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Liu L, Wang H, Luo Z, Chen J. Biogeographic patterns of micro-eukaryotic generalists and specialists and their effects on regional α-diversity at inter-oceanic scale. MARINE ENVIRONMENTAL RESEARCH 2024; 193:106261. [PMID: 37981448 DOI: 10.1016/j.marenvres.2023.106261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 10/31/2023] [Accepted: 11/09/2023] [Indexed: 11/21/2023]
Abstract
Inter-oceanic scale studies allow us to understand the global spread of micro-organisms in marine ecosystems. In this study, micro-eukaryotic communities in marine surface sediment were collected from tropical to Arctic sites. We found that micro-eukaryotic generalists had much higher intraspecific variation than specialists which allow them to distribute more widely through higher spatiotemporal asynchrony and complementary niche preferences among conspecific taxa. Moreover, comparing to the host-associated protozoa and small metazoa, the algae and free-living protozoa with higher intraspecific variation allow them to have wider distribution ranges. Species abundance also played an important role in driving the distribution ranges of generalists and specialists. The generalists had important effects on regional α-diversity even at an inter-oceanic scale which led to the micro-eukaryotic species richness in polar sites to be mainly influenced by the regional generalists but not the local specialists. In particular, more than 97% of algal species in polar sites were shared with the tropical and subtropical sites (including toxic dinoflagellate). Overall, our study suggests that the effects of global change and human activities on the vulnerable high latitude habitats may lead to biotic homogenization for the whole microbial community (not only the dispersal of some harmful algae) through the potential long-distance spread of generalists.
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Affiliation(s)
- Lemian Liu
- College of Biological Science and Engineering, Fuzhou University, Fuzhou 350108, China; Marine Engineering Research and Development Center of Jinjiang Science and Education Park, Fuzhou University, Fuzhou 350108, China.
| | - Hongwei Wang
- College of Biological Science and Engineering, Fuzhou University, Fuzhou 350108, China; Marine Engineering Research and Development Center of Jinjiang Science and Education Park, Fuzhou University, Fuzhou 350108, China
| | - Zhaohe Luo
- Third Institute of Oceanography, Ministry of Natural Resources, Xiamen 361005, China; Key Laboratory of Marine Ecological Conservation and Restoration, Ministry of Natural Resources, Xiamen 361005, China.
| | - Jianfeng Chen
- College of Biological Science and Engineering, Fuzhou University, Fuzhou 350108, China; Marine Engineering Research and Development Center of Jinjiang Science and Education Park, Fuzhou University, Fuzhou 350108, China
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2
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Levy Karin E, Mirdita M, Söding J. MetaEuk-sensitive, high-throughput gene discovery, and annotation for large-scale eukaryotic metagenomics. MICROBIOME 2020; 8:48. [PMID: 32245390 PMCID: PMC7126354 DOI: 10.1186/s40168-020-00808-x] [Citation(s) in RCA: 98] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 02/14/2020] [Indexed: 05/10/2023]
Abstract
BACKGROUND Metagenomics is revolutionizing the study of microorganisms and their involvement in biological, biomedical, and geochemical processes, allowing us to investigate by direct sequencing a tremendous diversity of organisms without the need for prior cultivation. Unicellular eukaryotes play essential roles in most microbial communities as chief predators, decomposers, phototrophs, bacterial hosts, symbionts, and parasites to plants and animals. Investigating their roles is therefore of great interest to ecology, biotechnology, human health, and evolution. However, the generally lower sequencing coverage, their more complex gene and genome architectures, and a lack of eukaryote-specific experimental and computational procedures have kept them on the sidelines of metagenomics. RESULTS MetaEuk is a toolkit for high-throughput, reference-based discovery, and annotation of protein-coding genes in eukaryotic metagenomic contigs. It performs fast searches with 6-frame-translated fragments covering all possible exons and optimally combines matches into multi-exon proteins. We used a benchmark of seven diverse, annotated genomes to show that MetaEuk is highly sensitive even under conditions of low sequence similarity to the reference database. To demonstrate MetaEuk's power to discover novel eukaryotic proteins in large-scale metagenomic data, we assembled contigs from 912 samples of the Tara Oceans project. MetaEuk predicted >12,000,000 protein-coding genes in 8 days on ten 16-core servers. Most of the discovered proteins are highly diverged from known proteins and originate from very sparsely sampled eukaryotic supergroups. CONCLUSION The open-source (GPLv3) MetaEuk software (https://github.com/soedinglab/metaeuk) enables large-scale eukaryotic metagenomics through reference-based, sensitive taxonomic and functional annotation. Video abstract.
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Affiliation(s)
- Eli Levy Karin
- Quantitative and Computational Biology, Max-Planck Institute for Biophysical Chemistry, 37077, Göttingen, Germany.
| | - Milot Mirdita
- Quantitative and Computational Biology, Max-Planck Institute for Biophysical Chemistry, 37077, Göttingen, Germany
| | - Johannes Söding
- Quantitative and Computational Biology, Max-Planck Institute for Biophysical Chemistry, 37077, Göttingen, Germany.
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3
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Christodoulou M, O'Hara TD, Hugall AF, Arbizu PM. Dark Ophiuroid Biodiversity in a Prospective Abyssal Mine Field. Curr Biol 2019; 29:3909-3912.e3. [PMID: 31630951 DOI: 10.1016/j.cub.2019.09.012] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 07/04/2019] [Accepted: 09/05/2019] [Indexed: 01/30/2023]
Abstract
The seafloor contains valuable mineral resources, including polymetallic (or manganese) nodules that form on offshore abyssal plains. The largest and most commercially attractive deposits are located in the Clarion Clipperton Fracture Zone (CCZ), in the eastern Pacific Ocean (EP) between Hawaii and Mexico, where testing of a mineral collection system is set to start soon [1]. The requirement to establish pre-mining environmental management plans has prompted numerous recent biodiversity and DNA barcoding surveys across these remote regions. Here we map DNA sequences from sampled ophiuroids (brittle stars, including post-larvae) of the CCZ and Peru Basin onto a substantial tree of life to show unprecedented levels of abyssal ophiuroid phylogenetic diversity including at least three ancient (>70 Ma), previously unknown clades. While substantial dark (unobserved) biodiversity has been reported from various microbial meta-barcoding projects [2, 3], our data show that we have considerably under-estimated the biodiversity of even the most conspicuous mega-faunal invertebrates [4] of the EP abyssal plain.
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Affiliation(s)
- Magdalini Christodoulou
- German Centre for Marine Biodiversity Research, Senckenberg am Meer, Südstrand 44, 26382 Wilhelmshaven, Germany
| | - Timothy D O'Hara
- Museums Victoria, Sciences Department, 11 Nicholson Street, Carlton 3054, VIC, Australia.
| | - Andrew F Hugall
- Museums Victoria, Sciences Department, 11 Nicholson Street, Carlton 3054, VIC, Australia
| | - Pedro Martinez Arbizu
- German Centre for Marine Biodiversity Research, Senckenberg am Meer, Südstrand 44, 26382 Wilhelmshaven, Germany
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4
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Brown MW, Heiss AA, Kamikawa R, Inagaki Y, Yabuki A, Tice AK, Shiratori T, Ishida KI, Hashimoto T, Simpson AGB, Roger AJ. Phylogenomics Places Orphan Protistan Lineages in a Novel Eukaryotic Super-Group. Genome Biol Evol 2018; 10:427-433. [PMID: 29360967 PMCID: PMC5793813 DOI: 10.1093/gbe/evy014] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/18/2018] [Indexed: 01/13/2023] Open
Abstract
Recent phylogenetic analyses position certain “orphan” protist lineages deep in the tree of eukaryotic life, but their exact placements are poorly resolved. We conducted phylogenomic analyses that incorporate deeply sequenced transcriptomes from representatives of collodictyonids (diphylleids), rigifilids, Mantamonas, and ancyromonads (planomonads). Analyses of 351 genes, using site-heterogeneous mixture models, strongly support a novel super-group-level clade that includes collodictyonids, rigifilids, and Mantamonas, which we name “CRuMs”. Further, they robustly place CRuMs as the closest branch to Amorphea (including animals and fungi). Ancyromonads are strongly inferred to be more distantly related to Amorphea than are CRuMs. They emerge either as sister to malawimonads, or as a separate deeper branch. CRuMs and ancyromonads represent two distinct major groups that branch deeply on the lineage that includes animals, near the most commonly inferred root of the eukaryote tree. This makes both groups crucial in examinations of the deepest-level history of extant eukaryotes.
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Affiliation(s)
- Matthew W Brown
- Department of Biological Sciences, Mississippi State University, USA.,Institute for Genomics, Biocomputing & Biotechnology, Mississippi State University, USA
| | - Aaron A Heiss
- Department of Biology, and Centre for Comparative Genomics and Evolutionary Bioinformatics, Dalhousie University, Halifax, Nova Scotia, Canada.,Department of Invertebrate Zoology and Sackler Institute for Comparative Genomics, American Museum of Natural History, New York, New York, USA
| | - Ryoma Kamikawa
- Graduate School of Human and Environmental Studies, Graduate School of Global Environmental Studies, Kyoto University, Japan
| | - Yuji Inagaki
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Ibaraki, Japan.,Center for Computational Sciences, University of Tsukuba, Ibaraki, Japan
| | - Akinori Yabuki
- Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokosuka, Kanagawa, Japan
| | - Alexander K Tice
- Department of Biological Sciences, Mississippi State University, USA.,Institute for Genomics, Biocomputing & Biotechnology, Mississippi State University, USA
| | - Takashi Shiratori
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Ibaraki, Japan
| | - Ken-Ichiro Ishida
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Ibaraki, Japan
| | - Tetsuo Hashimoto
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Ibaraki, Japan.,Center for Computational Sciences, University of Tsukuba, Ibaraki, Japan
| | - Alastair G B Simpson
- Department of Biology, and Centre for Comparative Genomics and Evolutionary Bioinformatics, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Andrew J Roger
- Department of Biochemistry and Molecular Biology, and Centre for Comparative Genomics and Evolutionary Bioinformatics, Dalhousie University, Halifax, Nova Scotia, Canada
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5
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Geisen S, Mitchell EAD, Adl S, Bonkowski M, Dunthorn M, Ekelund F, Fernández LD, Jousset A, Krashevska V, Singer D, Spiegel FW, Walochnik J, Lara E. Soil protists: a fertile frontier in soil biology research. FEMS Microbiol Rev 2018; 42:293-323. [DOI: 10.1093/femsre/fuy006] [Citation(s) in RCA: 212] [Impact Index Per Article: 35.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Accepted: 02/12/2018] [Indexed: 12/27/2022] Open
Affiliation(s)
- Stefan Geisen
- Department of Terrestrial Ecology, Netherlands Institute of Ecology, 6708 PB Wageningen, The Netherlands
- Laboratory of Nematology, Wageningen University, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands
| | - Edward A D Mitchell
- Laboratory of Soil Biodiversity, University of Neuchâtel, Rue Emile-Argand 11, Neuchâtel 2000, Switzerland
- Jardin Botanique de Neuchâtel, Chemin du Perthuis-du-Sault 58, Neuchâtel 2000, Switzerland
| | - Sina Adl
- Department of Soil Sciences, College of Agriculture and Bioresources, University of Saskatchewan, 51 Campus Drive, Saskatoon, Canada
| | - Michael Bonkowski
- Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, Institute of Zoology, Terrestrial Ecology, Zülpicher Straße 47b, 50674 Köln, Germany
| | - Micah Dunthorn
- Department of Ecology, University of Kaiserslautern, Erwin-Schrödinger Straße, 67663 Kaiserslautern, Germany
| | - Flemming Ekelund
- Department of Biology, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen, Denmark
| | - Leonardo D Fernández
- Centro de Investigación en Recursos Naturales y Sustentabilidad (CIRENYS), Universidad Bernardo O’Higgins, Avenida Viel 1497, Santiago, Chile
| | - Alexandre Jousset
- Department of Ecology and Biodiversity, Utrecht University, 3584 CH Utrecht, The Netherlands
| | - Valentyna Krashevska
- University of Göttingen, J.F. Blumenbach Institute of Zoology and Anthropology, Untere Karspüle 2, 37073 Göttingen, Germany
| | - David Singer
- Laboratory of Soil Biodiversity, University of Neuchâtel, Rue Emile-Argand 11, Neuchâtel 2000, Switzerland
| | - Frederick W Spiegel
- Department of Biological Sciences, University of Arkansas, Fayetteville, AR, 72701, United States of America
| | - Julia Walochnik
- Molecular Parasitology, Institute of Tropical Medicine, Medical University, 1090 Vienna, Austria
| | - Enrique Lara
- Laboratory of Soil Biodiversity, University of Neuchâtel, Rue Emile-Argand 11, Neuchâtel 2000, Switzerland
- Real Jardín Botánico, CSIC, Plaza de Murillo 2, 28014 Madrid, Spain
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6
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Phylogeny mandalas for illustrating the Tree of Life. Mol Phylogenet Evol 2017; 117:168-178. [DOI: 10.1016/j.ympev.2016.11.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 10/12/2016] [Accepted: 11/01/2016] [Indexed: 01/01/2023]
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7
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Leray M, Knowlton N. Censusing marine eukaryotic diversity in the twenty-first century. Philos Trans R Soc Lond B Biol Sci 2017; 371:rstb.2015.0331. [PMID: 27481783 PMCID: PMC4971183 DOI: 10.1098/rstb.2015.0331] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/26/2016] [Indexed: 11/12/2022] Open
Abstract
The ocean constitutes one of the vastest and richest biomes on our planet. Most recent estimations, all based on indirect approaches, suggest that there are millions of marine eukaryotic species. Moreover, a large majority of these are small (less than 1 mm), cryptic and still unknown to science. However, this knowledge gap, caused by the lack of diagnostic morphological features in small organisms and the limited sampling of the global ocean, is currently being filled, thanks to new DNA-based approaches. The molecular technique of PCR amplification of homologous gene regions combined with high-throughput sequencing, routinely used to census unculturable prokaryotes, is now also being used to characterize whole communities of marine eukaryotes. Here, we review how this methodological advancement has helped to better quantify the magnitude and patterns of marine eukaryotic diversity, with an emphasis on taxonomic groups previously largely overlooked. We then discuss obstacles remaining to achieve a global understanding of marine eukaryotic diversity. In particular, we argue that 18S variable regions do not provide sufficient taxonomic resolution to census marine life, and suggest combining broad eukaryotic surveys targeting the 18S rRNA region with more taxon-focused analyses of hypervariable regions to improve our understanding of the diversity of species, the functional units of marine ecosystems. This article is part of the themed issue ‘From DNA barcodes to biomes’.
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Affiliation(s)
- Matthieu Leray
- National Museum of Natural History, Smithsonian Institution, Washington, DC 20013, USA
| | - Nancy Knowlton
- National Museum of Natural History, Smithsonian Institution, Washington, DC 20013, USA
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8
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Borg Dahl M, Brejnrod AD, Unterseher M, Hoppe T, Feng Y, Novozhilov Y, Sørensen SJ, Schnittler M. Genetic barcoding of dark-spored myxomycetes (Amoebozoa)-Identification, evaluation and application of a sequence similarity threshold for species differentiation in NGS studies. Mol Ecol Resour 2017; 18:306-318. [PMID: 29024429 DOI: 10.1111/1755-0998.12725] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Revised: 09/26/2017] [Accepted: 10/01/2017] [Indexed: 12/18/2022]
Abstract
Unicellular, eukaryotic organisms (protists) play a key role in soil food webs as major predators of microorganisms. However, due to the polyphyletic nature of protists, no single universal barcode can be established for this group, and the structure of many protistean communities remains unresolved. Plasmodial slime moulds (Myxogastria or Myxomycetes) stand out among protists by their formation of fruit bodies, which allow for a morphological species concept. By Sanger sequencing of a large collection of morphospecies, this study presents the largest database to date of dark-spored myxomycetes and evaluate a partial 18S SSU gene marker for species annotation. We identify and discuss the use of an intraspecific sequence similarity threshold of 99.1% for species differentiation (OTU picking) in environmental PCR studies (ePCR) and estimate a hidden diversity of putative species, exceeding those of described morphospecies by 99%. When applying the identified threshold to an ePCR data set (including sequences from both NGS and cloning), we find 64 OTUs of which 21.9% had a direct match (>99.1% similarity) to the database and the remaining had on average 90.2 ± 0.8% similarity to their best match, thus thought to represent undiscovered diversity of dark-spored myxomycetes.
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Affiliation(s)
- Mathilde Borg Dahl
- Institute of Botany and Landscape Ecology, Ernst Moritz Arndt University of Greifswald, Greifswald, Germany
| | - Asker D Brejnrod
- Section of Microbiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | | | - Thomas Hoppe
- Institute of Botany and Landscape Ecology, Ernst Moritz Arndt University of Greifswald, Greifswald, Germany
| | - Yun Feng
- Institute of Botany and Landscape Ecology, Ernst Moritz Arndt University of Greifswald, Greifswald, Germany
| | - Yuri Novozhilov
- V.L. Komarov Botanical Institute of the Russian Academy of Sciences, St. Petersburg, Russia
| | - Søren J Sørensen
- Section of Microbiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Martin Schnittler
- Institute of Botany and Landscape Ecology, Ernst Moritz Arndt University of Greifswald, Greifswald, Germany
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9
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Dagamac NHA, Rojas C, Novozhilov YK, Moreno GH, Schlueter R, Schnittler M. Speciation in progress? A phylogeographic study among populations of Hemitrichia serpula (Myxomycetes). PLoS One 2017; 12:e0174825. [PMID: 28414791 PMCID: PMC5393559 DOI: 10.1371/journal.pone.0174825] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2017] [Accepted: 03/15/2017] [Indexed: 11/19/2022] Open
Abstract
Myxomycetes (plasmodial slime molds, Amoebozoa) are often perceived as widely distributed, confounding to the “everything is everywhere” hypothesis. To test if gene flow within these spore-dispersed protists is restricted by geographical barriers, we chose the widespread but morphologically unmistakable species Hemitrichia serpula for a phylogeographic study. Partial sequences from nuclear ribosomal RNA genes (SSU) revealed 40 ribotypes among 135 specimens, belonging to three major clades. Each clade is dominated by specimens from a certain region and by one of two morphological varieties which can be differentiated by SEM micrographs. Partial sequences of the protein elongation factor 1 alpha (EF1A) showed each clade to possess a unique combination of SSU and EF1A genotypes. This pattern is best explained assuming the existence of several putative biospecies dominating in a particular geographical region. However, occasional mismatches between molecular data and morphological characters, but as well heterogeneous SSU and heterozygous EF1A sequences, point to ongoing speciation. Environmental niche models suggest that the putative biospecies are rather restricted by geographical barriers than by macroecological conditions. Like other protists, myxomycetes seem to follow the moderate endemicity hypothesis and are in active speciation, which is most likely shaped by limited gene flow and reproductive isolation.
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Affiliation(s)
- Nikki Heherson A. Dagamac
- Institute of Botany and Landscape Ecology, Ernst Moritz Arndt University Greifswald, Soldmannstr. 15, Greifswald, Germany
- * E-mail: (NHAD); (MS)
| | - Carlos Rojas
- Engineering Research Institute and Department of Agricultural Engineering, University of Costa Rica, San Pedro de Montes de Oca, Costa Rica
| | - Yuri K. Novozhilov
- Komarov Botanical Institute of the Russian Academy of Sciences, Laboratory of Systematics and Geography of Fungi, St. Petersburg, Russia
| | - Gabriel H. Moreno
- Departamento de Biología Vegetal, Universidad de Alcalá, Alcalá de Henares, Madrid, Spain
| | - Rabea Schlueter
- Laboratory of Electron Microscopy, Institute of Microbiology, Ernst Moritz Arndt University Greifswald, Greifswald, Germany
| | - Martin Schnittler
- Institute of Botany and Landscape Ecology, Ernst Moritz Arndt University Greifswald, Soldmannstr. 15, Greifswald, Germany
- * E-mail: (NHAD); (MS)
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10
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Olivera IE, Fins KC, Rodriguez SA, Abiff SK, Tartar JL, Tartar A. Glycoside hydrolases family 20 (GH20) represent putative virulence factors that are shared by animal pathogenic oomycetes, but are absent in phytopathogens. BMC Microbiol 2016; 16:232. [PMID: 27716041 PMCID: PMC5053185 DOI: 10.1186/s12866-016-0856-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Accepted: 09/28/2016] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND Although interest in animal pathogenic oomycetes is increasing, the molecular basis mediating oomycete-animal relationships remains virtually unknown. Crinkler (CRN) genes, which have been traditionally associated with the cytotoxic activity displayed by plant pathogenic oomycetes, were recently detected in transcriptome sequences from the entomopathogenic oomycete Lagenidium giganteum, suggesting that these genes may represent virulence factors conserved in both animal and plant pathogenic oomycetes. In order to further characterize the L. giganteum pathogenome, an on-going genomic survey was mined to reveal novel putative virulence factors, including canonical oomycete effectors Crinkler 13 (CRN13) orthologs. These novel sequences provided a basis to initiate gene expression analyses and determine if the proposed L. giganteum virulence factors are differentially expressed in the presence of mosquito larvae (Aedes aegypti). RESULTS Sequence analyses revealed that L. giganteum express CRN13 transcripts. The predicted proteins, like other L. giganteum CRNs, contained a conserved LYLA motif at the N terminal, but did not display signal peptides. In contrast, other potential virulence factors, such as Glycoside Hydrolases family 20 (hexosaminidase) and 37 (trehalase) proteins (GH20 and GH37), contained identifiable signal peptides. Genome mining demonstrated that GH20 genes are absent from phytopathogenic oomycete genomes, and that the L. giganteum GH20 sequence is the only reported peronosporalean GH20 gene. All other oomycete GH20 homologs were retrieved from animal pathogenic, saprolegnialean genomes. Furthermore, phylogenetic analyses demonstrated that saprolegnialean and peronosporalean GH20 protein sequences clustered in unrelated clades. The saprolegnialean GH20 sequences appeared as a strongly supported, monophyletic group nested within an arthropod-specific clade, suggesting that this gene was acquired via a lateral gene transfer event from an insect or crustacean genome. In contrast, the L. giganteum GH20 protein sequence appeared as a sister taxon to a plant-specific clade that included exochitinases with demonstrated insecticidal activities. Finally, gene expression analyses demonstrated that the L. giganteum GH20 gene expression level is significantly modulated in the presence of mosquito larvae. In agreement with the protein secretion predictions, CRN transcripts did not show any differential expression. CONCLUSIONS These results identified GH20 enzymes, and not CRNs, as potential pathogenicity factors shared by all animal pathogenic oomycetes.
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Affiliation(s)
- Isabel E Olivera
- Department of Biological Sciences, Nova Southeastern University, Fort Lauderdale, FL, USA
| | - Katrina C Fins
- Department of Biological Sciences, Nova Southeastern University, Fort Lauderdale, FL, USA
| | - Sara A Rodriguez
- Department of Biological Sciences, Nova Southeastern University, Fort Lauderdale, FL, USA
| | - Sumayyah K Abiff
- Department of Biological Sciences, Nova Southeastern University, Fort Lauderdale, FL, USA
| | - Jaime L Tartar
- Department of Psychology and Neuroscience, Nova Southeastern University, Fort Lauderdale, FL, USA
| | - Aurélien Tartar
- Department of Biological Sciences, Nova Southeastern University, Fort Lauderdale, FL, USA.
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11
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Smith DR, Keeling PJ. Protists and the Wild, Wild West of Gene Expression: New Frontiers, Lawlessness, and Misfits. Annu Rev Microbiol 2016; 70:161-78. [PMID: 27359218 DOI: 10.1146/annurev-micro-102215-095448] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The DNA double helix has been called one of life's most elegant structures, largely because of its universality, simplicity, and symmetry. The expression of information encoded within DNA, however, can be far from simple or symmetric and is sometimes surprisingly variable, convoluted, and wantonly inefficient. Although exceptions to the rules exist in certain model systems, the true extent to which life has stretched the limits of gene expression is made clear by nonmodel systems, particularly protists (microbial eukaryotes). The nuclear and organelle genomes of protists are subject to the most tangled forms of gene expression yet identified. The complicated and extravagant picture of the underlying genetics of eukaryotic microbial life changes how we think about the flow of genetic information and the evolutionary processes shaping it. Here, we discuss the origins, diversity, and growing interest in noncanonical protist gene expression and its relationship to genomic architecture.
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Affiliation(s)
- David Roy Smith
- Department of Biology, University of Western Ontario, London, Ontario, Canada N6A 5B7;
| | - Patrick J Keeling
- Canadian Institute for Advanced Research, Department of Botany, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4;
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12
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Paz-Y-Miño-C G, Espinosa A. Kin Discrimination in Protists: From Many Cells to Single Cells and Backwards. J Eukaryot Microbiol 2016; 63:367-77. [PMID: 26873616 PMCID: PMC4856593 DOI: 10.1111/jeu.12306] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2015] [Revised: 02/03/2016] [Accepted: 02/07/2016] [Indexed: 12/16/2022]
Abstract
During four decades (1960-1990s), the conceptualization and experimental design of studies in kin recognition relied on work with multicellular eukaryotes, particularly Unikonta (including invertebrates and vertebrates) and some Bikonta (including plants). This pioneering research had an animal behavior approach. During the 2000s, work on taxa-, clone- and kin-discrimination and recognition in protists produced genetic and molecular evidence that unicellular organisms (e.g. Saccharomyces, Dictyostelium, Polysphondylium, Tetrahymena, Entamoeba and Plasmodium) could distinguish between same (self or clone) and different (diverse clones), as well as among conspecifics of close or distant genetic relatedness. Here, we discuss some of the research on the genetics of kin discrimination/recognition and highlight the scientific progress made by switching emphasis from investigating multicellular to unicellular systems (and backwards). We document how studies with protists are helping us to understand the microscopic, cellular origins and evolution of the mechanisms of kin discrimination/recognition and their significance for the advent of multicellularity. We emphasize that because protists are among the most ancient organisms on Earth, belong to multiple taxonomic groups and occupy all environments, they can be central to reexamining traditional hypotheses in the field of kin recognition, reformulating concepts, and generating new knowledge.
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Affiliation(s)
- Guillermo Paz-Y-Miño-C
- New England Center for the Public Understanding of Science, Roger Williams University, One Old Ferry Road, Bristol, Rhode Island, 02809
| | - Avelina Espinosa
- New England Center for the Public Understanding of Science, Roger Williams University, One Old Ferry Road, Bristol, Rhode Island, 02809
- Department of Biology, Roger Williams University, One Old Ferry Road, Bristol, Rhode Island, 02809
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Fiore-Donno AM, Weinert J, Wubet T, Bonkowski M. Metacommunity analysis of amoeboid protists in grassland soils. Sci Rep 2016; 6:19068. [PMID: 26750872 PMCID: PMC4707496 DOI: 10.1038/srep19068] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Accepted: 11/30/2015] [Indexed: 12/20/2022] Open
Abstract
This study reveals the diversity and distribution of two major ubiquitous groups of soil amoebae, the genus Acanthamoeba and the Myxomycetes (plasmodial slime-moulds) that are rarely, if ever, recovered in environmental sampling studies. We analyzed 150 grassland soil samples from three Biodiversity Exploratories study regions in Germany. We developed specific primers targeting the V2 variable region in the first part of the small subunit of the ribosomal RNA gene for high-throughput pyrotag sequencing. From ca. 1 million reads, applying very stringent filtering and clustering parameters to avoid overestimation of the diversity, we obtained 273 acanthamoebal and 338 myxomycete operational taxonomic units (OTUs, 96% similarity threshold). This number is consistent with the genetic diversity known in the two investigated lineages, but unequalled to date by any environmental sampling study. Only very few OTUs were identical to already known sequences. Strikingly different OTUs assemblages were found between the three German regions (PerMANOVA p.value = 0.001) and even between sites of the same region (multiple-site Simpson-based similarity indices <0.4), showing steep biogeographical gradients.
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Affiliation(s)
- Anna Maria Fiore-Donno
- Institute of Zoology, Department of Terrestrial Ecology, University of Cologne, Cologne, Germany
| | - Jan Weinert
- Institute of Zoology, Department of Terrestrial Ecology, University of Cologne, Cologne, Germany
| | - Tesfaye Wubet
- UFZ - Helmholtz Centre for Environmental Research, Department of Soil Ecology, Halle (Saale), Germany.,German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany
| | - Michael Bonkowski
- Institute of Zoology, Department of Terrestrial Ecology, University of Cologne, Cologne, Germany
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14
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Geisen S, Tveit AT, Clark IM, Richter A, Svenning MM, Bonkowski M, Urich T. Metatranscriptomic census of active protists in soils. THE ISME JOURNAL 2015; 9:2178-90. [PMID: 25822483 PMCID: PMC4579471 DOI: 10.1038/ismej.2015.30] [Citation(s) in RCA: 147] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Revised: 01/21/2015] [Accepted: 01/28/2015] [Indexed: 11/08/2022]
Abstract
The high numbers and diversity of protists in soil systems have long been presumed, but their true diversity and community composition have remained largely concealed. Traditional cultivation-based methods miss a majority of taxa, whereas molecular barcoding approaches employing PCR introduce significant biases in reported community composition of soil protists. Here, we applied a metatranscriptomic approach to assess the protist community in 12 mineral and organic soil samples from different vegetation types and climatic zones using small subunit ribosomal RNA transcripts as marker. We detected a broad diversity of soil protists spanning across all known eukaryotic supergroups and revealed a strikingly different community composition than shown before. Protist communities differed strongly between sites, with Rhizaria and Amoebozoa dominating in forest and grassland soils, while Alveolata were most abundant in peat soils. The Amoebozoa were comprised of Tubulinea, followed with decreasing abundance by Discosea, Variosea and Mycetozoa. Transcripts of Oomycetes, Apicomplexa and Ichthyosporea suggest soil as reservoir of parasitic protist taxa. Further, Foraminifera and Choanoflagellida were ubiquitously detected, showing that these typically marine and freshwater protists are autochthonous members of the soil microbiota. To the best of our knowledge, this metatranscriptomic study provides the most comprehensive picture of active protist communities in soils to date, which is essential to target the ecological roles of protists in the complex soil system.
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Affiliation(s)
- Stefan Geisen
- Department of Terrestrial Ecology, Institute of Zoology, University of Cologne, Cologne, Germany
- Department of Terrestrial Ecology, Netherlands Institute for Ecology, (NIOO-KNAW), Wageningen, The Netherlands
| | - Alexander T Tveit
- Department of Arctic and Marine Biology, UiT The Arctic University of Norway, Tromsø, Norway
| | - Ian M Clark
- Department of AgroEcology, Rothamsted Research, Harpenden, Hertfordshire, UK
| | - Andreas Richter
- Department of Microbiology and Ecosystem Sciences, University of Vienna, Vienna, Austria
| | - Mette M Svenning
- Department of Arctic and Marine Biology, UiT The Arctic University of Norway, Tromsø, Norway
| | - Michael Bonkowski
- Department of Terrestrial Ecology, Institute of Zoology, University of Cologne, Cologne, Germany
| | - Tim Urich
- Department of Ecogenomics and Systems Biology, University of Vienna, Vienna, Austria
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15
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Geisen S, Rosengarten J, Koller R, Mulder C, Urich T, Bonkowski M. Pack hunting by a common soil amoeba on nematodes. Environ Microbiol 2015; 17:4538-46. [DOI: 10.1111/1462-2920.12949] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Revised: 06/08/2015] [Accepted: 06/08/2015] [Indexed: 11/30/2022]
Affiliation(s)
- Stefan Geisen
- Department of Terrestrial Ecology; Institute of Zoology; University of Cologne; Cologne Germany
- Department of Terrestrial Ecology; Netherlands Institute of Ecology (NIOO-KNAW); Wageningen The Netherlands
| | - Jamila Rosengarten
- Department of Terrestrial Ecology; Institute of Zoology; University of Cologne; Cologne Germany
| | - Robert Koller
- Department of Terrestrial Ecology; Institute of Zoology; University of Cologne; Cologne Germany
- Forschungszentrum Jülich; IBG-2: Plant Sciences; Jülich Germany
| | - Christian Mulder
- National Institute for Public Health and the Environment (RIVM); Bilthoven The Netherlands
| | - Tim Urich
- Department of Ecogenomics and Systems Biology; University of Vienna; Vienna Austria
- Bacterial Physiology; Institute for Microbiology; Ernst Moritz Arndt University; Greifswald Germany
| | - Michael Bonkowski
- Department of Terrestrial Ecology; Institute of Zoology; University of Cologne; Cologne Germany
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16
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Speijer D, Lukeš J, Eliáš M. Sex is a ubiquitous, ancient, and inherent attribute of eukaryotic life. Proc Natl Acad Sci U S A 2015; 112:8827-34. [PMID: 26195746 PMCID: PMC4517231 DOI: 10.1073/pnas.1501725112] [Citation(s) in RCA: 171] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Sexual reproduction and clonality in eukaryotes are mostly seen as exclusive, the latter being rather exceptional. This view might be biased by focusing almost exclusively on metazoans. We analyze and discuss reproduction in the context of extant eukaryotic diversity, paying special attention to protists. We present results of phylogenetically extended searches for homologs of two proteins functioning in cell and nuclear fusion, respectively (HAP2 and GEX1), providing indirect evidence for these processes in several eukaryotic lineages where sex has not been observed yet. We argue that (i) the debate on the relative significance of sex and clonality in eukaryotes is confounded by not appropriately distinguishing multicellular and unicellular organisms; (ii) eukaryotic sex is extremely widespread and already present in the last eukaryotic common ancestor; and (iii) the general mode of existence of eukaryotes is best described by clonally propagating cell lines with episodic sex triggered by external or internal clues. However, important questions concern the relative longevity of true clonal species (i.e., species not able to return to sexual procreation anymore). Long-lived clonal species seem strikingly rare. We analyze their properties in the light of meiotic sex development from existing prokaryotic repair mechanisms. Based on these considerations, we speculate that eukaryotic sex likely developed as a cellular survival strategy, possibly in the context of internal reactive oxygen species stress generated by a (proto) mitochondrion. Thus, in the context of the symbiogenic model of eukaryotic origin, sex might directly result from the very evolutionary mode by which eukaryotic cells arose.
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Affiliation(s)
- Dave Speijer
- Department of Medical Biochemistry, Academic Medical Center, University of Amsterdam, 1105 AZ, Amsterdam, The Netherlands;
| | - Julius Lukeš
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, and Faculty of Sciences, University of South Bohemia, 370 05 České Budějovice, Czech Republic; Canadian Institute for Advanced Research, Toronto, ON, Canada M5G 1Z8
| | - Marek Eliáš
- Department of Biology and Ecology, University of Ostrava, 710 00 Ostrava, Czech Republic
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17
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Tarnawski SE, Lara E. From Environmental Sequences to Morphology: Observation and Characterisation of a Paulinellid Testate Amoeba (Micropyxidiella edaphonis gen. nov. sp. nov. Euglyphida, Paulinellidae) from Soil using Fluorescent in situ Hybridization. Protist 2015; 166:264-70. [DOI: 10.1016/j.protis.2015.04.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Revised: 04/02/2015] [Accepted: 04/06/2015] [Indexed: 10/23/2022]
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18
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Espinosa A, Paz-Y-Miño-C G. Evidence of Taxa-, Clone-, and Kin-discrimination in Protists: Ecological and Evolutionary Implications. Evol Ecol 2014; 28:1019-1029. [PMID: 25400313 DOI: 10.1007/s10682-014-9721-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Unicellular eukaryotes, or protists, are among the most ancient organisms on Earth. Protists belong to multiple taxonomic groups; they are widely distributed geographically and in all environments. Their ability to discriminate among con- and heterospecifics has been documented during the past decade. Here we discuss exemplar cases of taxa-, clone-, and possible kin-discrimination in five major lineages: Mycetozoa (Dictyostelium, Polysphondylium), Dikarya (Saccharomyces), Ciliophora (Tetrahymena), Apicomplexa (Plasmodium) and Archamoebae (Entamoeba). We summarize the proposed genetic mechanisms involved in discrimination-mediated aggregation (self versus different), including the csA, FLO and trg (formerly lag) genes, and the Proliferation Activation Factors (PAFs), which facilitate clustering in some protistan taxa. We caution about the experimental challenges intrinsic to studying recognition in protists, and highlight the opportunities for exploring the ecology and evolution of complex forms of cell-cell communication, including social behavior, in a polyphyletic, still superficially understood group of organisms. Because unicellular eukaryotes are the evolutionary precursors of multicellular life, we infer that their mechanisms of taxa-, clone-, and possible kin-discrimination gave origin to the complex diversification and sophistication of traits associated with species and kin recognition in plants, fungi, invertebrates and vertebrates.
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Affiliation(s)
- Avelina Espinosa
- Department of Biology, Roger Williams University, One Old Ferry Road, Bristol, Rhode Island 02809, USA
| | - Guillermo Paz-Y-Miño-C
- Department of Biology, University of Massachusetts Dartmouth, 285 Old Westport Road, North Dartmouth, Massachusetts 02747-2300, USA
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Abbott CL, Meyer GR. Review of Mikrocytos microcell parasites at the dawn of a new age of scientific discovery. DISEASES OF AQUATIC ORGANISMS 2014; 110:25-32. [PMID: 25060495 DOI: 10.3354/dao02788] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The genus Mikrocytos is traditionally known for Mikrocytos mackini, the microcell parasite that typically infects Pacific oysters along the west coast of North America. Multiple factors have conspired to create difficulty for scientific research on Mikrocytos parasites. These include their tiny cell size, infections that are often of light intensity, lack of suitable cell lines and techniques for in vitro culture, and the seasonal nature of infections. The extreme rate of molecular evolution in Mikrocytos stymied new species discovery and confounded attempts to resolve its phylogenetic position for many years. Fortunately, 2 recent landmark studies have paved the way forward for future research by drastically changing our understanding of the evolution and diversity of these parasites. No longer an orphan eukaryotic lineage, the phylogenetic placement of Mikrocytos has been confidently resolved within Rhizaria and as sister taxon to Haplosporidia. The genus has also found a taxonomic home within the newly-discovered order, Mikrocytida - a globally distributed lineage of parasites infecting a wide range of invertebrate hosts. Here we review available scientific information on Mikrocytos parasites including their evolution and diversity, host and geographic ranges, epizootiology, and detection of the regulated pathogen, M. mackini. We also make recommendations towards a consistent taxonomic framework for this genus by minimally suggesting the use of 18S rDNA sequence, host species information, and histopathological presentation in new species descriptions. This is timely given that we are likely embarking on a new era of scientific advancements, including species discovery, in this genus and its relatives.
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Affiliation(s)
- Cathryn L Abbott
- Department of Fisheries and Oceans, Pacific Biological Station, 3190 Hammond Bay Road, Nanaimo, BC V9T 6N7, Canada
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20
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Burki F. The eukaryotic tree of life from a global phylogenomic perspective. Cold Spring Harb Perspect Biol 2014; 6:a016147. [PMID: 24789819 DOI: 10.1101/cshperspect.a016147] [Citation(s) in RCA: 206] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Molecular phylogenetics has revolutionized our knowledge of the eukaryotic tree of life. With the advent of genomics, a new discipline of phylogenetics has emerged: phylogenomics. This method uses large alignments of tens to hundreds of genes to reconstruct evolutionary 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.
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Affiliation(s)
- Fabien Burki
- Canadian Institute for Advanced Research, Department of Botany, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
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21
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Austin P, Jarvis K. Tenth anniversary updates from our authors. BMC Biol 2013; 11:39. [PMID: 23587215 PMCID: PMC3626886 DOI: 10.1186/1741-7007-11-39] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Accepted: 04/11/2013] [Indexed: 11/10/2022] Open
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