cysts, the new data examined here establish that this radiation event included all dinokaryotic lineages, including athecate forms. Plastids were lost and replaced many times in dinoflagellates, a situation entirely unique for this group. Histones could well have been lost earlier in the lineage than previously assumed.
    [Show full text]
  • Molecular Phylogenetic Position of Hexacontium Pachydermum Jørgensen (Radiolaria)
    Marine Micropaleontology 73 (2009) 129–134 Contents lists available at ScienceDirect Marine Micropaleontology journal homepage: www.elsevier.com/locate/marmicro Molecular phylogenetic position of Hexacontium pachydermum Jørgensen (Radiolaria) Tomoko Yuasa a,⁎, Jane K. Dolven b, Kjell R. Bjørklund b, Shigeki Mayama c, Osamu Takahashi a a Department of Astronomy and Earth Sciences, Tokyo Gakugei University, Koganei, Tokyo 184-8501, Japan b Natural History Museum, University of Oslo, P.O. Box 1172, Blindern, 0318 Oslo, Norway c Department of Biology, Tokyo Gakugei University, Koganei, Tokyo 184-8501, Japan article info abstract Article history: The taxonomic affiliation of Hexacontium pachydermum Jørgensen, specifically whether it belongs to the Received 9 April 2009 order Spumellarida or the order Entactinarida, is a subject of ongoing debate. In this study, we sequenced the Received in revised form 3 August 2009 18S rRNA gene of H. pachydermum and of three spherical spumellarians of Cladococcus viminalis Haeckel, Accepted 7 August 2009 Arachnosphaera myriacantha Haeckel, and Astrosphaera hexagonalis Haeckel. Our molecular phylogenetic analysis revealed that the spumellarian species of C. viminalis, A. myriacantha, and A. hexagonalis form a Keywords: monophyletic group. Moreover, this clade occupies a sister position to the clade comprising the spongodiscid Radiolaria fi Entactinarida spumellarians, coccodiscid spumellarians, and H. pachydermum. This nding is contrary to the results of Spumellarida morphological studies based on internal spicular morphology, placing H. pachydermum in the order Nassellarida Entactinarida, which had been considered to have a common ancestor shared with the nassellarians. 18S rRNA gene © 2009 Elsevier B.V. All rights reserved. Molecular phylogeny. 1. Introduction the order Entactinarida has an inner spicular system homologenous with that of the order Nassellarida.
    [Show full text]
  • Download This Publication (PDF File)
    PUBLIC LIBRARY of SCIENCE | plosgenetics.org | ISSN 1553-7390 | Volume 2 | Issue 12 | DECEMBER 2006 GENETICS PUBLIC LIBRARY of SCIENCE www.plosgenetics.org Volume 2 | Issue 12 | DECEMBER 2006 Interview Review Knight in Common Armor: 1949 Unraveling the Genetics 1956 An Interview with Sir John Sulston e225 of Human Obesity e188 Jane Gitschier David M. Mutch, Karine Clément Research Articles Natural Variants of AtHKT1 1964 The Complete Genome 2039 Enhance Na+ Accumulation e210 Sequence and Comparative e206 in Two Wild Populations of Genome Analysis of the High Arabidopsis Pathogenicity Yersinia Ana Rus, Ivan Baxter, enterocolitica Strain 8081 Balasubramaniam Muthukumar, Nicholas R. Thomson, Sarah Jeff Gustin, Brett Lahner, Elena Howard, Brendan W. Wren, Yakubova, David E. Salt Matthew T. G. Holden, Lisa Crossman, Gregory L. Challis, About the Cover Drosophila SPF45: A Bifunctional 1974 Carol Churcher, Karen The jigsaw image of representatives Protein with Roles in Both e178 Mungall, Karen Brooks, Tracey of various lines of eukaryote evolution Splicing and DNA Repair Chillingworth, Theresa Feltwell, refl ects the current lack of consensus as Ahmad Sami Chaouki, Helen K. Zahra Abdellah, Heidi Hauser, to how the major branches of eukaryotes Salz Kay Jagels, Mark Maddison, fi t together. The illustrations from upper Sharon Moule, Mandy Sanders, left to bottom right are as follows: a single Mammalian Small Nucleolar 1984 Sally Whitehead, Michael A. scale from the surface of Umbellosphaera; RNAs Are Mobile Genetic e205 Quail, Gordon Dougan, Julian Amoeba, the large amoeboid organism Elements Parkhill, Michael B. Prentice used as an introduction to protists for Michel J. Weber many school children; Euglena, the iconic Low Levels of Genetic 2052 fl agellate that is often used to challenge Soft Sweeps III: The Signature 1998 Divergence across e215 ideas of plants (Euglena has chloroplasts) of Positive Selection from e186 Geographically and and animals (Euglena moves); Stentor, Recurrent Mutation Linguistically Diverse one of the larger ciliates; Cacatua, the Pleuni S.
    [Show full text]
  • Broadly Sampled Multigene Analyses Yield a Well-Resolved Eukaryotic Tree of Life
    Smith ScholarWorks Biological Sciences: Faculty Publications Biological Sciences 10-1-2010 Broadly Sampled Multigene Analyses Yield a Well-Resolved Eukaryotic Tree of Life Laura Wegener Parfrey University of Massachusetts Amherst Jessica Grant Smith College Yonas I. Tekle Smith College Erica Lasek-Nesselquist Marine Biological Laboratory Hilary G. Morrison Marine Biological Laboratory See next page for additional authors Follow this and additional works at: https://scholarworks.smith.edu/bio_facpubs Part of the Biology Commons Recommended Citation Parfrey, Laura Wegener; Grant, Jessica; Tekle, Yonas I.; Lasek-Nesselquist, Erica; Morrison, Hilary G.; Sogin, Mitchell L.; Patterson, David J.; and Katz, Laura A., "Broadly Sampled Multigene Analyses Yield a Well-Resolved Eukaryotic Tree of Life" (2010). Biological Sciences: Faculty Publications, Smith College, Northampton, MA. https://scholarworks.smith.edu/bio_facpubs/126 This Article has been accepted for inclusion in Biological Sciences: Faculty Publications by an authorized administrator of Smith ScholarWorks. For more information, please contact [email protected] Authors Laura Wegener Parfrey, Jessica Grant, Yonas I. Tekle, Erica Lasek-Nesselquist, Hilary G. Morrison, Mitchell L. Sogin, David J. Patterson, and Laura A. Katz This article is available at Smith ScholarWorks: https://scholarworks.smith.edu/bio_facpubs/126 Syst. Biol. 59(5):518–533, 2010 c The Author(s) 2010. Published by Oxford University Press, on behalf of the Society of Systematic Biologists. All rights reserved. For Permissions, please email: [email protected] DOI:10.1093/sysbio/syq037 Advance Access publication on July 23, 2010 Broadly Sampled Multigene Analyses Yield a Well-Resolved Eukaryotic Tree of Life LAURA WEGENER PARFREY1,JESSICA GRANT2,YONAS I. TEKLE2,6,ERICA LASEK-NESSELQUIST3,4, 3 3 5 1,2, HILARY G.
    [Show full text]
  • Identification of a Novel Fused Gene Family Implicates Convergent
    Chen et al. BMC Genomics (2018) 19:306 https://doi.org/10.1186/s12864-018-4685-y RESEARCH ARTICLE Open Access Identification of a novel fused gene family implicates convergent evolution in eukaryotic calcium signaling Fei Chen1,2,3, Liangsheng Zhang1, Zhenguo Lin4 and Zong-Ming Max Cheng2,3* Abstract Background: Both calcium signals and protein phosphorylation responses are universal signals in eukaryotic cell signaling. Currently three pathways have been characterized in different eukaryotes converting the Ca2+ signals to the protein phosphorylation responses. All these pathways have based mostly on studies in plants and animals. Results: Based on the exploration of genomes and transcriptomes from all the six eukaryotic supergroups, we report here in Metakinetoplastina protists a novel gene family. This family, with a proposed name SCAMK,comprisesSnRK3 fused calmodulin-like III kinase genes and was likely evolved through the insertion of a calmodulin-like3 gene into an SnRK3 gene by unequal crossover of homologous chromosomes in meiosis cell. Its origin dated back to the time intersection at least 450 million-year-ago when Excavata parasites, Vertebrata hosts, and Insecta vectors evolved. We also analyzed SCAMK’s unique expression pattern and structure, and proposed it as one of the leading calcium signal conversion pathways in Excavata parasite. These characters made SCAMK gene as a potential drug target for treating human African trypanosomiasis. Conclusions: This report identified a novel gene fusion and dated its precise fusion time
    [Show full text]
  • Sex Is a Ubiquitous, Ancient, and Inherent Attribute of Eukaryotic Life
    PAPER Sex is a ubiquitous, ancient, and inherent attribute of COLLOQUIUM eukaryotic life Dave Speijera,1, Julius Lukešb,c, and Marek Eliášd,1 aDepartment of Medical Biochemistry, Academic Medical Center, University of Amsterdam, 1105 AZ, Amsterdam, The Netherlands; bInstitute of Parasitology, Biology Centre, Czech Academy of Sciences, and Faculty of Sciences, University of South Bohemia, 370 05 Ceské Budejovice, Czech Republic; cCanadian Institute for Advanced Research, Toronto, ON, Canada M5G 1Z8; and dDepartment of Biology and Ecology, University of Ostrava, 710 00 Ostrava, Czech Republic Edited by John C. Avise, University of California, Irvine, CA, and approved April 8, 2015 (received for review February 14, 2015) Sexual reproduction and clonality in eukaryotes are mostly Sex in Eukaryotic Microorganisms: More Voyeurs Needed seen as exclusive, the latter being rather exceptional. This view Whereas absence of sex is considered as something scandalous for might be biased by focusing almost exclusively on metazoans. a zoologist, scientists studying protists, which represent the ma- We analyze and discuss reproduction in the context of extant jority of extant eukaryotic diversity (2), are much more ready to eukaryotic diversity, paying special attention to protists. We accept that a particular eukaryotic group has not shown any evi- present results of phylogenetically extended searches for ho- dence of sexual processes. Although sex is very well documented mologs of two proteins functioning in cell and nuclear fusion, in many protist groups, and members of some taxa, such as ciliates respectively (HAP2 and GEX1), providing indirect evidence for (Alveolata), diatoms (Stramenopiles), or green algae (Chlor- these processes in several eukaryotic lineages where sex has oplastida), even serve as models to study various aspects of sex- – not been observed yet.
    [Show full text]
  • Are Blastocystis Species Clinically Relevant to Humans?
    Are Blastocystis species clinically relevant to humans? Robyn Anne Nagel MB, BS, FRACP A thesis submitted for the degree of Doctor of Philosophy at the University of Queensland in 2015 School of Veterinary Science Title page Culture of human faecal specimen Blastocystis organisms, vacuolated and granular forms, Photographed RAN: x40 magnification, polarised light ii Abstract Blastocystis spp. are the most common enteric parasites found in human stool and yet, the life cycle of the organism is unknown and the clinical relevance uncertain. Robust cysts transmit infection, and many animals carry the parasite. Infection in humans has been linked to Irritable bowel syndrome (IBS). Although Blastocystis carriage is much higher in IBS patients, studies have not been able to confirm Blastocystis spp. are the direct cause of symptoms. Moreover, eradication is often unsuccessful. A number of approaches were utilised in order to investigate the clinical relevance of Blastocystis spp. in human IBS patients. Deconvolutional microscopy with time-lapse imaging and fluorescent spectroscopy of xenic cultures of Blastocystis spp. from IBS patients and healthy individuals was performed. Green autofluorescence (GAF), most prominently in the 557/576 emission spectra, was observed in the vacuolated, granular, amoebic and cystic Blastocystis forms. This first report of GAF in Blastocystis showed that a Blastocystis-specific fluorescein-conjugated antibody could be partially distinguished from GAF. Surface pores of 1m in diameter were observed cyclically opening and closing over 24 hours and may have nutritional or motility functions. Vacuolated forms, extruded a viscous material slowly over 12 hours, a process likely involving osmoregulation. Tear- shaped granules were observed exiting from the surface of an amoebic form but their identity and function could not be elucidated.
    [Show full text]
  • (Alveolata) As Inferred from Hsp90 and Actin Phylogenies1
    J. Phycol. 40, 341–350 (2004) r 2004 Phycological Society of America DOI: 10.1111/j.1529-8817.2004.03129.x EARLY EVOLUTIONARY HISTORY OF DINOFLAGELLATES AND APICOMPLEXANS (ALVEOLATA) AS INFERRED FROM HSP90 AND ACTIN PHYLOGENIES1 Brian S. Leander2 and Patrick J. Keeling Canadian Institute for Advanced Research, Program in Evolutionary Biology, Departments of Botany and Zoology, University of British Columbia, Vancouver, British Columbia, Canada Three extremely diverse groups of unicellular The Alveolata is one of the most biologically diverse eukaryotes comprise the Alveolata: ciliates, dino- supergroups of eukaryotic microorganisms, consisting flagellates, and apicomplexans. The vast phenotypic of ciliates, dinoflagellates, apicomplexans, and several distances between the three groups along with the minor lineages. Although molecular phylogenies un- enigmatic distribution of plastids and the economic equivocally support the monophyly of alveolates, and medical importance of several representative members of the group share only a few derived species (e.g. Plasmodium, Toxoplasma, Perkinsus, and morphological features, such as distinctive patterns of Pfiesteria) have stimulated a great deal of specula- cortical vesicles (syn. alveoli or amphiesmal vesicles) tion on the early evolutionary history of alveolates. subtending the plasma membrane and presumptive A robust phylogenetic framework for alveolate pinocytotic structures, called ‘‘micropores’’ (Cavalier- diversity will provide the context necessary for Smith 1993, Siddall et al. 1997, Patterson
    [Show full text]
  • Multigene Eukaryote Phylogeny Reveals the Likely Protozoan Ancestors of Opis- Thokonts (Animals, Fungi, Choanozoans) and Amoebozoa
    Accepted Manuscript Multigene eukaryote phylogeny reveals the likely protozoan ancestors of opis- thokonts (animals, fungi, choanozoans) and Amoebozoa Thomas Cavalier-Smith, Ema E. Chao, Elizabeth A. Snell, Cédric Berney, Anna Maria Fiore-Donno, Rhodri Lewis PII: S1055-7903(14)00279-6 DOI: http://dx.doi.org/10.1016/j.ympev.2014.08.012 Reference: YMPEV 4996 To appear in: Molecular Phylogenetics and Evolution Received Date: 24 January 2014 Revised Date: 2 August 2014 Accepted Date: 11 August 2014 Please cite this article as: Cavalier-Smith, T., Chao, E.E., Snell, E.A., Berney, C., Fiore-Donno, A.M., Lewis, R., Multigene eukaryote phylogeny reveals the likely protozoan ancestors of opisthokonts (animals, fungi, choanozoans) and Amoebozoa, Molecular Phylogenetics and Evolution (2014), doi: http://dx.doi.org/10.1016/ j.ympev.2014.08.012 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. 1 1 Multigene eukaryote phylogeny reveals the likely protozoan ancestors of opisthokonts 2 (animals, fungi, choanozoans) and Amoebozoa 3 4 Thomas Cavalier-Smith1, Ema E. Chao1, Elizabeth A. Snell1, Cédric Berney1,2, Anna Maria 5 Fiore-Donno1,3, and Rhodri Lewis1 6 7 1Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK.
    [Show full text]
  • Lateral Transfer of Eukaryotic Ribosomal RNA Genes: an Emerging Concern for Molecular Ecology of Microbial Eukaryotes
    The ISME Journal (2014) 8, 1544–1547 & 2014 International Society for Microbial Ecology All rights reserved 1751-7362/14 OPEN www.nature.com/ismej SHORT COMMUNICATION Lateral transfer of eukaryotic ribosomal RNA genes: an emerging concern for molecular ecology of microbial eukaryotes Akinori Yabuki, Takashi Toyofuku and Kiyotaka Takishita Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima, Yokosuka, Kanagawa, Japan Ribosomal RNA (rRNA) genes are widely utilized in depicting organismal diversity and distribution in a wide range of environments. Although a few cases of lateral transfer of rRNA genes between closely related prokaryotes have been reported, it remains to be reported from eukaryotes. Here, we report the first case of lateral transfer of eukaryotic rRNA genes. Two distinct sequences of the 18S rRNA gene were detected from a clonal culture of the stramenopile, Ciliophrys infusionum. One was clearly derived from Ciliophrys, but the other gene originated from a perkinsid alveolate. Genome- walking analyses revealed that this alveolate-type rRNA gene is immediately adjacent to two protein- coding genes (ubc12 and usp39), and the origin of both genes was shown to be a stramenopile (that is, Ciliophrys) in our phylogenetic analyses. These findings indicate that the alveolate-type rRNA gene is encoded on the Ciliophrys genome and that eukaryotic rRNA genes can be transferred laterally. The ISME Journal (2014) 8, 1544–1547; doi:10.1038/ismej.2013.252; published online 23 January 2014 Subject Category: Microbial population and community ecology Keywords: 18S rRNA gene; environmental DNA; lateral gene transfer Genes that are involved in transcription, translation Recently, we established a clonal culture of and related processes, and interacted with many Ciliophrys infusionum (deposited as NIES-3355) partner molecules are believed to be less transferable from the sediment of the lagoon ‘Kai-ike’ (Satsuma- between different organisms (Rivera et al., 1998; Jain sendai, Kagoshima, Japan).
    [Show full text]
  • A Revised Classification of Naked Lobose Amoebae (Amoebozoa
    Protist, Vol. 162, 545–570, October 2011 http://www.elsevier.de/protis Published online date 28 July 2011 PROTIST NEWS A Revised Classification of Naked Lobose Amoebae (Amoebozoa: Lobosa) Introduction together constitute the amoebozoan subphy- lum Lobosa, which never have cilia or flagella, Molecular evidence and an associated reevaluation whereas Variosea (as here revised) together with of morphology have recently considerably revised Mycetozoa and Archamoebea are now grouped our views on relationships among the higher-level as the subphylum Conosa, whose constituent groups of amoebae. First of all, establishing the lineages either have cilia or flagella or have lost phylum Amoebozoa grouped all lobose amoe- them secondarily (Cavalier-Smith 1998, 2009). boid protists, whether naked or testate, aerobic Figure 1 is a schematic tree showing amoebozoan or anaerobic, with the Mycetozoa and Archamoe- relationships deduced from both morphology and bea (Cavalier-Smith 1998), and separated them DNA sequences. from both the heterolobosean amoebae (Page and The first attempt to construct a congruent molec- Blanton 1985), now belonging in the phylum Per- ular and morphological system of Amoebozoa by colozoa - Cavalier-Smith and Nikolaev (2008), and Cavalier-Smith et al. (2004) was limited by the the filose amoebae that belong in other phyla lack of molecular data for many amoeboid taxa, (notably Cercozoa: Bass et al. 2009a; Howe et al. which were therefore classified solely on morpho- 2011). logical evidence. Smirnov et al. (2005) suggested The phylum Amoebozoa consists of naked and another system for naked lobose amoebae only; testate lobose amoebae (e.g. Amoeba, Vannella, this left taxa with no molecular data incertae sedis, Hartmannella, Acanthamoeba, Arcella, Difflugia), which limited its utility.
    [Show full text]