1
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Sinha SD, Wideman JG. The persistent homology of mitochondrial ATP synthases. iScience 2023; 26:106700. [PMID: 37250340 PMCID: PMC10214729 DOI: 10.1016/j.isci.2023.106700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 01/24/2023] [Accepted: 04/14/2023] [Indexed: 05/31/2023] Open
Abstract
Relatively little is known about ATP synthase structure in protists, and the investigated ones exhibit divergent structures distinct from yeast or animals. To clarify the subunit composition of ATP synthases across all eukaryotic lineages, we used homology detection techniques and molecular modeling tools to identify an ancestral set of 17 ATP synthase subunits. Most eukaryotes possess an ATP synthase comparable to those of animals and fungi, while some have undergone drastic divergence (e.g., ciliates, myzozoans, euglenozoans). Additionally, a ∼1 billion-year-old gene fusion between ATP synthase stator subunits was identified as a synapomorphy of the SAR (Stramenopila, Alveolata, Rhizaria) supergroup (stramenopile, alveolate, rhizaria). Our comparative approach highlights the persistence of ancestral subunits even amidst major structural changes. We conclude by urging that more ATP synthase structures (e.g., from jakobids, heteroloboseans, stramenopiles, rhizarians) are needed to provide a complete picture of the evolution of the structural diversity of this ancient and essential complex.
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Affiliation(s)
- Savar D. Sinha
- Center for Mechanisms of Evolution, Biodesign Institute, School of Life Sciences, Arizona State University, Tempe, AZ 85281, USA
| | - Jeremy G. Wideman
- Center for Mechanisms of Evolution, Biodesign Institute, School of Life Sciences, Arizona State University, Tempe, AZ 85281, USA
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2
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Bremer N, Tria FDK, Skejo J, Martin WF. The Ancestral Mitotic State: Closed Orthomitosis With Intranuclear Spindles in the Syncytial Last Eukaryotic Common Ancestor. Genome Biol Evol 2023; 15:7031494. [PMID: 36752808 PMCID: PMC9985178 DOI: 10.1093/gbe/evad016] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 01/26/2023] [Accepted: 02/03/2023] [Indexed: 02/09/2023] Open
Abstract
All eukaryotes have linear chromosomes that are distributed to daughter nuclei during mitotic division, but the ancestral state of nuclear division in the last eukaryotic common ancestor (LECA) is so far unresolved. To address this issue, we have employed ancestral state reconstructions for mitotic states that can be found across the eukaryotic tree concerning the intactness of the nuclear envelope during mitosis (open or closed), the position of spindles (intranuclear or extranuclear), and the symmetry of spindles being either axial (orthomitosis) or bilateral (pleuromitosis). The data indicate that the LECA possessed closed orthomitosis with intranuclear spindles. Our reconstruction is compatible with recent findings indicating a syncytial state of the LECA, because it decouples three main processes: chromosome division, chromosome partitioning, and cell division (cytokinesis). The possession of closed mitosis using intranuclear spindles adds to the number of cellular traits that can now be attributed to LECA, providing insights into the lifestyle of this otherwise elusive biological entity at the origin of eukaryotic cells. Closed mitosis in a syncytial eukaryotic common ancestor would buffer mutations arising at the origin of mitotic division by allowing nuclei with viable chromosome sets to complement defective nuclei via mRNA in the cytosol.
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Affiliation(s)
- Nico Bremer
- Institute for Molecular Evolution, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Fernando D K Tria
- Institute for Molecular Evolution, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Josip Skejo
- Institute for Molecular Evolution, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - William F Martin
- Institute for Molecular Evolution, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
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3
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Chang S, Buswell J. Medicinal Mushrooms: Past, Present and Future. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2023; 184:1-27. [PMID: 35220455 DOI: 10.1007/10_2021_197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The survival of Homo sapiens is continually under threat from agencies capable of inflicting calamitous damage to the overall health and well-being of humankind. One strategy aimed at combatting this threat is focused on medicinal mushrooms and derivatives thereof. Mushrooms themselves have been consumed as part of the human diet for centuries, whereas 'mushroom nutriceuticals' is a more recently adopted term describing mushroom-derived products taken as dietary supplements to enhance general health and fitness. Among the most extensively studied pharmacologically active components of mushrooms are polysaccharides and polysaccharide-protein complexes, triterpenes, lectins, and fungal immunomodulatory proteins. Medicinal mushrooms have been credited with a wide range of therapeutic properties including antitumour/anti-cancer, antioxidant, hepatoprotective, anti-diabetic, antimicrobial, cholesterol-lowering and genoprotective activities as well as protection against atherosclerosis, cardiovascular, chronic inflammatory and autoimmune diseases, and neurodegenerative conditions. This review examines the past, present and future of medicinal mushroom development including the two legs concept for the mushroom industry and the pyramid model summarizing the various human applications of mushrooms. It considers numerous issues the industry needs to address to exploit fully the opportunities presented by the continued increasing demand for medicinal mushrooms, and by the future overall expansion of the medicinal mushroom movement.
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Affiliation(s)
- Shuting Chang
- Department of Biology, The Chinese University of Hong Kong, Shatin, New Territories, China
| | - John Buswell
- Institute of Edible Fungi, Shanghai Academy of Agricultural Sciences, Shanghai, China
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4
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Cerón-Romero MA, Fonseca MM, de Oliveira Martins L, Posada D, Katz LA. Phylogenomic Analyses of 2,786 Genes in 158 Lineages Support a Root of the Eukaryotic Tree of Life between Opisthokonts and All Other Lineages. Genome Biol Evol 2022; 14:evac119. [PMID: 35880421 PMCID: PMC9366629 DOI: 10.1093/gbe/evac119] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/11/2022] [Indexed: 12/02/2022] Open
Abstract
Advances in phylogenomics and high-throughput sequencing have allowed the reconstruction of deep phylogenetic relationships in the evolution of eukaryotes. Yet, the root of the eukaryotic tree of life remains elusive. The most popular hypothesis in textbooks and reviews is a root between Unikonta (Opisthokonta + Amoebozoa) and Bikonta (all other eukaryotes), which emerged from analyses of a single-gene fusion. Subsequent, highly cited studies based on concatenation of genes supported this hypothesis with some variations or proposed a root within Excavata. However, concatenation of genes does not consider phylogenetically-informative events like gene duplications and losses. A recent study using gene tree parsimony (GTP) suggested the root lies between Opisthokonta and all other eukaryotes, but only including 59 taxa and 20 genes. Here we use GTP with a duplication-loss model in a gene-rich and taxon-rich dataset (i.e., 2,786 gene families from two sets of 155 and 158 diverse eukaryotic lineages) to assess the root, and we iterate each analysis 100 times to quantify tree space uncertainty. We also contrasted our results and discarded alternative hypotheses from the literature using GTP and the likelihood-based method SpeciesRax. Our estimates suggest a root between Fungi or Opisthokonta and all other eukaryotes; but based on further analysis of genome size, we propose that the root between Opisthokonta and all other eukaryotes is the most likely.
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Affiliation(s)
- Mario A Cerón-Romero
- Department of Biological Sciences, Smith College, Northampton, Massachusetts, USA
- Program in Organismic and Evolutionary Biology, University of Massachusetts Amherst, Amherst, Massachusetts, USA
- Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana-Champaign, Illinois, USA
| | - Miguel M Fonseca
- CIIMAR - Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Porto, Portugal
| | - Leonardo de Oliveira Martins
- Department of Biochemistry, Genetics and Immunology, University of Vigo, 36310 Vigo, Spain
- Quadram Institute Bioscience, Norwich, United Kingdom
| | - David Posada
- Department of Biochemistry, Genetics and Immunology, University of Vigo, 36310 Vigo, Spain
- CINBIO, Universidade de Vigo, 36310 Vigo, Spain
- Galicia Sur Health Research Institute (IIS Galicia Sur), SERGAS-UVIGO, Vigo, Spain
| | - Laura A Katz
- Department of Biological Sciences, Smith College, Northampton, Massachusetts, USA
- Program in Organismic and Evolutionary Biology, University of Massachusetts Amherst, Amherst, Massachusetts, USA
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5
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Bremer N, Knopp M, Martin WF, Tria FDK. Realistic Gene Transfer to Gene Duplication Ratios Identify Different Roots in the Bacterial Phylogeny Using a Tree Reconciliation Method. LIFE (BASEL, SWITZERLAND) 2022; 12:life12070995. [PMID: 35888084 PMCID: PMC9322720 DOI: 10.3390/life12070995] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 06/29/2022] [Accepted: 07/01/2022] [Indexed: 11/29/2022]
Abstract
The rooting of phylogenetic trees permits important inferences about ancestral states and the polarity of evolutionary events. Recently, methods that reconcile discordance between gene-trees and species-trees—tree reconciliation methods—are becoming increasingly popular for rooting species trees. Rooting via reconciliation requires values for a particular parameter, the gene transfer to gene duplication ratio (T:D), which in current practice is estimated on the fly from discordances observed in the trees. To date, the accuracy of T:D estimates obtained by reconciliation analyses has not been compared to T:D estimates obtained by independent means, hence the effect of T:D upon inferences of species tree roots is altogether unexplored. Here we investigated the issue in detail by performing tree reconciliations of more than 10,000 gene trees under a variety of T:D ratios for two phylogenetic cases: a bacterial (prokaryotic) tree with 265 species and a fungal-metazoan (eukaryotic) tree with 31 species. We show that the T:D ratios automatically estimated by a current tree reconciliation method, ALE, generate virtually identical T:D ratios across bacterial genes and fungal-metazoan genes. The T:D ratios estimated by ALE differ 10- to 100-fold from robust, ALE-independent estimates from real data. More important is our finding that the root inferences using ALE in both datasets are strongly dependent upon T:D. Using more realistic T:D ratios, the number of roots inferred by ALE consistently increases and, in some cases, clearly incorrect roots are inferred. Furthermore, our analyses reveal that gene duplications have a far greater impact on ALE’s preferences for phylogenetic root placement than gene transfers or gene losses do. Overall, we show that obtaining reliable species tree roots with ALE is only possible when gene duplications are abundant in the data and the number of falsely inferred gene duplications is low. Finding a sufficient sample of true gene duplications for rooting species trees critically depends on the T:D ratios used in the analyses. T:D ratios, while being important parameters of genome evolution in their own right, affect the root inferences with tree reconciliations to an unanticipated degree.
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6
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Spang A, Mahendrarajah TA, Offre P, Stairs CW. Evolving perspective on the origin and diversification of cellular life and the virosphere. Genome Biol Evol 2022; 14:6537539. [PMID: 35218347 PMCID: PMC9169541 DOI: 10.1093/gbe/evac034] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/18/2022] [Indexed: 11/14/2022] Open
Abstract
The tree of life (TOL) is a powerful framework to depict the evolutionary history of cellular organisms through time, from our microbial origins to the diversification of multicellular eukaryotes that shape the visible biosphere today. During the past decades, our perception of the TOL has fundamentally changed, in part, due to profound methodological advances, which allowed a more objective approach to studying organismal and viral diversity and led to the discovery of major new branches in the TOL as well as viral lineages. Phylogenetic and comparative genomics analyses of these data have, among others, revolutionized our understanding of the deep roots and diversity of microbial life, the origin of the eukaryotic cell, eukaryotic diversity, as well as the origin, and diversification of viruses. In this review, we provide an overview of some of the recent discoveries on the evolutionary history of cellular organisms and their viruses and discuss a variety of complementary techniques that we consider crucial for making further progress in our understanding of the TOL and its interconnection with the virosphere.
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Affiliation(s)
- Anja Spang
- NIOZ, Royal Netherlands Institute for Sea Research, Department of Marine Microbiology and Biogeochemistry, Utrecht University, The Netherlands and 1790 AB Den Burg.,Department of Cell- and Molecular Biology, Science for Life Laboratory, Uppsala University, Sweden SE-75123, Uppsala
| | - Tara A Mahendrarajah
- NIOZ, Royal Netherlands Institute for Sea Research, Department of Marine Microbiology and Biogeochemistry, Utrecht University, The Netherlands and 1790 AB Den Burg
| | - Pierre Offre
- NIOZ, Royal Netherlands Institute for Sea Research, Department of Marine Microbiology and Biogeochemistry, Utrecht University, The Netherlands and 1790 AB Den Burg
| | - Courtney W Stairs
- Department of Biology, Lund University, Sweden Sölvegatan 35, 223 62 Lund
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7
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Weiner AKM, Cerón-Romero MA, Yan Y, Katz LA. Phylogenomics of the Epigenetic Toolkit Reveals Punctate Retention of Genes across Eukaryotes. Genome Biol Evol 2021; 12:2196-2210. [PMID: 33049043 DOI: 10.1093/gbe/evaa198] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/15/2020] [Indexed: 12/17/2022] Open
Abstract
Epigenetic processes in eukaryotes play important roles through regulation of gene expression, chromatin structure, and genome rearrangements. The roles of chromatin modification (e.g., DNA methylation and histone modification) and non-protein-coding RNAs have been well studied in animals and plants. With the exception of a few model organisms (e.g., Saccharomyces and Plasmodium), much less is known about epigenetic toolkits across the remainder of the eukaryotic tree of life. Even with limited data, previous work suggested the existence of an ancient epigenetic toolkit in the last eukaryotic common ancestor. We use PhyloToL, our taxon-rich phylogenomic pipeline, to detect homologs of epigenetic genes and evaluate their macroevolutionary patterns among eukaryotes. In addition to data from GenBank, we increase taxon sampling from understudied clades of SAR (Stramenopila, Alveolata, and Rhizaria) and Amoebozoa by adding new single-cell transcriptomes from ciliates, foraminifera, and testate amoebae. We focus on 118 gene families, 94 involved in chromatin modification and 24 involved in non-protein-coding RNA processes based on the epigenetics literature. Our results indicate 1) the presence of a large number of epigenetic gene families in the last eukaryotic common ancestor; 2) differential conservation among major eukaryotic clades, with a notable paucity of genes within Excavata; and 3) punctate distribution of epigenetic gene families between species consistent with rapid evolution leading to gene loss. Together these data demonstrate the power of taxon-rich phylogenomic studies for illuminating evolutionary patterns at scales of >1 billion years of evolution and suggest that macroevolutionary phenomena, such as genome conflict, have shaped the evolution of the eukaryotic epigenetic toolkit.
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Affiliation(s)
- Agnes K M Weiner
- Department of Biological Sciences, Smith College, Northampton, Massachusetts
| | - Mario A Cerón-Romero
- Department of Biological Sciences, Smith College, Northampton, Massachusetts.,Program in Organismic and Evolutionary Biology, University of Massachusetts Amherst
| | - Ying Yan
- Department of Biological Sciences, Smith College, Northampton, Massachusetts
| | - Laura A Katz
- Department of Biological Sciences, Smith College, Northampton, Massachusetts.,Program in Organismic and Evolutionary Biology, University of Massachusetts Amherst
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8
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Coleman GA, Davín AA, Mahendrarajah TA, Szánthó LL, Spang A, Hugenholtz P, Szöllősi GJ, Williams TA. A rooted phylogeny resolves early bacterial evolution. Science 2021; 372:372/6542/eabe0511. [PMID: 33958449 DOI: 10.1126/science.abe0511] [Citation(s) in RCA: 89] [Impact Index Per Article: 29.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 11/05/2020] [Accepted: 04/01/2021] [Indexed: 12/17/2022]
Abstract
A rooted bacterial tree is necessary to understand early evolution, but the position of the root is contested. Here, we model the evolution of 11,272 gene families to identify the root, extent of horizontal gene transfer (HGT), and the nature of the last bacterial common ancestor (LBCA). Our analyses root the tree between the major clades Terrabacteria and Gracilicutes and suggest that LBCA was a free-living flagellated, rod-shaped double-membraned organism. Contrary to recent proposals, our analyses reject a basal placement of the Candidate Phyla Radiation, which instead branches sister to Chloroflexota within Terrabacteria. While most gene families (92%) have evidence of HGT, overall, two-thirds of gene transmissions have been vertical, suggesting that a rooted tree provides a meaningful frame of reference for interpreting bacterial evolution.
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Affiliation(s)
- Gareth A Coleman
- School of Biological Sciences, University of Bristol, Bristol BS8 1TQ, UK
| | - Adrián A Davín
- Australian Centre for Ecogenomics, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Tara A Mahendrarajah
- Department of Marine Microbiology and Biogeochemistry, NIOZ, Royal Netherlands Institute for Sea Research, 1790 AB Den Burg, Netherlands
| | - Lénárd L Szánthó
- Department of Biological Physics, Eötvös Loránd University, 1117 Budapest, Hungary.,MTA-ELTE "Lendület" Evolutionary Genomics Research Group, 1117 Budapest, Hungary
| | - Anja Spang
- Department of Marine Microbiology and Biogeochemistry, NIOZ, Royal Netherlands Institute for Sea Research, 1790 AB Den Burg, Netherlands.,Department of Cell- and Molecular Biology, Uppsala University, SE-75123 Uppsala, Sweden
| | - Philip Hugenholtz
- Australian Centre for Ecogenomics, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland 4072, Australia.
| | - Gergely J Szöllősi
- Department of Biological Physics, Eötvös Loránd University, 1117 Budapest, Hungary. .,MTA-ELTE "Lendület" Evolutionary Genomics Research Group, 1117 Budapest, Hungary.,Institute of Evolution, Centre for Ecological Research, 1121 Budapest, Hungary
| | - Tom A Williams
- School of Biological Sciences, University of Bristol, Bristol BS8 1TQ, UK.
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9
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Derbyshire EJ, Delange J. Fungal Protein – What Is It and What Is the Health Evidence? A Systematic Review Focusing on Mycoprotein. FRONTIERS IN SUSTAINABLE FOOD SYSTEMS 2021. [DOI: 10.3389/fsufs.2021.581682] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Mycoprotein is a protein-rich fungal-derived sustainable food source that was first discovered in the early 1960's. Since then, a sizeable body of research has investigated the health benefits of mycelium protein. Given this, the present publication aims to systematically review the effects of mycoprotein on human health. A literature search of human studies was conducted using PubMed Central, ClinicalTrials.Gov, Google Scholar and a manual search. Sixteen controlled trials, totaling 432 participants were included – of these 5 studies reported total cholesterol, 5 reported on energy intake, 7 on insulin levels, 8 on glucose levels and 4 studied protein response. Risk of bias showed that 7 studies were good quality although heterogeneity was apparent between studies. Results showed that acute mycoprotein ingestion was associated with reduced total cholesterol levels, particularly amongst those with hyperlipidemia. Evidence was less conclusive for effects on blood glucose and insulin levels. Mycoprotein also appears to be a promising bioavailable source of essential amino acids that could induce muscle protein synthesis. Overall, given growing interest in sustainable proteins and accruing health evidence for mycoprotein, firmer embedment with food-based dietary guidelines is now worthy of consideration.
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10
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Abstract
Phagocytosis, or 'cell eating', is a eukaryote-specific process where particulate matter is engulfed via invaginations of the plasma membrane. The origin of phagocytosis has been central to discussions on eukaryogenesis for decades-, where it is argued as being either a prerequisite for, or consequence of, the acquisition of the ancestral mitochondrion. Recently, genomic and cytological evidence has increasingly supported the view that the pre-mitochondrial host cell-a bona fide archaeon branching within the 'Asgard' archaea-was incapable of phagocytosis and used alternative mechanisms to incorporate the alphaproteobacterial ancestor of mitochondria. Indeed, the diversity and variability of proteins associated with phagosomes across the eukaryotic tree suggest that phagocytosis, as seen in a variety of extant eukaryotes, may have evolved independently several times within the eukaryotic crown-group. Since phagocytosis is critical to the functioning of modern marine food webs (without it, there would be no microbial loop or animal life), multiple late origins of phagocytosis could help explain why many of the ecological and evolutionary innovations of the Neoproterozoic Era (e.g. the advent of eukaryotic biomineralization, the 'Rise of Algae' and the origin of animals) happened when they did.
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Affiliation(s)
- Daniel B. Mills
- Department of Geological Sciences, Stanford University, Stanford, CA 94305, USA
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11
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Wade T, Rangel LT, Kundu S, Fournier GP, Bansal MS. Assessing the accuracy of phylogenetic rooting methods on prokaryotic gene families. PLoS One 2020; 15:e0232950. [PMID: 32413061 PMCID: PMC7228096 DOI: 10.1371/journal.pone.0232950] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Accepted: 04/24/2020] [Indexed: 12/18/2022] Open
Abstract
Almost all standard phylogenetic methods for reconstructing gene trees result in unrooted trees; yet, many of the most useful applications of gene trees require that the gene trees be correctly rooted. As a result, several computational methods have been developed for inferring the root of unrooted gene trees. However, the accuracy of such methods has never been systematically evaluated on prokaryotic gene families, where horizontal gene transfer is often one of the dominant evolutionary events driving gene family evolution. In this work, we address this gap by conducting a thorough comparative evaluation of five different rooting methods using large collections of both simulated and empirical prokaryotic gene trees. Our simulation study is based on 6000 true and reconstructed gene trees on 100 species and characterizes the rooting accuracy of the four methods under 36 different evolutionary conditions and 3 levels of gene tree reconstruction error. The empirical study is based on a large, carefully designed data set of 3098 gene trees from 504 bacterial species (406 Alphaproteobacteria and 98 Cyanobacteria) and reveals insights that supplement those gleaned from the simulation study. Overall, this work provides several valuable insights into the accuracy of the considered methods that will help inform the choice of rooting methods to use when studying microbial gene family evolution. Among other findings, this study identifies parsimonious Duplication-Transfer-Loss (DTL) rooting and Minimal Ancestor Deviation (MAD) rooting as two of the most accurate gene tree rooting methods for prokaryotes and specifies the evolutionary conditions under which these methods are most accurate, demonstrates that DTL rooting is highly sensitive to high evolutionary rates and gene tree error, and that rooting methods based on branch-lengths are generally robust to gene tree reconstruction error.
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Affiliation(s)
- Taylor Wade
- Department of Computer Science & Engineering, University of Connecticut, Storrs, CT, United States of America
| | - L. Thiberio Rangel
- Department of Earth, Atmospheric & Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, United States of America
| | - Soumya Kundu
- Department of Computer Science & Engineering, University of Connecticut, Storrs, CT, United States of America
| | - Gregory P. Fournier
- Department of Earth, Atmospheric & Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, United States of America
| | - Mukul S. Bansal
- Department of Computer Science & Engineering, University of Connecticut, Storrs, CT, United States of America
- Institute for Systems Genomics, University of Connecticut, Storrs, CT, United States of America
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12
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Stadler PF, Geiß M, Schaller D, López Sánchez A, González Laffitte M, Valdivia DI, Hellmuth M, Hernández Rosales M. From pairs of most similar sequences to phylogenetic best matches. Algorithms Mol Biol 2020; 15:5. [PMID: 32308731 PMCID: PMC7147060 DOI: 10.1186/s13015-020-00165-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 03/26/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Many of the commonly used methods for orthology detection start from mutually most similar pairs of genes (reciprocal best hits) as an approximation for evolutionary most closely related pairs of genes (reciprocal best matches). This approximation of best matches by best hits becomes exact for ultrametric dissimilarities, i.e., under the Molecular Clock Hypothesis. It fails, however, whenever there are large lineage specific rate variations among paralogous genes. In practice, this introduces a high level of noise into the input data for best-hit-based orthology detection methods. RESULTS If additive distances between genes are known, then evolutionary most closely related pairs can be identified by considering certain quartets of genes provided that in each quartet the outgroup relative to the remaining three genes is known. A priori knowledge of underlying species phylogeny greatly facilitates the identification of the required outgroup. Although the workflow remains a heuristic since the correct outgroup cannot be determined reliably in all cases, simulations with lineage specific biases and rate asymmetries show that nearly perfect results can be achieved. In a realistic setting, where distances data have to be estimated from sequence data and hence are noisy, it is still possible to obtain highly accurate sets of best matches. CONCLUSION Improvements of tree-free orthology assessment methods can be expected from a combination of the accurate inference of best matches reported here and recent mathematical advances in the understanding of (reciprocal) best match graphs and orthology relations. AVAILABILITY Accompanying software is available at https://github.com/david-schaller/AsymmeTree.
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Affiliation(s)
- Peter F. Stadler
- Bioinformatics Group, Department of Computer Science, and Interdisciplinary Center for Bioinformatics, Universität Leipzig, Härtelstraße 16–18, 04107 Leipzig, Germany
- Competence Center for Scalable Data Services and Solutions Dresden/Leipzig, Interdisciplinary Center for Bioinformatics, German Centre for Integrative Biodiversity Research (iDiv), and Leipzig Research Center for Civilization Diseases, Universität Leipzig, Augustusplatz 12, 04107 Leipzig, Germany
- Max Planck Institute for Mathematics in the Sciences, Inselstraße 22, 04103 Leipzig, Germany
- Department of Theoretical Chemistry, University of Vienna, Währinger Straße 17, 1090 Vienna, Austria
- Facultad de Ciencias, Universidad National de Colombia, Sede Bogotá, Ciudad Universitaria, 111321 Bogotá, D.C. Colombia
- Santa Fe Institute, 1399 Hyde Park Rd., Santa Fe, NM87501 USA
| | - Manuela Geiß
- Bioinformatics Group, Department of Computer Science, and Interdisciplinary Center for Bioinformatics, Universität Leipzig, Härtelstraße 16–18, 04107 Leipzig, Germany
- Software Competence Center Hagenberg GmbH, Softwarepark 21, 4232 Hagenberg, Austria
| | - David Schaller
- Bioinformatics Group, Department of Computer Science, and Interdisciplinary Center for Bioinformatics, Universität Leipzig, Härtelstraße 16–18, 04107 Leipzig, Germany
| | - Alitzel López Sánchez
- CONACYT-Instituto de Matemáticas, UNAM Juriquilla, Blvd. Juriquilla 3001, 76230 Juriquilla, Querétaro, QRO México
| | - Marcos González Laffitte
- CONACYT-Instituto de Matemáticas, UNAM Juriquilla, Blvd. Juriquilla 3001, 76230 Juriquilla, Querétaro, QRO México
| | - Dulce I. Valdivia
- Departamento de Ingeniería Genética, Centro de Investigación y de Estudios Avanzados del IPN (CINVESTAV), Km. 9.6 Libramiento Norte Carretera Irapuato-León, 36821 Irapuato, GTO México
| | - Marc Hellmuth
- School of Computing, University of Leeds, E C Stoner Building, Leeds, LS2 9JT UK
| | - Maribel Hernández Rosales
- CONACYT-Instituto de Matemáticas, UNAM Juriquilla, Blvd. Juriquilla 3001, 76230 Juriquilla, Querétaro, QRO México
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13
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Burki F, Roger AJ, Brown MW, Simpson AGB. The New Tree of Eukaryotes. Trends Ecol Evol 2019; 35:43-55. [PMID: 31606140 DOI: 10.1016/j.tree.2019.08.008] [Citation(s) in RCA: 396] [Impact Index Per Article: 79.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 08/15/2019] [Accepted: 08/15/2019] [Indexed: 01/01/2023]
Abstract
For 15 years, the eukaryote Tree of Life (eToL) has been divided into five to eight major groupings, known as 'supergroups'. However, the tree has been profoundly rearranged during this time. The new eToL results from the widespread application of phylogenomics and numerous discoveries of major lineages of eukaryotes, mostly free-living heterotrophic protists. The evidence that supports the tree has transitioned from a synthesis of molecular phylogenetics and biological characters to purely molecular phylogenetics. Most current supergroups lack defining morphological or cell-biological characteristics, making the supergroup label even more arbitrary than before. Going forward, the combination of traditional culturing with maturing culture-free approaches and phylogenomics should accelerate the process of completing and resolving the eToL at its deepest levels.
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Affiliation(s)
- Fabien Burki
- Department of Organismal Biology, Program in Systematic Biology, Uppsala University, Uppsala, Sweden; Science for Life Laboratory, Uppsala University, Uppsala, Sweden.
| | - Andrew J Roger
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS, Canada; Centre for Comparative Genomics and Evolutionary Bioinformatics, Dalhousie University, Halifax, NS, Canada
| | - Matthew W Brown
- Department of Biological Sciences, Mississippi State University, Mississippi State, MS, USA; Institute for Genomics, Biocomputing, and Biotechnology, Mississippi State University, Mississippi State, MS, USA
| | - Alastair G B Simpson
- Centre for Comparative Genomics and Evolutionary Bioinformatics, Dalhousie University, Halifax, NS, Canada; Department of Biology, Dalhousie University, Halifax, NS, Canada.
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14
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Deutekom ES, Vosseberg J, van Dam TJP, Snel B. Measuring the impact of gene prediction on gene loss estimates in Eukaryotes by quantifying falsely inferred absences. PLoS Comput Biol 2019; 15:e1007301. [PMID: 31461468 PMCID: PMC6736253 DOI: 10.1371/journal.pcbi.1007301] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 09/10/2019] [Accepted: 08/01/2019] [Indexed: 12/25/2022] Open
Abstract
In recent years it became clear that in eukaryotic genome evolution gene loss is prevalent over gene gain. However, the absence of genes in an annotated genome is not always equivalent to the loss of genes. Due to sequencing issues, or incorrect gene prediction, genes can be falsely inferred as absent. This implies that loss estimates are overestimated and, more generally, that falsely inferred absences impact genomic comparative studies. However, reliable estimates of how prevalent this issue is are lacking. Here we quantified the impact of gene prediction on gene loss estimates in eukaryotes by analysing 209 phylogenetically diverse eukaryotic organisms and comparing their predicted proteomes to that of their respective six-frame translated genomes. We observe that 4.61% of domains per species were falsely inferred to be absent for Pfam domains predicted to have been present in the last eukaryotic common ancestor. Between phylogenetically different categories this estimate varies substantially: for clade-specific loss (ancestral loss) we found 1.30% and for species-specific loss 16.88% to be falsely inferred as absent. For BUSCO 1-to-1 orthologous families, 18.30% were falsely inferred to be absent. Finally, we showed that falsely inferred absences indeed impact loss estimates, with the number of losses decreasing by 11.78%. Our work strengthens the increasing number of studies showing that gene loss is an important factor in eukaryotic genome evolution. However, while we demonstrate that on average inferring gene absences from predicted proteomes is reliable, caution is warranted when inferring species-specific absences.
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Affiliation(s)
- Eva S. Deutekom
- Theoretical Biology and Bioinformatics, Department of Biology, Science faculty, Utrecht University, Utrecht, The Netherlands
| | - Julian Vosseberg
- Theoretical Biology and Bioinformatics, Department of Biology, Science faculty, Utrecht University, Utrecht, The Netherlands
| | - Teunis J. P. van Dam
- Theoretical Biology and Bioinformatics, Department of Biology, Science faculty, Utrecht University, Utrecht, The Netherlands
| | - Berend Snel
- Theoretical Biology and Bioinformatics, Department of Biology, Science faculty, Utrecht University, Utrecht, The Netherlands
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15
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Was the Mitochondrion Necessary to Start Eukaryogenesis? Trends Microbiol 2018; 27:96-104. [PMID: 30466901 DOI: 10.1016/j.tim.2018.10.005] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 09/21/2018] [Accepted: 10/11/2018] [Indexed: 12/11/2022]
Abstract
Arguments based on cell energetics favour the view that a mitochondrion capable of oxidative phosphorylation was a prerequisite for the evolution of other features of the eukaryotic cell, including increased volume, genome size and, eventually, phagotrophy. Contrary to this we argue that: (i) extant amitochondriate eukaryotes possess voluminous phagotrophic cells with large genomes; (ii) picoeukaryotes demonstrate that phagotrophy is feasible at prokaryotic cell sizes; and (iii) the assumption that evolution of complex features requires extra ATP, often mentioned in this context, is unfounded and should not be used in such considerations. We claim that the diversity of cell organisations and functions observed today in eukaryotes gives no reason to postulate that a mitochondrion must have preceded phagocytosis in eukaryogenesis.
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16
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Hemimastigophora is a novel supra-kingdom-level lineage of eukaryotes. Nature 2018; 564:410-414. [PMID: 30429611 DOI: 10.1038/s41586-018-0708-8] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Accepted: 09/21/2018] [Indexed: 12/11/2022]
Abstract
Almost all eukaryote life forms have now been placed within one of five to eight supra-kingdom-level groups using molecular phylogenetics1-4. The 'phylum' Hemimastigophora is probably the most distinctive morphologically defined lineage that still awaits such a phylogenetic assignment. First observed in the nineteenth century, hemimastigotes are free-living predatory protists with two rows of flagella and a unique cell architecture5-7; to our knowledge, no molecular sequence data or cultures are currently available for this group. Here we report phylogenomic analyses based on high-coverage, cultivation-independent transcriptomics that place Hemimastigophora outside of all established eukaryote supergroups. They instead comprise an independent supra-kingdom-level lineage that most likely forms a sister clade to the 'Diaphoretickes' half of eukaryote diversity (that is, the 'stramenopiles, alveolates and Rhizaria' supergroup (Sar), Archaeplastida and Cryptista, as well as other major groups). The previous ranking of Hemimastigophora as a phylum understates the evolutionary distinctiveness of this group, which has considerable importance for investigations into the deep-level evolutionary history of eukaryotic life-ranging from understanding the origins of fundamental cell systems to placing the root of the tree. We have also established the first culture of a hemimastigote (Hemimastix kukwesjijk sp. nov.), which will facilitate future genomic and cell-biological investigations into eukaryote evolution and the last eukaryotic common ancestor.
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17
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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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18
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Záhonová K, Petrželková R, Valach M, Yazaki E, Tikhonenkov DV, Butenko A, Janouškovec J, Hrdá Š, Klimeš V, Burger G, Inagaki Y, Keeling PJ, Hampl V, Flegontov P, Yurchenko V, Eliáš M. Extensive molecular tinkering in the evolution of the membrane attachment mode of the Rheb GTPase. Sci Rep 2018; 8:5239. [PMID: 29588502 PMCID: PMC5869587 DOI: 10.1038/s41598-018-23575-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 03/15/2018] [Indexed: 02/07/2023] Open
Abstract
Rheb is a conserved and widespread Ras-like GTPase involved in cell growth regulation mediated by the (m)TORC1 kinase complex and implicated in tumourigenesis in humans. Rheb function depends on its association with membranes via prenylated C-terminus, a mechanism shared with many other eukaryotic GTPases. Strikingly, our analysis of a phylogenetically rich sample of Rheb sequences revealed that in multiple lineages this canonical and ancestral membrane attachment mode has been variously altered. The modifications include: (1) accretion to the N-terminus of two different phosphatidylinositol 3-phosphate-binding domains, PX in Cryptista (the fusion being the first proposed synapomorphy of this clade), and FYVE in Euglenozoa and the related undescribed flagellate SRT308; (2) acquisition of lipidic modifications of the N-terminal region, namely myristoylation and/or S-palmitoylation in seven different protist lineages; (3) acquisition of S-palmitoylation in the hypervariable C-terminal region of Rheb in apusomonads, convergently to some other Ras family proteins; (4) replacement of the C-terminal prenylation motif with four transmembrane segments in a novel Rheb paralog in the SAR clade; (5) loss of an evident C-terminal membrane attachment mechanism in Tremellomycetes and some Rheb paralogs of Euglenozoa. Rheb evolution is thus surprisingly dynamic and presents a spectacular example of molecular tinkering.
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Affiliation(s)
- Kristína Záhonová
- Department of Biology and Ecology & Institute of Environmental Technologies, Faculty of Science, University of Ostrava, Ostrava, Czech Republic
| | - Romana Petrželková
- Department of Biology and Ecology & Institute of Environmental Technologies, Faculty of Science, University of Ostrava, Ostrava, Czech Republic
| | - Matus Valach
- Department of Biochemistry and Robert-Cedergren Centre for Bioinformatics and Genomics, Université de Montréal, Montreal, Canada
| | - Euki Yazaki
- Institute for Biological Sciences, University of Tsukuba, Tsukuba, Japan
| | - Denis V Tikhonenkov
- Laboratory of Microbiology, Papanin Institute for Biology of Inland Waters, Russian Academy of Sciences, Borok, Russia
| | - Anzhelika Butenko
- Department of Biology and Ecology & Institute of Environmental Technologies, Faculty of Science, University of Ostrava, Ostrava, Czech Republic
| | - Jan Janouškovec
- Department of Genetics, Evolution and Environment, University College London, London, United Kingdom
| | - Štěpánka Hrdá
- Department of Parasitology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Vladimír Klimeš
- Department of Biology and Ecology & Institute of Environmental Technologies, Faculty of Science, University of Ostrava, Ostrava, Czech Republic
| | - Gertraud Burger
- Department of Biochemistry and Robert-Cedergren Centre for Bioinformatics and Genomics, Université de Montréal, Montreal, Canada
| | - Yuji Inagaki
- Center for Computational Sciences, University of Tsukuba, Tsukuba, Japan
| | - Patrick J Keeling
- Department of Botany, University of British Columbia, Vancouver, Canada
| | - Vladimír Hampl
- Department of Parasitology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Pavel Flegontov
- Department of Biology and Ecology & Institute of Environmental Technologies, Faculty of Science, University of Ostrava, Ostrava, Czech Republic
| | - Vyacheslav Yurchenko
- Department of Biology and Ecology & Institute of Environmental Technologies, Faculty of Science, University of Ostrava, Ostrava, Czech Republic
| | - Marek Eliáš
- Department of Biology and Ecology & Institute of Environmental Technologies, Faculty of Science, University of Ostrava, Ostrava, Czech Republic.
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19
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Radzvilavicius AL, Blackstone NW. The evolution of individuality revisited. Biol Rev Camb Philos Soc 2018; 93:1620-1633. [DOI: 10.1111/brv.12412] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2017] [Revised: 02/21/2018] [Accepted: 02/28/2018] [Indexed: 12/28/2022]
Affiliation(s)
| | - Neil W. Blackstone
- Department of Biological Sciences; Northern Illinois University; DeKalb IL 60115 U.S.A
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20
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Mai U, Sayyari E, Mirarab S. Minimum variance rooting of phylogenetic trees and implications for species tree reconstruction. PLoS One 2017; 12:e0182238. [PMID: 28800608 PMCID: PMC5553649 DOI: 10.1371/journal.pone.0182238] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Accepted: 06/25/2017] [Indexed: 12/29/2022] Open
Abstract
Phylogenetic trees inferred using commonly-used models of sequence evolution are unrooted, but the root position matters both for interpretation and downstream applications. This issue has been long recognized; however, whether the potential for discordance between the species tree and gene trees impacts methods of rooting a phylogenetic tree has not been extensively studied. In this paper, we introduce a new method of rooting a tree based on its branch length distribution; our method, which minimizes the variance of root to tip distances, is inspired by the traditional midpoint rerooting and is justified when deviations from the strict molecular clock are random. Like midpoint rerooting, the method can be implemented in a linear time algorithm. In extensive simulations that consider discordance between gene trees and the species tree, we show that the new method is more accurate than midpoint rerooting, but its relative accuracy compared to using outgroups to root gene trees depends on the size of the dataset and levels of deviations from the strict clock. We show high levels of error for all methods of rooting estimated gene trees due to factors that include effects of gene tree discordance, deviations from the clock, and gene tree estimation error. Our simulations, however, did not reveal significant differences between two equivalent methods for species tree estimation that use rooted and unrooted input, namely, STAR and NJst. Nevertheless, our results point to limitations of existing scalable rooting methods.
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Affiliation(s)
- Uyen Mai
- Dept of Computer Science and Engineering, University of California at San Diego, San Diego, CA, United States of America
| | - Erfan Sayyari
- Dept of Electrical and Computer Engineering, University of California at San Diego, San Diego, CA, United States of America
| | - Siavash Mirarab
- Dept of Electrical and Computer Engineering, University of California at San Diego, San Diego, CA, United States of America
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21
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The unconventional kinetoplastid kinetochore: from discovery toward functional understanding. Biochem Soc Trans 2017; 44:1201-1217. [PMID: 27911702 PMCID: PMC5095916 DOI: 10.1042/bst20160112] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 06/15/2016] [Accepted: 06/21/2016] [Indexed: 11/17/2022]
Abstract
The kinetochore is the macromolecular protein complex that drives chromosome segregation in eukaryotes. Its most fundamental function is to connect centromeric DNA to dynamic spindle microtubules. Studies in popular model eukaryotes have shown that centromere protein (CENP)-A is critical for DNA-binding, whereas the Ndc80 complex is essential for microtubule-binding. Given their conservation in diverse eukaryotes, it was widely believed that all eukaryotes would utilize these components to make up a core of the kinetochore. However, a recent study identified an unconventional type of kinetochore in evolutionarily distant kinetoplastid species, showing that chromosome segregation can be achieved using a distinct set of proteins. Here, I review the discovery of the two kinetochore systems and discuss how their studies contribute to a better understanding of the eukaryotic chromosome segregation machinery.
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22
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Phylogenetic rooting using minimal ancestor deviation. Nat Ecol Evol 2017; 1:193. [PMID: 29388565 DOI: 10.1038/s41559-017-0193] [Citation(s) in RCA: 103] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Accepted: 05/16/2017] [Indexed: 01/01/2023]
Abstract
Ancestor-descendent relations play a cardinal role in evolutionary theory. Those relations are determined by rooting phylogenetic trees. Existing rooting methods are hampered by evolutionary rate heterogeneity or the unavailability of auxiliary phylogenetic information. Here we present a rooting approach, the minimal ancestor deviation (MAD) method, which accommodates heterotachy by using all pairwise topological and metric information in unrooted trees. We demonstrate the performance of the method, in comparison to existing rooting methods, by the analysis of phylogenies from eukaryotes and prokaryotes. MAD correctly recovers the known root of eukaryotes and uncovers evidence for the origin of cyanobacteria in the ocean. MAD is more robust and consistent than existing methods, provides measures of the root inference quality and is applicable to any tree with branch lengths.
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23
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Costantini M, Musto H. The Isochores as a Fundamental Level of Genome Structure and Organization: A General Overview. J Mol Evol 2017; 84:93-103. [PMID: 28243687 DOI: 10.1007/s00239-017-9785-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Accepted: 02/15/2017] [Indexed: 11/30/2022]
Abstract
The recent availability of a number of fully sequenced genomes (including marine organisms) allowed to map very precisely the isochores, based on DNA sequences, confirming the results obtained before genome sequencing by the ultracentrifugation in CsCl. In fact, the analytical profile of human DNA showed that the vertebrate genome is a mosaic of isochores, typically megabase-size DNA segments that belong to a small number of families characterized by different GC levels. In this review, we will concentrate on some general genome features regarding the compositional organization from different organisms and their evolution, ranging from vertebrates to invertebrates until unicellular organisms. Since isochores are tightly linked to biological properties such as gene density, replication timing, and recombination, the new level of detail provided by the isochore map helped the understanding of genome structure, function, and evolution. All the findings reported here confirm the idea that the isochores can be considered as a "fundamental level of genome structure and organization." We stress that we do not discuss in this review the origin of isochores, which is still a matter of controversy, but we focus on well established structural and physiological aspects.
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Affiliation(s)
- Maria Costantini
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121, Napoli, Italy.
| | - Héctor Musto
- Laboratorio de Organización y Evolución del Genoma, Unidad de Genómica Evolutiva, Facultad de Ciencias, 11400, Montevideo, Uruguay
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24
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25
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De Oliveira Martins L, Mallo D, Posada D. A Bayesian Supertree Model for Genome-Wide Species Tree Reconstruction. Syst Biol 2016; 65:397-416. [PMID: 25281847 PMCID: PMC4851173 DOI: 10.1093/sysbio/syu082] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Accepted: 09/30/2014] [Indexed: 11/16/2022] Open
Abstract
Current phylogenomic data sets highlight the need for species tree methods able to deal with several sources of gene tree/species tree incongruence. At the same time, we need to make most use of all available data. Most species tree methods deal with single processes of phylogenetic discordance, namely, gene duplication and loss, incomplete lineage sorting (ILS) or horizontal gene transfer. In this manuscript, we address the problem of species tree inference from multilocus, genome-wide data sets regardless of the presence of gene duplication and loss and ILS therefore without the need to identify orthologs or to use a single individual per species. We do this by extending the idea of Maximum Likelihood (ML) supertrees to a hierarchical Bayesian model where several sources of gene tree/species tree disagreement can be accounted for in a modular manner. We implemented this model in a computer program called guenomu whose inputs are posterior distributions of unrooted gene tree topologies for multiple gene families, and whose output is the posterior distribution of rooted species tree topologies. We conducted extensive simulations to evaluate the performance of our approach in comparison with other species tree approaches able to deal with more than one leaf from the same species. Our method ranked best under simulated data sets, in spite of ignoring branch lengths, and performed well on empirical data, as well as being fast enough to analyze relatively large data sets. Our Bayesian supertree method was also very successful in obtaining better estimates of gene trees, by reducing the uncertainty in their distributions. In addition, our results show that under complex simulation scenarios, gene tree parsimony is also a competitive approach once we consider its speed, in contrast to more sophisticated models.
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Affiliation(s)
| | - Diego Mallo
- Department of Biochemistry, Genetics and Immunology, University of Vigo, Vigo, 36310, Spain
| | - David Posada
- Department of Biochemistry, Genetics and Immunology, University of Vigo, Vigo, 36310, Spain
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26
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Impact of gene family evolutionary histories on phylogenetic species tree inference by gene tree parsimony. Mol Phylogenet Evol 2015; 96:9-16. [PMID: 26702957 DOI: 10.1016/j.ympev.2015.12.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Revised: 10/11/2015] [Accepted: 12/03/2015] [Indexed: 11/21/2022]
Abstract
Complicated history of gene duplication and loss brings challenge to molecular phylogenetic inference, especially in deep phylogenies. However, phylogenomic approaches, such as gene tree parsimony (GTP), show advantage over some other approaches in its ability to use gene families with duplications. GTP searches the 'optimal' species tree by minimizing the total cost of biological events such as duplications, but accuracy of GTP and phylogenetic signal in the context of different gene families with distinct histories of duplication and loss are unclear. To evaluate how different evolutionary properties of different gene families can impact on species tree inference, 3900 gene families from seven angiosperms encompassing a wide range of gene content, lineage-specific expansions and contractions were analyzed. It was found that the gene content and total duplication number in a gene family strongly influence species tree inference accuracy, with the highest accuracy achieved at either very low or very high gene content (or duplication number) and lowest accuracy centered in intermediate gene content (or duplication number), as the relationship can fit a binomial regression. Besides, for gene families of similar level of average gene content, those with relatively higher lineage-specific expansion or duplication rates tend to show lower accuracy. Additional correlation tests support that high accuracy for those gene families with large gene content may rely on abundant ancestral copies to provide many subtrees to resolve conflicts, whereas high accuracy for single or low copy gene families are just subject to sequence substitution per se. Very low accuracy reached by gene families of intermediate gene content or duplication number can be due to insufficient subtrees to resolve the conflicts from loss of alternative copies. As these evolutionary properties can significantly influence species tree accuracy, I discussed the potential weighting of the duplication cost by evolutionary properties of gene families in future GTP analyses.
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27
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Hinchliff CE, Smith SA, Allman JF, Burleigh JG, Chaudhary R, Coghill LM, Crandall KA, Deng J, Drew BT, Gazis R, Gude K, Hibbett DS, Katz LA, Laughinghouse HD, McTavish EJ, Midford PE, Owen CL, Ree RH, Rees JA, Soltis DE, Williams T, Cranston KA. Synthesis of phylogeny and taxonomy into a comprehensive tree of life. Proc Natl Acad Sci U S A 2015; 112:12764-9. [PMID: 26385966 PMCID: PMC4611642 DOI: 10.1073/pnas.1423041112] [Citation(s) in RCA: 372] [Impact Index Per Article: 41.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Reconstructing the phylogenetic relationships that unite all lineages (the tree of life) is a grand challenge. The paucity of homologous character data across disparately related lineages currently renders direct phylogenetic inference untenable. To reconstruct a comprehensive tree of life, we therefore synthesized published phylogenies, together with taxonomic classifications for taxa never incorporated into a phylogeny. We present a draft tree containing 2.3 million tips-the Open Tree of Life. Realization of this tree required the assembly of two additional community resources: (i) a comprehensive global reference taxonomy and (ii) a database of published phylogenetic trees mapped to this taxonomy. Our open source framework facilitates community comment and contribution, enabling the tree to be continuously updated when new phylogenetic and taxonomic data become digitally available. Although data coverage and phylogenetic conflict across the Open Tree of Life illuminate gaps in both the underlying data available for phylogenetic reconstruction and the publication of trees as digital objects, the tree provides a compelling starting point for community contribution. This comprehensive tree will fuel fundamental research on the nature of biological diversity, ultimately providing up-to-date phylogenies for downstream applications in comparative biology, ecology, conservation biology, climate change, agriculture, and genomics.
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Affiliation(s)
- Cody E Hinchliff
- Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109
| | - Stephen A Smith
- Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109;
| | | | | | - Ruchi Chaudhary
- Department of Biology, University of Florida, Gainesville, FL 32611
| | | | - Keith A Crandall
- Computational Biology Institute, George Washington University, Ashburn, VA 20147
| | - Jiabin Deng
- Department of Biology, University of Florida, Gainesville, FL 32611
| | - Bryan T Drew
- Department of Biology, University of Nebraska-Kearney, Kearney, NE 68849
| | - Romina Gazis
- Department of Biology, Clark University, Worcester, MA 01610
| | - Karl Gude
- School of Journalism, Michigan State University, East Lansing, MI 48824
| | - David S Hibbett
- Department of Biology, Clark University, Worcester, MA 01610
| | - Laura A Katz
- Biological Science, Clark Science Center, Smith College, Northampton, MA 01063
| | | | - Emily Jane McTavish
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, KS 66045
| | | | | | | | - Jonathan A Rees
- National Evolutionary Synthesis Center, Duke University, Durham, NC 27705
| | - Douglas E Soltis
- Department of Biology, University of Florida, Gainesville, FL 32611; Florida Museum of Natural History, University of Florida, Gainesville, FL 32611
| | - Tiffani Williams
- Computer Science and Engineering, Texas A&M University, College Station, TX 77843
| | - Karen A Cranston
- National Evolutionary Synthesis Center, Duke University, Durham, NC 27705;
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28
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Williams TA, Heaps SE, Cherlin S, Nye TMW, Boys RJ, Embley TM. New substitution models for rooting phylogenetic trees. Philos Trans R Soc Lond B Biol Sci 2015; 370:20140336. [PMID: 26323766 PMCID: PMC4571574 DOI: 10.1098/rstb.2014.0336] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/04/2015] [Indexed: 12/23/2022] Open
Abstract
The root of a phylogenetic tree is fundamental to its biological interpretation, but standard substitution models do not provide any information on its position. Here, we describe two recently developed models that relax the usual assumptions of stationarity and reversibility, thereby facilitating root inference without the need for an outgroup. We compare the performance of these models on a classic test case for phylogenetic methods, before considering two highly topical questions in evolutionary biology: the deep structure of the tree of life and the root of the archaeal radiation. We show that all three alignments contain meaningful rooting information that can be harnessed by these new models, thus complementing and extending previous work based on outgroup rooting. In particular, our analyses exclude the root of the tree of life from the eukaryotes or Archaea, placing it on the bacterial stem or within the Bacteria. They also exclude the root of the archaeal radiation from several major clades, consistent with analyses using other rooting methods. Overall, our results demonstrate the utility of non-reversible and non-stationary models for rooting phylogenetic trees, and identify areas where further progress can be made.
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Affiliation(s)
- Tom A Williams
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Sarah E Heaps
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK School of Mathematics and Statistics, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
| | - Svetlana Cherlin
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK School of Mathematics and Statistics, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
| | - Tom M W Nye
- School of Mathematics and Statistics, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
| | - Richard J Boys
- School of Mathematics and Statistics, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
| | - T Martin Embley
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
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29
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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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30
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Polyphyly of nuclear lamin genes indicates an early eukaryotic origin of the metazoan-type intermediate filament proteins. Sci Rep 2015; 5:10652. [PMID: 26024016 PMCID: PMC4448529 DOI: 10.1038/srep10652] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Accepted: 04/20/2015] [Indexed: 12/24/2022] Open
Abstract
The nuclear lamina is a protein meshwork associated with the inner side of the nuclear envelope contributing structural, signalling and regulatory functions. Here, I report on the evolution of an important component of the lamina, the lamin intermediate filament proteins, across the eukaryotic tree of life. The lamins show a variety of protein domain and sequence motif architectures beyond the classical α-helical rod, nuclear localisation signal, immunoglobulin domain and CaaX motif organisation, suggesting extension and adaptation of functions in many species. I identified lamin genes not only in metazoa and Amoebozoa as previously described, but also in other opisthokonts including Ichthyosporea and choanoflagellates, in oomycetes, a sub-family of Stramenopiles, and in Rhizaria, implying that they must have been present very early in eukaryotic evolution if not even the last common ancestor of all extant eukaryotes. These data considerably extend the current perception of lamin evolution and have important implications with regard to the evolution of the nuclear envelope.
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31
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Inaba K. Calcium sensors of ciliary outer arm dynein: functions and phylogenetic considerations for eukaryotic evolution. Cilia 2015; 4:6. [PMID: 25932323 PMCID: PMC4415241 DOI: 10.1186/s13630-015-0015-z] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2014] [Accepted: 03/23/2015] [Indexed: 12/31/2022] Open
Abstract
The motility of eukaryotic cilia and flagella is modulated in response to several extracellular stimuli. Ca(2+) is the most critical intracellular factor for these changes in motility, directly acting on the axonemes and altering flagellar asymmetry. Calaxin is an opisthokont-specific neuronal calcium sensor protein first described in the sperm of the ascidian Ciona intestinalis. It binds to a heavy chain of two-headed outer arm dynein in a Ca(2+)-dependent manner and regulates 'asymmetric' wave propagation at high concentrations of Ca(2+). A Ca(2+)-binding subunit of outer arm dynein in Chlamydomonas reinhardtii, the light chain 4 (LC4), which is a Ca(2+)-sensor phylogenetically different from calaxin, shows Ca(2+)-dependent binding to a heavy chain of three-headed outer arm dynein. However, LC4 appears to participate in 'symmetric' wave propagation at high concentrations of Ca(2+). LC4-type dynein light chain is present in bikonts, except for some subclasses of the Excavata. Thus, flagellar asymmetry-symmetry conversion in response to Ca(2+) concentration represents a 'mirror image' relationship between Ciona and Chlamydomonas. Phylogenetic analyses indicate the duplication, divergence, and loss of heavy chain and Ca(2+)-sensors of outer arm dynein among excavate species. These features imply a divergence point with respect to Ca(2+)-dependent regulation of outer arm dynein in cilia and flagella during the evolution of eukaryotic supergroups.
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Affiliation(s)
- Kazuo Inaba
- Shimoda Marine Research Center, University of Tsukuba, 5-10-1 Shimoda, Shizuoka, 415-0025 Japan
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32
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Costantini M. An overview on genome organization of marine organisms. Mar Genomics 2015; 24 Pt 1:3-9. [PMID: 25899406 DOI: 10.1016/j.margen.2015.03.015] [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: 02/18/2015] [Revised: 03/17/2015] [Accepted: 03/17/2015] [Indexed: 11/16/2022]
Abstract
In this review we will concentrate on some general genome features of marine organisms and their evolution, ranging from vertebrate to invertebrates until unicellular organisms. Before genome sequencing, the ultracentrifugation in CsCl led to high resolution of mammalian DNA (without seeing at the sequence). The analytical profile of human DNA showed that the vertebrate genome is a mosaic of isochores, typically megabase-size DNA segments that belong in a small number of families characterized by different GC levels. The recent availability of a number of fully sequenced genomes allowed mapping very precisely the isochores, based on DNA sequences. Since isochores are tightly linked to biological properties such as gene density, replication timing and recombination, the new level of detail provided by the isochore map helped the understanding of genome structure, function and evolution. This led the current level of knowledge and to further insights.
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Affiliation(s)
- Maria Costantini
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy.
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33
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Abstract
The large phylogenetic distance separating eukaryotic genes and their archaeal orthologs has prevented identification of the position of the eukaryotic root in phylogenomic studies. Recently, an innovative approach has been proposed to circumvent this issue: the use as phylogenetic markers of proteins that have been transferred from bacterial donor sources to eukaryotes, after their emergence from Archaea. Using this approach, two recent independent studies have built phylogenomic datasets based on bacterial sequences, leading to different predictions of the eukaryotic root. Taking advantage of additional genome sequences from the jakobid Andalucia godoyi and the two known malawimonad species (Malawimonas jakobiformis and Malawimonas californiana), we reanalyzed these two phylogenomic datasets. We show that both datasets pinpoint the same phylogenetic position of the eukaryotic root that is between "Unikonta" and "Bikonta," with malawimonad and collodictyonid lineages on the Unikonta side of the root. Our results firmly indicate that (i) the supergroup Excavata is not monophyletic and (ii) the last common ancestor of eukaryotes was a biflagellate organism. Based on our results, we propose to rename the two major eukaryotic groups Unikonta and Bikonta as Opimoda and Diphoda, respectively.
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34
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Niculescu VF. The stem cell biology of the protist pathogen entamoeba invadens in the context of eukaryotic stem cell evolution. ACTA ACUST UNITED AC 2015. [DOI: 10.7243/2054-717x-2-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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35
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Katz LA, Grant JR. Taxon-Rich Phylogenomic Analyses Resolve the Eukaryotic Tree of Life and Reveal the Power of Subsampling by Sites. Syst Biol 2014; 64:406-15. [DOI: 10.1093/sysbio/syu126] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2014] [Accepted: 12/15/2014] [Indexed: 01/14/2023] Open
Affiliation(s)
- Laura A. Katz
- Department of Biological Sciences, Smith College, Northampton, MA 01063, USA and 2Program in Organismic and Evolutionary Biology, UMass-Amherst, Amherst MA 01003, USA
- Department of Biological Sciences, Smith College, Northampton, MA 01063, USA and 2Program in Organismic and Evolutionary Biology, UMass-Amherst, Amherst MA 01003, USA
| | - Jessica R. Grant
- Department of Biological Sciences, Smith College, Northampton, MA 01063, USA and 2Program in Organismic and Evolutionary Biology, UMass-Amherst, Amherst MA 01003, USA
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36
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Chaudhary R, Boussau B, Burleigh JG, Fernández-Baca D. Assessing approaches for inferring species trees from multi-copy genes. Syst Biol 2014; 64:325-39. [PMID: 25540456 DOI: 10.1093/sysbio/syu128] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
With the availability of genomic sequence data, there is increasing interest in using genes with a possible history of duplication and loss for species tree inference. Here we assess the performance of both nonprobabilistic and probabilistic species tree inference approaches using gene duplication and loss and coalescence simulations. We evaluated the performance of gene tree parsimony (GTP) based on duplication (Only-dup), duplication and loss (Dup-loss), and deep coalescence (Deep-c) costs, the NJst distance method, the MulRF supertree method, and PHYLDOG, which jointly estimates gene trees and species tree using a hierarchical probabilistic model. We examined the effects of gene tree and species sampling, gene tree error, and duplication and loss rates on the accuracy of phylogenetic estimates. In the 10-taxon duplication and loss simulation experiments, MulRF is more accurate than the other methods when the duplication and loss rates are low, and Dup-loss is generally the most accurate when the duplication and loss rates are high. PHYLDOG performs well in 10-taxon duplication and loss simulations, but its run time is prohibitively long on larger data sets. In the larger duplication and loss simulation experiments, MulRF outperforms all other methods in experiments with at most 100 taxa; however, in the larger simulation, Dup-loss generally performs best. In all duplication and loss simulation experiments with more than 10 taxa, all methods perform better with more gene trees and fewer missing sequences, and they are all affected by gene tree error. Our results also highlight high levels of error in estimates of duplications and losses from GTP methods and demonstrate the usefulness of methods based on generic tree distances for large analyses.
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Affiliation(s)
- Ruchi Chaudhary
- Department of Computer Science, Iowa State University, Ames, IA 50011, USA; Department of Biology, University of Florida, Gainesville, FL 32611, USA; and Université de Lyon, Université Lyon 1, CNRS, UMR 5558, Laboratoire de Biométrie et Biologie Evolutive, Villeurbanne F-69622, France Department of Computer Science, Iowa State University, Ames, IA 50011, USA; Department of Biology, University of Florida, Gainesville, FL 32611, USA; and Université de Lyon, Université Lyon 1, CNRS, UMR 5558, Laboratoire de Biométrie et Biologie Evolutive, Villeurbanne F-69622, France
| | - Bastien Boussau
- Department of Computer Science, Iowa State University, Ames, IA 50011, USA; Department of Biology, University of Florida, Gainesville, FL 32611, USA; and Université de Lyon, Université Lyon 1, CNRS, UMR 5558, Laboratoire de Biométrie et Biologie Evolutive, Villeurbanne F-69622, France
| | - J Gordon Burleigh
- Department of Computer Science, Iowa State University, Ames, IA 50011, USA; Department of Biology, University of Florida, Gainesville, FL 32611, USA; and Université de Lyon, Université Lyon 1, CNRS, UMR 5558, Laboratoire de Biométrie et Biologie Evolutive, Villeurbanne F-69622, France
| | - David Fernández-Baca
- Department of Computer Science, Iowa State University, Ames, IA 50011, USA; Department of Biology, University of Florida, Gainesville, FL 32611, USA; and Université de Lyon, Université Lyon 1, CNRS, UMR 5558, Laboratoire de Biométrie et Biologie Evolutive, Villeurbanne F-69622, France
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37
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Abstract
BACKGROUND Evolutionary studies are complicated by discordance between gene trees and the species tree in which they evolved. Dealing with discordant trees often relies on comparison costs between gene and species trees, including the well-established Robinson-Foulds, gene duplication, and deep coalescence costs. While these costs have provided credible results for binary rooted gene trees, corresponding cost definitions for non-binary unrooted gene trees, which are frequently occurring in practice, are challenged by biological realism. RESULT We propose a natural extension of the well-established costs for comparing unrooted and non-binary gene trees with rooted binary species trees using a binary refinement model. For the duplication cost we describe an efficient algorithm that is based on a linear time reduction and also computes an optimal rooted binary refinement of the given gene tree. Finally, we show that similar reductions lead to solutions for computing the deep coalescence and the Robinson-Foulds costs. CONCLUSION Our binary refinement of Robinson-Foulds, gene duplication, and deep coalescence costs for unrooted and non-binary gene trees together with the linear time reductions provided here for computing these costs significantly extends the range of trees that can be incorporated into approaches dealing with discordance.
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Affiliation(s)
- Pawel Górecki
- Institute of Informatics, University of Warsaw, Banacha 2, 02-097 Warsaw, Poland
| | - Oliver Eulenstein
- Department of Computer Science, Iowa State University, Atanasoff Hall 212, 50011 Ames, USA
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38
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Baum DA, Baum B. An inside-out origin for the eukaryotic cell. BMC Biol 2014; 12:76. [PMID: 25350791 PMCID: PMC4210606 DOI: 10.1186/s12915-014-0076-2] [Citation(s) in RCA: 97] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Accepted: 09/17/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Although the origin of the eukaryotic cell has long been recognized as the single most profound change in cellular organization during the evolution of life on earth, this transition remains poorly understood. Models have always assumed that the nucleus and endomembrane system evolved within the cytoplasm of a prokaryotic cell. RESULTS Drawing on diverse aspects of cell biology and phylogenetic data, we invert the traditional interpretation of eukaryotic cell evolution. We propose that an ancestral prokaryotic cell, homologous to the modern-day nucleus, extruded membrane-bound blebs beyond its cell wall. These blebs functioned to facilitate material exchange with ectosymbiotic proto-mitochondria. The cytoplasm was then formed through the expansion of blebs around proto-mitochondria, with continuous spaces between the blebs giving rise to the endoplasmic reticulum, which later evolved into the eukaryotic secretory system. Further bleb-fusion steps yielded a continuous plasma membrane, which served to isolate the endoplasmic reticulum from the environment. CONCLUSIONS The inside-out theory is consistent with diverse kinds of data and provides an alternative framework by which to explore and understand the dynamic organization of modern eukaryotic cells. It also helps to explain a number of previously enigmatic features of cell biology, including the autonomy of nuclei in syncytia and the subcellular localization of protein N-glycosylation, and makes many predictions, including a novel mechanism of interphase nuclear pore insertion.
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39
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Abstract
The root of the eukaryotic tree is a major unresolved question in evolutionary biology. A recent study marshals mitochondrial genes to place that root between the enigmatic Excavates and all other eukaryotes, providing an interesting new perspective on early eukaryotic evolution.
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Affiliation(s)
- Tom A Williams
- Institute for Cell and Molecular Biosciences, University of Newcastle, Newcastle upon Tyne NE2 4HH, UK.
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40
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Abstract
In the tree reconciliation approach for species tree inference, a tree that has the minimum reconciliation score for given gene trees is taken as an estimate of the species tree. The scoring models used in existing tree reconciliation methods include the duplication, mutation, and deep coalescence costs. Since existing inference methods all are heuristic, their performances are often evaluated by using the Robinson-Foulds (RF) distance between the true species trees and the estimates output on simulated multi-locus datasets. To better understand these methods, we study the relationships between the duplication cost and the RF distance. We prove that the gap between the duplication cost and the RF distance is unbounded, but the symmetric duplication cost is logarithmically equivalent to the RF distance. The relationships between other reconciliation costs and the RF distance are also investigated.
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Affiliation(s)
- Yu Zheng
- Department of Mathematics, National University of Singapore, Singapore
| | - Louxin Zhang
- Department of Mathematics, National University of Singapore, Singapore
- Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore
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41
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Eme L, Sharpe SC, Brown MW, Roger AJ. On the age of eukaryotes: evaluating evidence from fossils and molecular clocks. Cold Spring Harb Perspect Biol 2014; 6:6/8/a016139. [PMID: 25085908 DOI: 10.1101/cshperspect.a016139] [Citation(s) in RCA: 116] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Our understanding of the phylogenetic relationships among eukaryotic lineages has improved dramatically over the few past decades thanks to the development of sophisticated phylogenetic methods and models of evolution, in combination with the increasing availability of sequence data for a variety of eukaryotic lineages. Concurrently, efforts have been made to infer the age of major evolutionary events along the tree of eukaryotes using fossil-calibrated molecular clock-based methods. Here, we review the progress and pitfalls in estimating the age of the last eukaryotic common ancestor (LECA) and major lineages. After reviewing previous attempts to date deep eukaryote divergences, we present the results of a Bayesian relaxed-molecular clock analysis of a large dataset (159 proteins, 85 taxa) using 19 fossil calibrations. We show that for major eukaryote groups estimated dates of divergence, as well as their credible intervals, are heavily influenced by the relaxed molecular clock models and methods used, and by the nature and treatment of fossil calibrations. Whereas the estimated age of LECA varied widely, ranging from 1007 (943-1102) Ma to 1898 (1655-2094) Ma, all analyses suggested that the eukaryotic supergroups subsequently diverged rapidly (i.e., within 300 Ma of LECA). The extreme variability of these and previously published analyses preclude definitive conclusions regarding the age of major eukaryote clades at this time. As more reliable fossil data on eukaryotes from the Proterozoic become available and improvements are made in relaxed molecular clock modeling, we may be able to date the age of extant eukaryotes more precisely.
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Affiliation(s)
- Laura Eme
- Centre for Comparative Genomics and Evolutionary Bioinformatics, Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax B3H 4R2, Canada
| | - Susan C Sharpe
- Centre for Comparative Genomics and Evolutionary Bioinformatics, Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax B3H 4R2, Canada
| | - Matthew W Brown
- Centre for Comparative Genomics and Evolutionary Bioinformatics, Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax B3H 4R2, Canada
| | - Andrew J Roger
- Centre for Comparative Genomics and Evolutionary Bioinformatics, Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax B3H 4R2, Canada
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42
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Feeney MJ, Dwyer J, Hasler-Lewis CM, Milner JA, Noakes M, Rowe S, Wach M, Beelman RB, Caldwell J, Cantorna MT, Castlebury LA, Chang ST, Cheskin LJ, Clemens R, Drescher G, Fulgoni VL, Haytowitz DB, Hubbard VS, Law D, Myrdal Miller A, Minor B, Percival SS, Riscuta G, Schneeman B, Thornsbury S, Toner CD, Woteki CE, Wu D. Mushrooms and Health Summit proceedings. J Nutr 2014; 144:1128S-36S. [PMID: 24812070 PMCID: PMC4056650 DOI: 10.3945/jn.114.190728] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The Mushroom Council convened the Mushrooms and Health Summit in Washington, DC, on 9-10 September 2013. The proceedings are synthesized in this article. Although mushrooms have long been regarded as health-promoting foods, research specific to their role in a healthful diet and in health promotion has advanced in the past decade. The earliest mushroom cultivation was documented in China, which remains among the top global mushroom producers, along with the United States, Italy, The Netherlands, and Poland. Although considered a vegetable in dietary advice, mushrooms are fungi, set apart by vitamin B-12 in very low quantity but in the same form found in meat, ergosterol converted with UV light to vitamin D2, and conjugated linoleic acid. Mushrooms are a rare source of ergothioneine as well as selenium, fiber, and several other vitamins and minerals. Some preclinical and clinical studies suggest impacts of mushrooms on cognition, weight management, oral health, and cancer risk. Preliminary evidence suggests that mushrooms may support healthy immune and inflammatory responses through interaction with the gut microbiota, enhancing development of adaptive immunity, and improved immune cell functionality. In addition to imparting direct nutritional and health benefits, analysis of U.S. food intake survey data reveals that mushrooms are associated with higher dietary quality. Also, early sensory research suggests that mushrooms blended with meats and lower sodium dishes are well liked and may help to reduce intakes of red meat and salt without compromising taste. As research progresses on the specific health effects of mushrooms, there is a need for effective communication efforts to leverage mushrooms to improve overall dietary quality.
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Affiliation(s)
- Mary Jo Feeney
- Consultant to the Food and Agriculture Industries, Los Altos, CA
| | - Johanna Dwyer
- Tufts Medical School and USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA
| | - Clare M. Hasler-Lewis
- Robert Mondavi Institute for Wine and Food Science, University of California, Davis, Davis, CA
| | - John A. Milner
- Beltsville Human Nutrition Research Center, Agricultural Research Service, USDA, Beltsville, MD
| | - Manny Noakes
- Commonwealth Scientific and Industrial Research Organization, Adelaide, Australia
| | | | | | - Robert B. Beelman
- Center for Plant and Mushroom Products for Health, Department of Food Science, The Pennsylvania State University, University Park, PA
| | | | - Margherita T. Cantorna
- Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, PA
| | - Lisa A. Castlebury
- Systematic Mycology and Microbiology Laboratory, Agricultural Research Service, USDA, Beltsville, MD
| | - Shu-Ting Chang
- The Chinese University of Hong Kong, McKellar, Australian Capital Territory, Australia
| | - Lawrence J. Cheskin
- Johns Hopkins Weight Management Center and Department of Health, Behavior and Society, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD
| | - Roger Clemens
- International Center for Regulatory Science, School of Pharmacy, University of Southern California, Los Angeles, CA
| | | | | | - David B. Haytowitz
- Nutrient Data Laboratory, Beltsville Human Nutrition Research Center, Agricultural Research Service, USDA, Beltsville, MD
| | - Van S. Hubbard
- NIH Division of Nutrition Research Coordination and the National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Department of Health and Human Services, Bethesda, MD
| | - David Law
- Gourmet Mushrooms, Inc, Sebastopol, CA
| | | | | | - Susan S. Percival
- Food Science and Human Nutrition Department, University of Florida, Gainesville, FL
| | - Gabriela Riscuta
- Nutritional Science Research Group, Division of Cancer Prevention, National Cancer Institute, NIH, Rockville, MD
| | | | - Suzanne Thornsbury
- Market and Trade Economics Division, Economic Research Service, USDA, Washington, DC
| | | | | | - Dayong Wu
- Nutritional Immunology Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging and Friedman School of Nutrition Science and Policy, Tufts University, Boston, MA
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43
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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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44
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Grant JR, Katz LA. Building a phylogenomic pipeline for the eukaryotic tree of life - addressing deep phylogenies with genome-scale data. PLOS CURRENTS 2014; 6. [PMID: 24707447 PMCID: PMC3973741 DOI: 10.1371/currents.tol.c24b6054aebf3602748ac042ccc8f2e9] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Background
Understanding the evolutionary relationships of all eukaryotes on Earth remains a paramount goal of modern biology, yet analyzing homologous sequences across 1.8 billion years of eukaryotic evolution is challenging. Many existing tools for identifying gene orthologs are inadequate when working with heterogeneous rates of evolution and endosymbiotic/lateral gene transfer. Moreover, genomic-scale sequencing, which was once the domain of large sequencing centers, has advanced to the point where small laboratories can now generate the data needed for phylogenomic studies. This has opened the door for increased taxonomic sampling as individual research groups have the ability to conduct genome-scale projects on their favorite non-model organism.
Results
Here we present some of the tools developed, and insights gained, as we created a pipeline that combines data-mining from public databases and our own transcriptome data to study the eukaryotic tree of life. The first steps of a phylogenomic pipeline involve choosing taxa and loci, and making decisions about how to handle alleles, paralogs and non-overlapping sequences. Next, orthologs are aligned for analyses including gene tree reconstruction and concatenation for supermatrix approaches. To build our pipeline, we created scripts written in Python that integrate third-party tools with custom methods. As a test case, we present the placement of five amoebae on the eukaryotic tree of life based on analyses of transcriptome data. Our scripts available on GitHUb and may be used as-is for automated analyses of large scale phylogenomics, or adapted for use in other types of studies.
Conclusion
Analyses on the scale of all eukaryotes present challenges not necessarily found in studies of more closely related organisms. Our approach will be of relevance to others for whom existing third-party tools fail to fully answer desired phylogenetic questions.
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Affiliation(s)
- Jessica R Grant
- Department of Biological Sciences, Smith College, Northampton, Massachusetts, USA
| | - Laura A Katz
- Department of Biological Sciences, Smith College, Northampton, Massachusetts, USA
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Resjö S, Ali A, Meijer HJG, Seidl MF, Snel B, Sandin M, Levander F, Govers F, Andreasson E. Quantitative Label-Free Phosphoproteomics of Six Different Life Stages of the Late Blight Pathogen Phytophthora infestans Reveals Abundant Phosphorylation of Members of the CRN Effector Family. J Proteome Res 2014; 13:1848-59. [DOI: 10.1021/pr4009095] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Svante Resjö
- Department
of Plant Protection Biology, Swedish University of Agricultural Sciences, SE-230 53 Alnarp, Sweden
| | - Ashfaq Ali
- Department
of Plant Protection Biology, Swedish University of Agricultural Sciences, SE-230 53 Alnarp, Sweden
| | - Harold J. G. Meijer
- Laboratory
of Phytopathology, Wageningen University, 6700 EE Wageningen, The Netherlands
| | - Michael F. Seidl
- Laboratory
of Phytopathology, Wageningen University, 6700 EE Wageningen, The Netherlands
- Theoretical
Biology and Bioinformatics, Department of Biology, Utrecht University, 3508
TC Utrecht, The Netherlands
- Centre
for BioSystems
Genomics, 6700 AB Wageningen, The Netherlands
| | - Berend Snel
- Theoretical
Biology and Bioinformatics, Department of Biology, Utrecht University, 3508
TC Utrecht, The Netherlands
- Centre
for BioSystems
Genomics, 6700 AB Wageningen, The Netherlands
| | - Marianne Sandin
- Department
of Immunotechnology, Lund University, S-223 81 Lund, Sweden
| | - Fredrik Levander
- Department
of Immunotechnology, Lund University, S-223 81 Lund, Sweden
| | - Francine Govers
- Laboratory
of Phytopathology, Wageningen University, 6700 EE Wageningen, The Netherlands
- Centre
for BioSystems
Genomics, 6700 AB Wageningen, The Netherlands
| | - Erik Andreasson
- Department
of Plant Protection Biology, Swedish University of Agricultural Sciences, SE-230 53 Alnarp, Sweden
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Akiyoshi B, Gull K. Discovery of unconventional kinetochores in kinetoplastids. Cell 2014; 156:1247-1258. [PMID: 24582333 PMCID: PMC3978658 DOI: 10.1016/j.cell.2014.01.049] [Citation(s) in RCA: 171] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Revised: 01/06/2014] [Accepted: 01/10/2014] [Indexed: 11/17/2022]
Abstract
The kinetochore is the macromolecular protein complex that directs chromosome segregation in eukaryotes. It has been widely assumed that the core kinetochore consists of proteins that are common to all eukaryotes. However, no conventional kinetochore components have been identified in any kinetoplastid genome, thus challenging this assumption of universality. Here, we report the identification of 19 kinetochore proteins (KKT1–19) in Trypanosoma brucei. The majority is conserved among kinetoplastids, but none of them has detectable homology to conventional kinetochore proteins. These proteins instead have a variety of features not found in conventional kinetochore proteins. We propose that kinetoplastids build kinetochores using a distinct set of proteins. These findings provide important insights into the longstanding problem of the position of the root of the eukaryotic tree of life. Conventional kinetochore proteins cannot be identified in any kinetoplastid genome 19 kinetochore proteins were identified in Trypanosoma brucei Kinetoplastids possess unconventional kinetochores This discovery supports the hypothesis that kinetoplastids branched very early
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Affiliation(s)
- Bungo Akiyoshi
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK; Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK.
| | - Keith Gull
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
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An alternative root for the eukaryote tree of life. Curr Biol 2014; 24:465-70. [PMID: 24508168 DOI: 10.1016/j.cub.2014.01.036] [Citation(s) in RCA: 153] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Revised: 12/12/2013] [Accepted: 01/16/2014] [Indexed: 01/02/2023]
Abstract
The root of the eukaryote tree of life defines some of the most fundamental relationships among species. It is also critical for defining the last eukaryote common ancestor (LECA), the shared heritage of all extant species. The unikont-bikont root has been the reigning paradigm for eukaryotes for more than 10 years but is becoming increasingly controversial. We developed a carefully vetted data set, consisting of 37 nuclear-encoded proteins of close bacterial ancestry (euBacs) and their closest bacterial relatives, augmented by deep sequencing of the Acrasis kona (Heterolobosea, Discoba) transcriptome. Phylogenetic analysis of these data produces a highly robust, fully resolved global phylogeny of eukaryotes. The tree sorts all examined eukaryotes into three megagroups and identifies the Discoba, and potentially its parent taxon Excavata, as the sister group to the bulk of known eukaryote diversity, the proposed Neozoa (Amorphea + Stramenopila+Alveolata+Rhizaria+Plantae [SARP]). All major alternative hypotheses are rejected with as little as ∼50% of the data, and this resolution is unaffected by the presence of fast-evolving alignment positions or distant outgroup sequences. This "neozoan-excavate" root revises hypotheses of early eukaryote evolution and highlights the importance of the poorly studied Discoba for understanding the evolution of eukaryotic diversity and basic cellular processes.
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Costantini M, Alvarez-Valin F, Costantini S, Cammarano R, Bernardi G. Compositional patterns in the genomes of unicellular eukaryotes. BMC Genomics 2013; 14:755. [PMID: 24188247 PMCID: PMC4007698 DOI: 10.1186/1471-2164-14-755] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Accepted: 10/31/2013] [Indexed: 11/29/2022] Open
Abstract
Background The genomes of multicellular eukaryotes are compartmentalized in mosaics of isochores, large and fairly homogeneous stretches of DNA that belong to a small number of families characterized by different average GC levels, by different gene concentration (that increase with GC), different chromatin structures, different replication timing in the cell cycle, and other different properties. A question raised by these basic results concerns how far back in evolution the compartmentalized organization of the eukaryotic genomes arose. Results In the present work we approached this problem by studying the compositional organization of the genomes from the unicellular eukaryotes for which full sequences are available, the sample used being representative. The average GC levels of the genomes from unicellular eukaryotes cover an extremely wide range (19%-60% GC) and the compositional patterns of individual genomes are extremely different but all genomes tested show a compositional compartmentalization. Conclusions The average GC range of the genomes of unicellular eukaryotes is very broad (as broad as that of prokaryotes) and individual compositional patterns cover a very broad range from very narrow to very complex. Both features are not surprising for organisms that are very far from each other both in terms of phylogenetic distances and of environmental life conditions. Most importantly, all genomes tested, a representative sample of all supergroups of unicellular eukaryotes, are compositionally compartmentalized, a major difference with prokaryotes.
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Affiliation(s)
- Maria Costantini
- Laboratory of Animal Physiology and Evolution, Stazione Zoologica Anton Dohrn, Villa Comunale, Naples 80121, Italy.
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The Microtubular Cytoskeleton of the Apusomonad Thecamonas, a Sister Lineage to the Opisthokonts. Protist 2013; 164:598-621. [DOI: 10.1016/j.protis.2013.05.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Revised: 04/30/2013] [Accepted: 05/31/2013] [Indexed: 01/16/2023]
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50
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Fulnecková J, Sevcíková T, Fajkus J, Lukesová A, Lukes M, Vlcek C, Lang BF, Kim E, Eliás M, Sykorová E. A broad phylogenetic survey unveils the diversity and evolution of telomeres in eukaryotes. Genome Biol Evol 2013; 5:468-83. [PMID: 23395982 PMCID: PMC3622300 DOI: 10.1093/gbe/evt019] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Telomeres, ubiquitous and essential structures of eukaryotic chromosomes, are known to come in a variety of forms, but knowledge about their actual diversity and evolution across the whole phylogenetic breadth of the eukaryotic life remains fragmentary. To fill this gap, we employed a complex experimental approach to probe telomeric minisatellites in various phylogenetically diverse groups of algae. Our most remarkable results include the following findings: 1) algae of the streptophyte class Klebsormidiophyceae possess the Chlamydomonas-type telomeric repeat (TTTTAGGG) or, in at least one species, a novel TTTTAGG repeat, indicating an evolutionary transition from the Arabidopsis-type repeat (TTTAGGG) ancestral for Chloroplastida; 2) the Arabidopsis-type repeat is also present in telomeres of Xanthophyceae, in contrast to the presence of the human-type repeat (TTAGGG) in other ochrophytes studied, and of the photosynthetic alveolate Chromera velia, consistent with its phylogenetic position close to apicomplexans and dinoflagellates; 3) glaucophytes and haptophytes exhibit the human-type repeat in their telomeres; and 4) ulvophytes and rhodophytes have unusual telomere structures recalcitrant to standard analysis. To obtain additional details on the distribution of different telomere types in eukaryotes, we performed in silico analyses of genomic data from major eukaryotic lineages, utilizing also genome assemblies from our on-going genome projects for representatives of three hitherto unsampled lineages (jakobids, malawimonads, and goniomonads). These analyses confirm the human-type repeat as the most common and possibly ancestral in eukaryotes, but alternative motifs replaced it along the phylogeny of diverse eukaryotic lineages, some of them several times independently.
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Affiliation(s)
- Jana Fulnecková
- Institute of Biophysics, Academy of Sciences of the Czech Republic, Brno, Czech Republic
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