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Benites LF, Bucchini F, Sanchez-Brosseau S, Grimsley N, Vandepoele K, Piganeau G. Evolutionary Genomics of Sex-Related Chromosomes at the Base of the Green Lineage. Genome Biol Evol 2021; 13:6380139. [PMID: 34599324 PMCID: PMC8557840 DOI: 10.1093/gbe/evab216] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/11/2021] [Indexed: 12/11/2022] Open
Abstract
Although sex is now accepted as a ubiquitous and ancestral feature of eukaryotes, direct observation of sex is still lacking in most unicellular eukaryotic lineages. Evidence of sex is frequently indirect and inferred from the identification of genes involved in meiosis from whole genome data and/or the detection of recombination signatures from genetic diversity in natural populations. In haploid unicellular eukaryotes, sex-related chromosomes are named mating-type (MTs) chromosomes and generally carry large genomic regions where recombination is suppressed. These regions have been characterized in Fungi and Chlorophyta and determine gamete compatibility and fusion. Two candidate MT+ and MT− alleles, spanning 450–650 kb, have recently been described in Ostreococcus tauri, a marine phytoplanktonic alga from the Mamiellophyceae class, an early diverging branch in the green lineage. Here, we investigate the architecture and evolution of these candidate MT+ and MT− alleles. We analyzed the phylogenetic profile and GC content of MT gene families in eight different genomes whose divergence has been previously estimated at up to 640 Myr, and found evidence that the divergence of the two MT alleles predates speciation in the Ostreococcus genus. Phylogenetic profiles of MT trans-specific polymorphisms in gametologs disclosed candidate MTs in two additional species, and possibly a third. These Mamiellales MT candidates are likely to be the oldest mating-type loci described to date, which makes them fascinating models to investigate the evolutionary mechanisms of haploid sex determination in eukaryotes.
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Affiliation(s)
- Luis Felipe Benites
- Integrative Biology of Marine Organisms (BIOM), Sorbonne University, CNRS, Oceanological Observatory of Banyuls, Banyuls-sur-Mer, France
| | - François Bucchini
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Belgium.,VIB Center for Plant Systems Biology, Ghent, Belgium
| | - Sophie Sanchez-Brosseau
- Integrative Biology of Marine Organisms (BIOM), Sorbonne University, CNRS, Oceanological Observatory of Banyuls, Banyuls-sur-Mer, France
| | - Nigel Grimsley
- Integrative Biology of Marine Organisms (BIOM), Sorbonne University, CNRS, Oceanological Observatory of Banyuls, Banyuls-sur-Mer, France
| | - Klaas Vandepoele
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Belgium.,VIB Center for Plant Systems Biology, Ghent, Belgium.,Bioinformatics Institute Ghent, Ghent University, Belgium
| | - Gwenaël Piganeau
- Integrative Biology of Marine Organisms (BIOM), Sorbonne University, CNRS, Oceanological Observatory of Banyuls, Banyuls-sur-Mer, France
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Cellular pathways during spawning induction in the starlet sea anemone Nematostella vectensis. Sci Rep 2021; 11:15451. [PMID: 34326433 PMCID: PMC8322078 DOI: 10.1038/s41598-021-95033-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 07/13/2021] [Indexed: 12/12/2022] Open
Abstract
In cnidarians, long-term ecological success relies on sexual reproduction. The sea anemone Nematostella vectensis, which has emerged as an important model organism for developmental studies, can be induced for spawning by temperature elevation and light exposure. To uncover molecular mechanisms and pathways underlying spawning, we characterized the transcriptome of Nematostella females before and during spawning induction. We identified an array of processes involving numerous receptors, circadian clock components, cytoskeleton, and extracellular transcripts that are upregulated upon spawning induction. Concurrently, processes related to the cell cycle, fatty acid metabolism, and other housekeeping functions are downregulated. Real-time qPCR revealed that light exposure has a minor effect on expression levels of most examined transcripts, implying that temperature change is a stronger inducer for spawning in Nematostella. Our findings reveal the potential mechanisms that may enable the mesenteries to serve as a gonad-like tissue for the developing oocytes and expand our understanding of sexual reproduction in cnidarians.
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Picard MAL, Vicoso B, Bertrand S, Escriva H. Diversity of Modes of Reproduction and Sex Determination Systems in Invertebrates, and the Putative Contribution of Genetic Conflict. Genes (Basel) 2021; 12:1136. [PMID: 34440310 PMCID: PMC8391622 DOI: 10.3390/genes12081136] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 07/08/2021] [Accepted: 07/11/2021] [Indexed: 12/30/2022] Open
Abstract
About eight million animal species are estimated to live on Earth, and all except those belonging to one subphylum are invertebrates. Invertebrates are incredibly diverse in their morphologies, life histories, and in the range of the ecological niches that they occupy. A great variety of modes of reproduction and sex determination systems is also observed among them, and their mosaic-distribution across the phylogeny shows that transitions between them occur frequently and rapidly. Genetic conflict in its various forms is a long-standing theory to explain what drives those evolutionary transitions. Here, we review (1) the different modes of reproduction among invertebrate species, highlighting sexual reproduction as the probable ancestral state; (2) the paradoxical diversity of sex determination systems; (3) the different types of genetic conflicts that could drive the evolution of such different systems.
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Affiliation(s)
- Marion Anne Lise Picard
- Sorbonne Université, CNRS, Biologie Intégrative des Organismes Marins (BIOM), Observatoire Océanologique, 66650 Banyuls-sur-Mer, France; (S.B.); (H.E.)
| | - Beatriz Vicoso
- Institute of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria;
| | - Stéphanie Bertrand
- Sorbonne Université, CNRS, Biologie Intégrative des Organismes Marins (BIOM), Observatoire Océanologique, 66650 Banyuls-sur-Mer, France; (S.B.); (H.E.)
| | - Hector Escriva
- Sorbonne Université, CNRS, Biologie Intégrative des Organismes Marins (BIOM), Observatoire Océanologique, 66650 Banyuls-sur-Mer, France; (S.B.); (H.E.)
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Ramšak B, Markau J, Pazen T, Dahlmann TA, Krappmann S, Kück U. The master regulator MAT1-1-1 of fungal mating binds to its targets via a conserved motif in the human pathogen Aspergillus fumigatus. G3-GENES GENOMES GENETICS 2021; 11:6026963. [PMID: 33598704 PMCID: PMC8022922 DOI: 10.1093/g3journal/jkaa012] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 10/23/2020] [Indexed: 12/18/2022]
Abstract
Mating-type transcription factors are master regulators of sexually related signal transduction pathways in fungi; however, their recognition of specific DNA sequences from target genes is widely undetermined. Here, we identified and characterized the DNA-binding sequence of the MAT1-1-1 alpha-box domain transcription factor from the human pathogen Aspergillus fumigatus. In order to explore MAT1-1-1 DNA-binding targets, we used the previously reported MAT1-1-1 binding motif from Penicillium chrysogenum, in a bioinformatics approach. We identified 18 A. fumigatus genes carrying the MAT1.1 sequence in their upstream region, among them genes for the α-pheromone precursor (PpgA), G-protein-coupled pheromone receptor (PreA), and for TomA, an unidentified protein. To validate our prediction further, quantification of transcript levels showed a decrease in expression of ppgA, tomA, and others in a MAT1-1 deletion strain. For a functional analysis of the binding sites, truncated variants of the A. fumigatus MAT1-1-1 gene were introduced into Escherichia coli for heterologous expression. The yield of recombinant protein was further optimized for the AfMAT1-1-178-235 variant that harbors an extended alpha-box domain. AfMAT1-1-178-235 bound to a subset of the most strongly upregulated genes: ppgA, preA, and tomA. The DNA-binding specificity was confirmed by testing mutated binding sequences, as well as performing competition experiments with specific and non-specific sequences. Finally, equilibrium dissociation constants of 1.83 ± 0.1 and 1.45 ± 0.26 µM were determined for AfMAT1-1-178-235 and fusion protein GST-AfMAT1-1-178-235. Collectively, these findings provide further insights into AfMAT1-1-1-mediated gene expression and imply that alpha-box domain regulators from other members of Eurotiales control fungal development in a conserved manner.
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Affiliation(s)
- Barbara Ramšak
- Allgemeine und Molekulare Botanik, Ruhr-Universität Bochum, 44780 Bochum, Germany
| | - Jessica Markau
- Allgemeine und Molekulare Botanik, Ruhr-Universität Bochum, 44780 Bochum, Germany
| | - Tobias Pazen
- Mikrobiologisches Institut - Klinische Mikrobiologie, Immunologie und Hygiene, Universitätsklinikum Erlangen und Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Tim A Dahlmann
- Allgemeine und Molekulare Botanik, Ruhr-Universität Bochum, 44780 Bochum, Germany
| | - Sven Krappmann
- Mikrobiologisches Institut - Klinische Mikrobiologie, Immunologie und Hygiene, Universitätsklinikum Erlangen und Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Ulrich Kück
- Allgemeine und Molekulare Botanik, Ruhr-Universität Bochum, 44780 Bochum, Germany
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Skejo J, Garg SG, Gould SB, Hendriksen M, Tria FDK, Bremer N, Franjević D, Blackstone NW, Martin WF. Evidence for a Syncytial Origin of Eukaryotes from Ancestral State Reconstruction. Genome Biol Evol 2021; 13:evab096. [PMID: 33963405 PMCID: PMC8290118 DOI: 10.1093/gbe/evab096] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/28/2021] [Indexed: 12/11/2022] Open
Abstract
Modern accounts of eukaryogenesis entail an endosymbiotic encounter between an archaeal host and a proteobacterial endosymbiont, with subsequent evolution giving rise to a unicell possessing a single nucleus and mitochondria. The mononucleate state of the last eukaryotic common ancestor (LECA) is seldom, if ever, questioned, even though cells harboring multiple (syncytia, coenocytes, and polykaryons) are surprisingly common across eukaryotic supergroups. Here, we present a survey of multinucleated forms. Ancestral character state reconstruction for representatives of 106 eukaryotic taxa using 16 different possible roots and supergroup sister relationships, indicate that LECA, in addition to being mitochondriate, sexual, and meiotic, was multinucleate. LECA exhibited closed mitosis, which is the rule for modern syncytial forms, shedding light on the mechanics of its chromosome segregation. A simple mathematical model shows that within LECA's multinucleate cytosol, relationships among mitochondria and nuclei were neither one-to-one, nor one-to-many, but many-to-many, placing mitonuclear interactions and cytonuclear compatibility at the evolutionary base of eukaryotic cell origin. Within a syncytium, individual nuclei and individual mitochondria function as the initial lower-level evolutionary units of selection, as opposed to individual cells, during eukaryogenesis. Nuclei within a syncytium rescue each other's lethal mutations, thereby postponing selection for viable nuclei and cytonuclear compatibility to the generation of spores, buffering transitional bottlenecks at eukaryogenesis. The prokaryote-to-eukaryote transition is traditionally thought to have left no intermediates, yet if eukaryogenesis proceeded via a syncytial common ancestor, intermediate forms have persisted to the present throughout the eukaryotic tree as syncytia but have so far gone unrecognized.
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Affiliation(s)
- Josip Skejo
- Institute for Molecular Evolution, Heinrich-Heine University Düsseldorf, Düsseldorf, Germany
- Faculty of Science, Division of Zoology, Department of Biology, University of Zagreb, Evolution Lab, Zagreb, Croatia
| | - Sriram G Garg
- Institute for Molecular Evolution, Heinrich-Heine University Düsseldorf, Düsseldorf, Germany
| | - Sven B Gould
- Institute for Molecular Evolution, Heinrich-Heine University Düsseldorf, Düsseldorf, Germany
| | - Michael Hendriksen
- Institute for Molecular Evolution, Heinrich-Heine University Düsseldorf, Düsseldorf, Germany
| | - Fernando D K Tria
- Institute for Molecular Evolution, Heinrich-Heine University Düsseldorf, Düsseldorf, Germany
| | - Nico Bremer
- Institute for Molecular Evolution, Heinrich-Heine University Düsseldorf, Düsseldorf, Germany
| | - Damjan Franjević
- Faculty of Science, Division of Zoology, Department of Biology, University of Zagreb, Evolution Lab, Zagreb, Croatia
| | - Neil W Blackstone
- Department of Biological Sciences, Northern Illinois University, DeKalb, IL, USA
| | - William F Martin
- Institute for Molecular Evolution, Heinrich-Heine University Düsseldorf, Düsseldorf, Germany
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56
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Peixoto JF, dos Santos DG, Ribeiro L, de Oliveira VSC, Nunes-da-Fonseca R, Nepomuceno-Silva JL. Establishment of suitable reference genes for studying relative gene expression during the transition from trophozoites to cyst-like stages and first evidences of stress-induced expression of meiotic genes in Trichomonas vaginalis. Parasitology 2021; 148:934-946. [PMID: 33827719 PMCID: PMC11010144 DOI: 10.1017/s0031182021000585] [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: 11/01/2020] [Revised: 03/26/2021] [Accepted: 03/29/2021] [Indexed: 11/07/2022]
Abstract
Trichomonas vaginalis is a parasite of the human urogenital tract and the causative agent of trichomoniasis, a sexually transmitted disease of worldwide importance. This parasite is usually found as a motile flagellated trophozoite. However, when subjected to stressful microenvironmental conditions, T. vaginalis trophozoites can differentiate into peculiar cyst-like stages, which exhibit notable physiological resistance to unfavourable conditions. Although well documented in morphological and proteomic terms, patterns of gene expression changes involved in the cellular differentiation into cyst-like stages are mostly unknown. The real-time reverse transcription polymerase chain reaction (RT-qPCR) is recognized as a sensitive and accurate method for quantification of gene expression, providing fluorescence-based data that are proportional to the amount of a target RNA. However, the reliability of relative expression studies depends on the validation of suitable reference genes, which RNAs exhibit a minimum of variation between tested conditions. Here, we attempt to determine suitable reference genes to be used as controls of invariant expression during cold-induced in vitro differentiation of T. vaginalis trophozoites into cyst-like forms. Furthermore, we reveal that the mRNA from the meiotic recombinase Dmc1 is upregulated during this process, indicating that cryptic sexual events may take place in cyst-like stages of T. vaginalis.
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Affiliation(s)
- Juliana Figueiredo Peixoto
- Laboratório Integrado de Bioquímica Hatisaburo Masuda (LIBHM), Instituto de Biodiversidade e Sustentabilidade (NUPEM/UFRJ), Universidade Federal do Rio de Janeiro, Macaé/RJ, Brazil
| | - Daniele Graças dos Santos
- Laboratório Integrado de Bioquímica Hatisaburo Masuda (LIBHM), Instituto de Biodiversidade e Sustentabilidade (NUPEM/UFRJ), Universidade Federal do Rio de Janeiro, Macaé/RJ, Brazil
| | - Lupis Ribeiro
- Laboratório Integrado de Ciências Morfofuncionais (LICM), Instituto de Biodiversidade e Sustentabilidade (NUPEM/UFRJ), Universidade Federal do Rio de Janeiro, Macaé/RJ, Brazil
| | - Vitor Silva Cândido de Oliveira
- Laboratório Integrado de Bioquímica Hatisaburo Masuda (LIBHM), Instituto de Biodiversidade e Sustentabilidade (NUPEM/UFRJ), Universidade Federal do Rio de Janeiro, Macaé/RJ, Brazil
| | - Rodrigo Nunes-da-Fonseca
- Laboratório Integrado de Ciências Morfofuncionais (LICM), Instituto de Biodiversidade e Sustentabilidade (NUPEM/UFRJ), Universidade Federal do Rio de Janeiro, Macaé/RJ, Brazil
| | - José Luciano Nepomuceno-Silva
- Laboratório Integrado de Bioquímica Hatisaburo Masuda (LIBHM), Instituto de Biodiversidade e Sustentabilidade (NUPEM/UFRJ), Universidade Federal do Rio de Janeiro, Macaé/RJ, Brazil
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Boekhout T, Aime MC, Begerow D, Gabaldón T, Heitman J, Kemler M, Khayhan K, Lachance MA, Louis EJ, Sun S, Vu D, Yurkov A. The evolving species concepts used for yeasts: from phenotypes and genomes to speciation networks. FUNGAL DIVERS 2021; 109:27-55. [PMID: 34720775 PMCID: PMC8550739 DOI: 10.1007/s13225-021-00475-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 05/31/2021] [Indexed: 12/12/2022]
Abstract
Here we review how evolving species concepts have been applied to understand yeast diversity. Initially, a phenotypic species concept was utilized taking into consideration morphological aspects of colonies and cells, and growth profiles. Later the biological species concept was added, which applied data from mating experiments. Biophysical measurements of DNA similarity between isolates were an early measure that became more broadly applied with the advent of sequencing technology, leading to a sequence-based species concept using comparisons of parts of the ribosomal DNA. At present phylogenetic species concepts that employ sequence data of rDNA and other genes are universally applied in fungal taxonomy, including yeasts, because various studies revealed a relatively good correlation between the biological species concept and sequence divergence. The application of genome information is becoming increasingly common, and we strongly recommend the use of complete, rather than draft genomes to improve our understanding of species and their genome and genetic dynamics. Complete genomes allow in-depth comparisons on the evolvability of genomes and, consequently, of the species to which they belong. Hybridization seems a relatively common phenomenon and has been observed in all major fungal lineages that contain yeasts. Note that hybrids may greatly differ in their post-hybridization development. Future in-depth studies, initially using some model species or complexes may shift the traditional species concept as isolated clusters of genetically compatible isolates to a cohesive speciation network in which such clusters are interconnected by genetic processes, such as hybridization.
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Affiliation(s)
- Teun Boekhout
- Westerdijk Fungal Biodiversity Institute, Utrecht, The Netherlands
- Institute of Biodiversity and Ecosystem Dynamics (IBED), University of Amsterdam, Amsterdam, The Netherlands
| | - M. Catherine Aime
- Dept Botany and Plant Pathology, College of Agriculture, Purdue University, West Lafayette, IN 47907 USA
| | - Dominik Begerow
- Evolution of Plants and Fungi, Ruhr-University Bochum, 44801 Bochum, Germany
| | - Toni Gabaldón
- Barcelona Supercomputing Centre (BSC–CNS), Jordi Girona, 29, 08034 Barcelona, Spain
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac, 10, 08028 Barcelona, Spain
- Catalan Institution for Research and Advanced Studies (ICREA), Barcelona, Spain
| | - Joseph Heitman
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710 USA
| | - Martin Kemler
- Evolution of Plants and Fungi, Ruhr-University Bochum, 44801 Bochum, Germany
| | - Kantarawee Khayhan
- Department of Microbiology and Parasitology, Faculty of Medical Sciences, University of Phayao, Phayao, 56000 Thailand
| | - Marc-André Lachance
- Department of Biology, University of Western Ontario, London, ON N6A 5B7 Canada
| | - Edward J. Louis
- Department of Genetics and Genome Biology, Genetic Architecture of Complex Traits, University of Leicester, Leicester, LE1 7RH UK
| | - Sheng Sun
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710 USA
| | - Duong Vu
- Westerdijk Fungal Biodiversity Institute, Utrecht, The Netherlands
| | - Andrey Yurkov
- German Collection of Microorganisms and Cell Cultures, Leibniz Institute DSMZ, Brunswick, Germany
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58
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Auboeuf D. The Physics-Biology continuum challenges darwinism: Evolution is directed by the homeostasis-dependent bidirectional relation between genome and phenotype. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2021; 167:121-139. [PMID: 34097984 DOI: 10.1016/j.pbiomolbio.2021.05.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 05/19/2021] [Accepted: 05/31/2021] [Indexed: 10/21/2022]
Abstract
The physics-biology continuum relies on the fact that life emerged from prebiotic molecules. Here, I argue that life emerged from the coupling between nucleic acid and protein synthesis during which proteins (or proto-phenotypes) maintained the physicochemical parameter equilibria (or proto-homeostasis) in the proximity of their encoding nucleic acids (or proto-genomes). This protected the proto-genome physicochemical integrity (i.e., atomic composition) from environmental physicochemical constraints, and therefore increased the probability of reproducing the proto-genome without variation. From there, genomes evolved depending on the biological activities they generated in response to environmental fluctuations. Thus, a genome maintaining homeostasis (i.e., internal physicochemical parameter equilibria), despite and in response to environmental fluctuations, maintains its physicochemical integrity and has therefore a higher probability to be reproduced without variation. Consequently, descendants have a higher probability to share the same phenotype than their parents. Otherwise, the genome is modified during replication as a consequence of the imbalance of the internal physicochemical parameters it generates, until new mutation-deriving biological activities maintain homeostasis in offspring. In summary, evolution depends on feedforward and feedback loops between genome and phenotype, as the internal physicochemical conditions that a genome generates ─ through its derived phenotype in response to environmental fluctuations ─ in turn either guarantee its stability or direct its variation. Evolution may not be explained by the Darwinism-derived, unidirectional principle (random mutations-phenotypes-natural selection) but rather by the bidirectional relationship between genome and phenotype, in which the phenotype in interaction with the environment directs the evolution of the genome it derives from.
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Affiliation(s)
- Didier Auboeuf
- ENS de Lyon, Univ Claude Bernard, CNRS UMR 5239, INSERM U1210, Laboratory of Biology and Modelling of the Cell, 46 Allée D'Italie, Site Jacques Monod, F-69007, Lyon, France.
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Anders A, Colin R, Banderas A, Sourjik V. Asymmetric mating behavior of isogamous budding yeast. SCIENCE ADVANCES 2021; 7:7/24/eabf8404. [PMID: 34117059 PMCID: PMC8195471 DOI: 10.1126/sciadv.abf8404] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 04/28/2021] [Indexed: 05/12/2023]
Abstract
Anisogamy, the size difference between small male and large female gametes, is known to enable selection for sexual dimorphism and behavioral differences between sexes. Nevertheless, even isogamous species exhibit molecular asymmetries between mating types, which are known to ensure their self-incompatibility. Here, we show that different properties of the pheromones secreted by the MATa and MATα mating types of budding yeast lead to asymmetry in their behavioral responses during mating in mixed haploid populations, which resemble behavioral asymmetries between gametes in anisogamous organisms. MATa behaves as a random searcher that is stimulated in proportion to the fraction of MATα partner cells within the population, whereas MATα behaves as a short-range directional distance sensor. Mathematical modeling suggests that the observed asymmetric responses can enhance efficiency of mating and might thus provide a selective advantage. Our results demonstrate that the emergence of asymmetric mating behavior did not require anisogamy-based sexual selection.
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Affiliation(s)
- Alexander Anders
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
- LOEWE Research Center for Synthetic Microbiology (SYNMIKRO), Marburg, Germany
| | - Remy Colin
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
- LOEWE Research Center for Synthetic Microbiology (SYNMIKRO), Marburg, Germany
| | - Alvaro Banderas
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany.
- Laboratoire Physico Chimie Curie, CNRS UMR168, Institut Curie, Paris, France
| | - Victor Sourjik
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany.
- LOEWE Research Center for Synthetic Microbiology (SYNMIKRO), Marburg, Germany
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60
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Reproduction in Trypanosomatids: Past and Present. BIOLOGY 2021; 10:biology10060471. [PMID: 34071741 PMCID: PMC8230138 DOI: 10.3390/biology10060471] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 05/20/2021] [Accepted: 05/25/2021] [Indexed: 01/07/2023]
Abstract
Simple Summary The reproduction of trypanosomatids is a fundamental issue for host–parasite interaction, and its biological importance lies in knowing how these species acquire new defense mechanisms against the countermeasures imposed by the host, which is consistent with the theory of the endless race or the Red Queen hypothesis for the existence of meiotic sex. Moreover, the way these species re-produce may also be at the origin of novel and more virulent clades and is relevant from a thera-peutic or vaccination point of view, as sex may contribute to increased tolerance and even to the rapid acquisition of drug resistance mechanisms. Kinetoplastids are single-celled organisms, many of them being responsible for important parasitic diseases, globally termed neglected diseases, which are endemic in low-income countries. Leishmaniasis, African (sleeping sickness) and American trypanosomiasis (Chagas disease) caused by trypanosomatids are among the most ne-glected tropical scourges related to poverty and poor health systems. The reproduction of these microorganisms has long been considered to be clonal due to population genetic observations. However, there is increasing evidence of true sex and genetic exchange events under laboratory conditions. We would like to highlight the importance of this topic in the field of host/parasite in-terplay, virulence, and drug resistance. Abstract Diseases caused by trypanosomatids (Sleeping sickness, Chagas disease, and leishmaniasis) are a serious public health concern in low-income endemic countries. These diseases are produced by single-celled parasites with a diploid genome (although aneuploidy is frequent) organized in pairs of non-condensable chromosomes. To explain the way they reproduce through the analysis of natural populations, the theory of strict clonal propagation of these microorganisms was taken as a rule at the beginning of the studies, since it partially justified their genomic stability. However, numerous experimental works provide evidence of sexual reproduction, thus explaining certain naturally occurring events that link the number of meiosis per mitosis and the frequency of mating. Recent techniques have demonstrated genetic exchange between individuals of the same species under laboratory conditions, as well as the expression of meiosis specific genes. The current debate focuses on the frequency of genomic recombination events and its impact on the natural parasite population structure. This paper reviews the results and techniques used to demonstrate the existence of sex in trypanosomatids, the inheritance of kinetoplast DNA (maxi- and minicircles), the impact of genetic exchange in these parasites, and how it can contribute to the phenotypic diversity of natural populations.
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Peacock L, Kay C, Farren C, Bailey M, Carrington M, Gibson W. Sequential production of gametes during meiosis in trypanosomes. Commun Biol 2021; 4:555. [PMID: 33976359 PMCID: PMC8113336 DOI: 10.1038/s42003-021-02058-5] [Citation(s) in RCA: 15] [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] [Received: 05/12/2020] [Accepted: 03/24/2021] [Indexed: 02/03/2023] Open
Abstract
Meiosis is a core feature of eukaryotes that occurs in all major groups, including the early diverging excavates. In this group, meiosis and production of haploid gametes have been described in the pathogenic protist, Trypanosoma brucei, and mating occurs in the salivary glands of the insect vector, the tsetse fly. Here, we searched for intermediate meiotic stages among trypanosomes from tsetse salivary glands. Many different cell types were recovered, including trypanosomes in Meiosis I and gametes. Significantly, we found trypanosomes containing three nuclei with a 1:2:1 ratio of DNA contents. Some of these cells were undergoing cytokinesis, yielding a mononucleate gamete and a binucleate cell with a nuclear DNA content ratio of 1:2. This cell subsequently produced three more gametes in two further rounds of division. Expression of the cell fusion protein HAP2 (GCS1) was not confined to gametes, but also extended to meiotic intermediates. We propose a model whereby the two nuclei resulting from Meiosis I undergo asynchronous Meiosis II divisions with sequential production of haploid gametes.
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Affiliation(s)
- Lori Peacock
- School of Biological Sciences University of Bristol, Bristol, UK
- Bristol Veterinary School, University of Bristol, Bristol, UK
| | - Chris Kay
- School of Biological Sciences University of Bristol, Bristol, UK
| | - Chloe Farren
- School of Biological Sciences University of Bristol, Bristol, UK
| | - Mick Bailey
- Bristol Veterinary School, University of Bristol, Bristol, UK
| | - Mark Carrington
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Wendy Gibson
- School of Biological Sciences University of Bristol, Bristol, UK.
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62
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Tria FDK, Brueckner J, Skejo J, Xavier JC, Kapust N, Knopp M, Wimmer JLE, Nagies FSP, Zimorski V, Gould SB, Garg SG, Martin WF. Gene Duplications Trace Mitochondria to the Onset of Eukaryote Complexity. Genome Biol Evol 2021; 13:evab055. [PMID: 33739376 PMCID: PMC8175051 DOI: 10.1093/gbe/evab055] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/14/2021] [Indexed: 12/15/2022] Open
Abstract
The last eukaryote common ancestor (LECA) possessed mitochondria and all key traits that make eukaryotic cells more complex than their prokaryotic ancestors, yet the timing of mitochondrial acquisition and the role of mitochondria in the origin of eukaryote complexity remain debated. Here, we report evidence from gene duplications in LECA indicating an early origin of mitochondria. Among 163,545 duplications in 24,571 gene trees spanning 150 sequenced eukaryotic genomes, we identify 713 gene duplication events that occurred in LECA. LECA's bacterial-derived genes include numerous mitochondrial functions and were duplicated significantly more often than archaeal-derived and eukaryote-specific genes. The surplus of bacterial-derived duplications in LECA most likely reflects the serial copying of genes from the mitochondrial endosymbiont to the archaeal host's chromosomes. Clustering, phylogenies and likelihood ratio tests for 22.4 million genes from 5,655 prokaryotic and 150 eukaryotic genomes reveal no evidence for lineage-specific gene acquisitions in eukaryotes, except from the plastid in the plant lineage. That finding, and the functions of bacterial genes duplicated in LECA, suggests that the bacterial genes in eukaryotes are acquisitions from the mitochondrion, followed by vertical gene evolution and differential loss across eukaryotic lineages, flanked by concomitant lateral gene transfer among prokaryotes. Overall, the data indicate that recurrent gene transfer via the copying of genes from a resident mitochondrial endosymbiont to archaeal host chromosomes preceded the onset of eukaryotic cellular complexity, favoring mitochondria-early over mitochondria-late hypotheses for eukaryote origin.
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Affiliation(s)
- Fernando D K Tria
- Institute for Molecular Evolution, Heinrich Heine University Düsseldorf, Germany
| | - Julia Brueckner
- Institute for Molecular Evolution, Heinrich Heine University Düsseldorf, Germany
| | - Josip Skejo
- Institute for Molecular Evolution, Heinrich Heine University Düsseldorf, Germany
- Faculty of Science, University of Zagreb, Croatia
| | - Joana C Xavier
- Institute for Molecular Evolution, Heinrich Heine University Düsseldorf, Germany
| | - Nils Kapust
- Institute for Molecular Evolution, Heinrich Heine University Düsseldorf, Germany
| | - Michael Knopp
- Institute for Molecular Evolution, Heinrich Heine University Düsseldorf, Germany
| | - Jessica L E Wimmer
- Institute for Molecular Evolution, Heinrich Heine University Düsseldorf, Germany
| | - Falk S P Nagies
- Institute for Molecular Evolution, Heinrich Heine University Düsseldorf, Germany
| | - Verena Zimorski
- Institute for Molecular Evolution, Heinrich Heine University Düsseldorf, Germany
| | - Sven B Gould
- Institute for Molecular Evolution, Heinrich Heine University Düsseldorf, Germany
| | - Sriram G Garg
- Institute for Molecular Evolution, Heinrich Heine University Düsseldorf, Germany
| | - William F Martin
- Institute for Molecular Evolution, Heinrich Heine University Düsseldorf, Germany
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63
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Paganini J, Pontarotti P. Search for MHC/TCR-Like Systems in Living Organisms. Front Immunol 2021; 12:635521. [PMID: 34017326 PMCID: PMC8129030 DOI: 10.3389/fimmu.2021.635521] [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: 11/30/2020] [Accepted: 04/07/2021] [Indexed: 12/02/2022] Open
Abstract
Highly polymorphic loci evolved many times over the history of species. These polymorphic loci are involved in three types of functions: kind recognition, self-incompatibility, and the jawed vertebrate adaptive immune system (AIS). In the first part of this perspective, we reanalyzed and described some cases of polymorphic loci reported in the literature. There is a convergent evolution within each functional category and between functional categories, suggesting that the emergence of these self/non-self recognition loci has occurred multiple times throughout the evolutionary history. Most of the highly polymorphic loci are coding for proteins that have a homophilic interaction or heterophilic interaction between linked loci, leading to self or non-self-recognition. The highly polymorphic MHCs, which are involved in the AIS have a different functional mechanism, as they interact through presented self or non-self-peptides with T cell receptors, whose diversity is generated by somatic recombination. Here we propose a mechanism called “the capacity of recognition competition mechanism” that might contribute to the evolution of MHC polymorphism. We propose that the published cases corresponding to these three biological categories represent a small part of what can be found throughout the tree of life, and that similar mechanisms will be found many times, including the one where polymorphic loci interact with somatically generated loci.
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Affiliation(s)
| | - Pierre Pontarotti
- XEGEN, Gemenos, France.,Aix Marseille Université, IRD, APHM, MEPHI, IHU Méditerranée Infection, Marseille, France.,SNC5039 CNRS, Marseille, France
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64
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A functional bacteria-derived restriction modification system in the mitochondrion of a heterotrophic protist. PLoS Biol 2021; 19:e3001126. [PMID: 33891594 PMCID: PMC8099122 DOI: 10.1371/journal.pbio.3001126] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 05/05/2021] [Accepted: 03/23/2021] [Indexed: 01/04/2023] Open
Abstract
The overarching trend in mitochondrial genome evolution is functional streamlining coupled with gene loss. Therefore, gene acquisition by mitochondria is considered to be exceedingly rare. Selfish elements in the form of self-splicing introns occur in many organellar genomes, but the wider diversity of selfish elements, and how they persist in the DNA of organelles, has not been explored. In the mitochondrial genome of a marine heterotrophic katablepharid protist, we identify a functional type II restriction modification (RM) system originating from a horizontal gene transfer (HGT) event involving bacteria related to flavobacteria. This RM system consists of an HpaII-like endonuclease and a cognate cytosine methyltransferase (CM). We demonstrate that these proteins are functional by heterologous expression in both bacterial and eukaryotic cells. These results suggest that a mitochondrion-encoded RM system can function as a toxin-antitoxin selfish element, and that such elements could be co-opted by eukaryotic genomes to drive biased organellar inheritance.
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65
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Gibson W. The sexual side of parasitic protists. Mol Biochem Parasitol 2021; 243:111371. [PMID: 33872659 DOI: 10.1016/j.molbiopara.2021.111371] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 03/26/2021] [Accepted: 04/13/2021] [Indexed: 01/09/2023]
Abstract
Much of the vast evolutionary landscape occupied by Eukaryotes is dominated by protists. Though parasitism has arisen in many lineages, there are three main groups of parasitic protists of relevance to human and livestock health: the Apicomplexa, including the malaria parasite Plasmodium and coccidian pathogens of livestock such as Eimeria; the excavate flagellates, encompassing a diverse range of protist pathogens including trypanosomes, Leishmania, Giardia and Trichomonas; and the Amoebozoa, including pathogenic amoebae such as Entamoeba. These three groups represent separate, deep branches of the eukaryote tree, underlining their divergent evolutionary histories. Here, I explore what is known about sex in these three main groups of parasitic protists.
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Affiliation(s)
- Wendy Gibson
- School of Biological Sciences, Life Sciences Building, University of Bristol, Bristol, BS8 1TQ, United Kingdom.
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66
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Brandeis M. Were eukaryotes made by sex?: Sex might have been vital for merging endosymbiont and host genomes giving rise to eukaryotes. Bioessays 2021; 43:e2000256. [PMID: 33860546 DOI: 10.1002/bies.202000256] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Revised: 03/16/2021] [Accepted: 03/17/2021] [Indexed: 11/10/2022]
Abstract
I hypothesize that the appearance of sex facilitated the merging of the endosymbiont and host genomes during early eukaryote evolution. Eukaryotes were formed by symbiosis between a bacterium that entered an archaeon, eventually giving rise to mitochondria. This entry was followed by the gradual transfer of most bacterial endosymbiont genes into the archaeal host genome. I argue that the merging of the mitochondrial genes into the host genome was vital for the evolution of genuine eukaryotes. At the time this process commenced it was unprecedented and required a novel mechanism. I suggest that this mechanism was meiotic sex, and that its appearance might have been THE crucial step that enabled the evolution of proper eukaryotes from early endosymbiont containing proto-eukaryotes. Sex might continue to be essential today for keeping genome insertions in check. Also see the video abstract here: https://youtu.be/aVMvWMpomac.
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Affiliation(s)
- Michael Brandeis
- The Department of Genetics, The Hebrew University of Jerusalem, Jerusalem, Israel
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67
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Radzvilavicius A. Beyond the "selfish mitochondrion" theory of uniparental inheritance: A unified theory based on mutational variance redistribution. Bioessays 2021; 43:e2100009. [PMID: 33729620 DOI: 10.1002/bies.202100009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 02/15/2021] [Accepted: 02/16/2021] [Indexed: 11/08/2022]
Abstract
"Selfish" gene theories have offered invaluable insight into eukaryotic genome evolution, but they can also be misleading. The "selfish mitochondrion" hypothesis, developed in the 90s explained uniparental organelle inheritance as a mechanism of conflict resolution, improving cooperation between genetically distinct compartments of the cell. But modern population genetic models provided a more general explanation for uniparental inheritance based on mutational variance redistribution, modulating the efficiency of both purifying and adaptive selection. Nevertheless, as reviewed here, "selfish" conflict theories still dominate the literature. While these hypotheses are rich in metaphor and highly intuitive, selective focus on only one type of mitochondrial mutation limits the generality of our understanding and hinders progress in mito-nuclear evolution theory. Recognizing that uniparental inheritance may have evolved-and is maintained across the eukaryotic tree of life-because of its influence on mutational variance and improved selection will only increase the generality of our evolutionary reasoning, retaining "selfish" conflict explanations as a special case of a much broader theory.
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Affiliation(s)
- Arunas Radzvilavicius
- Department of Philosophy and Charles Perkins Centre, University of Sydney, New South Wales, Australia
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68
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Abstract
All living cells interact dynamically with a constantly changing world. Eukaryotes, in particular, evolved radically new ways to sense and react to their environment. These advances enabled new and more complex forms of cellular behaviour in eukaryotes, including directional movement, active feeding, mating, and responses to predation. But what are the key events and innovations during eukaryogenesis that made all of this possible? Here we describe the ancestral repertoire of eukaryotic excitability and discuss five major cellular innovations that enabled its evolutionary origin. The innovations include a vastly expanded repertoire of ion channels, the emergence of cilia and pseudopodia, endomembranes as intracellular capacitors, a flexible plasma membrane and the relocation of chemiosmotic ATP synthesis to mitochondria, which liberated the plasma membrane for more complex electrical signalling involved in sensing and reacting. We conjecture that together with an increase in cell size, these new forms of excitability greatly amplified the degrees of freedom associated with cellular responses, allowing eukaryotes to vastly outperform prokaryotes in terms of both speed and accuracy. This comprehensive new perspective on the evolution of excitability enriches our view of eukaryogenesis and emphasizes behaviour and sensing as major contributors to the success of eukaryotes. This article is part of the theme issue 'Basal cognition: conceptual tools and the view from the single cell'.
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Affiliation(s)
- Kirsty Y. Wan
- Living Systems Institute, University of Exeter, Stocker Road, Exeter EX4 4QD, UK
| | - Gáspár Jékely
- Living Systems Institute, University of Exeter, Stocker Road, Exeter EX4 4QD, UK
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69
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Russo MT, Ruggiero MV, Manfellotto F, Scriven V, Campbell L, Montresor M, Ferrante MI. New alleles in the mating type determination region of West Atlantic strains of Pseudo-nitzschia multistriata. HARMFUL ALGAE 2021; 103:101995. [PMID: 33980435 DOI: 10.1016/j.hal.2021.101995] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 01/15/2021] [Accepted: 01/25/2021] [Indexed: 06/12/2023]
Abstract
The cosmopolitan, species-rich diatom genus Pseudo-nitzschia represents a good system for the study of speciation, evolution and diversity. Understanding elements linked to population dynamics and life cycle regulation for these species is of particular importance in view of their ability to produce the toxin domoic acid and cause harmful blooms. Pseudo-nitzschia multistriata, one of the toxic species that represents a model for the study of life cycle related questions, is the only diatom for which a sex determination mechanism has been described. Populations in the Gulf of Naples (Mediterranean Sea), can share four different allelic variants (A, M, B, N) of the mating type determination region, and one of them (A) is responsible for the determination of the mating type + (MT+), defined by the MT+ restricted expression of the gene MRP3. Here, we analysed the sex determination genomic region in three new strains isolated from the Gulf of Mexico and compared it to the alleles previously described in the Mediterranean strains. We first show that these geographically distant strains of P. multistriata belong to different populations but can interbreed. Next, we show that the two populations share an overall similar structure of the genomic locus although differences can be seen in the polymorphic regions upstream of MRP3. In strain P4-C1, we amplified and sequenced an allele (M) identical to one of those previously characterized in the Mediterranean strains. In the other two strains, P4-C2 and P4-C5, we identified three new alleles, which we named A2, B2 and N2. P4-C2 and P4-C5 are heterozygous and share the common allele A2 linked to the monoallelic expression of the MT+ specific sex determining gene MRP3. Our results expand information on the global distribution of P. multistriata and on the level of conservation of the sex determination region in different populations. The definition of the extent of intra- and inter-specific conservation of this region would be a relevant addition to our understanding of Pseudo-nitzschia diversity and evolution.
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Affiliation(s)
| | | | | | - Victoria Scriven
- Department of Oceanography, Texas A&M University, 3146 TAMU, College Station, TX 77843, USA
| | - Lisa Campbell
- Department of Oceanography, Texas A&M University, 3146 TAMU, College Station, TX 77843, USA
| | - Marina Montresor
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy.
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70
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Krueger-Hadfield SA, Flanagan BA, Godfroy O, Hill-Spanik KM, Nice CC, Murren CJ, Strand AE, Sotka EE. Using RAD-seq to develop sex-linked markers in a haplodiplontic alga. JOURNAL OF PHYCOLOGY 2021; 57:279-294. [PMID: 33098662 DOI: 10.1111/jpy.13088] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 10/05/2020] [Indexed: 06/11/2023]
Abstract
For many taxa, including isomorphic haplodiplontic macroalgae, determining sex and ploidy is challenging, thereby limiting the scope of some population demographic and genetic studies. Here, we used double-digest restriction site-associated DNA sequencing (ddRAD-seq) to identify sex-linked molecular markers in the widespread red alga Agarophyton vermiculophyllum. In the ddRAD-seq library, we included 10 female gametophytes, 10 male gametophytes, and 16 tetrasporophytes from one native and one non-native site (N = 40 gametophytes and N = 32 tetrasporophytes total). We identified seven putatively female-linked and 19 putatively male-linked sequences. Four female- and eight male-linked markers amplified in all three life cycle stages. Using one female- and one male-linked marker that were sex-specific, we developed a duplex PCR and tested the efficacy of this assay on a subset of thalli sampled at two sites in the non-native range. We confirmed ploidy based on the visual observation of reproductive structures and previous microsatellite genotyping at 10 polymorphic loci. For 32 vegetative thalli, we were able to assign sex and confirm ploidy in these previously genotyped thalli. These markers will be integral to ongoing studies of A. vermiculophyllum invasion. We discuss the utility of RAD-seq over other approaches previously used, such as RAPDs (random amplified polymorphic DNA), for future work designing sex-linked markers in other haplodiplontic macroalgae for which genomes are lacking.
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Affiliation(s)
- Stacy A Krueger-Hadfield
- Department of Biology, University of Alabama at Birmingham, 1300 University Blvd, Birmingham, Alabama, 35294, USA
| | - Ben A Flanagan
- Department of Biological Sciences, University of Southern California, Los Angeles, California, 90089, USA
| | - Olivier Godfroy
- Sorbonne Université, CNRS, Integrative Biology of Marine Models (LBI2M), Station Biologique de Roscoff (SBR), 29680, Roscoff, France
| | - Kristina M Hill-Spanik
- Department of Biology and Grice Marine Lab, College of Charleston, 205 Fort Johnson Road, Charleston, South Carolina, 29412, USA
| | - Chris C Nice
- Department of Biology, Population and Conservation Biology Program, Texas State University, San Marcos, Texas, 78666, USA
| | - Courtney J Murren
- Department of Biology, College of Charleston, 66 George Street, Charleston, South Carolina, 29424, USA
| | - Allan E Strand
- Department of Biology and Grice Marine Lab, College of Charleston, 205 Fort Johnson Road, Charleston, South Carolina, 29412, USA
| | - Erik E Sotka
- Department of Biology and Grice Marine Lab, College of Charleston, 205 Fort Johnson Road, Charleston, South Carolina, 29412, USA
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71
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Kaczmarska I, Ehrman JM. Enlarge or die! An auxospore perspective on diatom diversification. ORG DIVERS EVOL 2021. [DOI: 10.1007/s13127-020-00476-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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72
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Hofstatter PG, Thangavel G, Castellani M, Marques A. Meiosis Progression and Recombination in Holocentric Plants: What Is Known? FRONTIERS IN PLANT SCIENCE 2021; 12:658296. [PMID: 33968114 PMCID: PMC8100227 DOI: 10.3389/fpls.2021.658296] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 03/22/2021] [Indexed: 05/02/2023]
Abstract
Differently from the common monocentric organization of eukaryotic chromosomes, the so-called holocentric chromosomes present many centromeric regions along their length. This chromosomal organization can be found in animal and plant lineages, whose distribution suggests that it has evolved independently several times. Holocentric chromosomes present an advantage: even broken chromosome parts can be correctly segregated upon cell division. However, the evolution of holocentricity brought about consequences to nuclear processes and several adaptations are necessary to cope with this new organization. Centromeres of monocentric chromosomes are involved in a two-step cohesion release during meiosis. To deal with that holocentric lineages developed different adaptations, like the chromosome remodeling strategy in Caenorhabditis elegans or the inverted meiosis in plants. Furthermore, the frequency of recombination at or around centromeres is normally very low and the presence of centromeric regions throughout the entire length of the chromosomes could potentially pose a problem for recombination in holocentric organisms. However, meiotic recombination happens, with exceptions, in those lineages in spite of their holocentric organization suggesting that the role of centromere as recombination suppressor might be altered in these lineages. Most of the available information about adaptations to meiosis in holocentric organisms is derived from the animal model C. elegans. As holocentricity evolved independently in different lineages, adaptations observed in C. elegans probably do not apply to other lineages and very limited research is available for holocentric plants. Currently, we still lack a holocentric model for plants, but good candidates may be found among Cyperaceae, a large angiosperm family. Besides holocentricity, chiasmatic and achiasmatic inverted meiosis are found in the family. Here, we introduce the main concepts of meiotic constraints and adaptations with special focus in meiosis progression and recombination in holocentric plants. Finally, we present the main challenges and perspectives for future research in the field of chromosome biology and meiosis in holocentric plants.
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73
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Sex continuum in the brain and body during adolescence and psychological traits. Nat Hum Behav 2020; 5:265-272. [PMID: 33139896 DOI: 10.1038/s41562-020-00968-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Accepted: 09/17/2020] [Indexed: 01/11/2023]
Abstract
Many traits of the brain and body show marked sex differences, but the distributions of their values overlap substantially between the two sexes. To investigate variations associated with biological sex, beyond binary differences, we create continuous sex scores capturing the inter-individual variability in phenotypes. In an adolescent cohort (n = 1,029; 533 females), we have generated three sex scores based on brain-body traits: 'overall' (48 traits), 'pubertal' (26 traits) and 'non-pubertal' (22 traits). We then conducted sex-stratified multiple linear regressions (adjusting for age) using sex scores to test associations with sex hormones, personality traits and internalizing-externalizing behaviour. Higher sex scores (that is, greater 'femaleness') were associated with lower testosterone in males only, as well as lower extraversion, higher internalizing and lower externalizing in both sexes. The associations with testosterone, internalizing and externalizing were driven by pubertal sex scores, underscoring the importance of adolescence in shaping within-sex individual variability.
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74
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Aubier TG, Galipaud M, Erten EY, Kokko H. Transmissible cancers and the evolution of sex under the Red Queen hypothesis. PLoS Biol 2020; 18:e3000916. [PMID: 33211684 PMCID: PMC7676742 DOI: 10.1371/journal.pbio.3000916] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 09/21/2020] [Indexed: 12/14/2022] Open
Abstract
The predominance of sexual reproduction in eukaryotes remains paradoxical in evolutionary theory. Of the hypotheses proposed to resolve this paradox, the 'Red Queen hypothesis' emphasises the potential of antagonistic interactions to cause fluctuating selection, which favours the evolution and maintenance of sex. Whereas empirical and theoretical developments have focused on host-parasite interactions, the premises of the Red Queen theory apply equally well to any type of antagonistic interactions. Recently, it has been suggested that early multicellular organisms with basic anticancer defences were presumably plagued by antagonistic interactions with transmissible cancers and that this could have played a pivotal role in the evolution of sex. Here, we dissect this argument using a population genetic model. One fundamental aspect distinguishing transmissible cancers from other parasites is the continual production of cancerous cell lines from hosts' own tissues. We show that this influx dampens fluctuating selection and therefore makes the evolution of sex more difficult than in standard Red Queen models. Although coevolutionary cycling can remain sufficient to select for sex under some parameter regions of our model, we show that the size of those regions shrinks once we account for epidemiological constraints. Altogether, our results suggest that horizontal transmission of cancerous cells is unlikely to cause fluctuating selection favouring sexual reproduction. Nonetheless, we confirm that vertical transmission of cancerous cells can promote the evolution of sex through a separate mechanism, known as similarity selection, that does not depend on coevolutionary fluctuations.
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Affiliation(s)
- Thomas G. Aubier
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
| | - Matthias Galipaud
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
| | - E. Yagmur Erten
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
| | - Hanna Kokko
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
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75
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Nishikawa SI, Yamaguchi Y, Suzuki C, Yabe A, Sato Y, Kurihara D, Sato Y, Susaki D, Higashiyama T, Maruyama D. Arabidopsis GEX1 Is a Nuclear Membrane Protein of Gametes Required for Nuclear Fusion During Reproduction. FRONTIERS IN PLANT SCIENCE 2020; 11:548032. [PMID: 33154760 PMCID: PMC7586128 DOI: 10.3389/fpls.2020.548032] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 09/15/2020] [Indexed: 05/25/2023]
Abstract
During the life cycle of flowering plants, nuclear fusion, or karyogamy, occurs three times: once during female gametogenesis, when the two polar nuclei fuse in the central cell, and twice during double fertilization. In Arabidopsis thaliana, nuclear fusion events during sexual reproduction proceed without the breakdown of the nuclear envelope, indicating that nuclear membrane fusion is essential for the completion of this process. Arabidopsis gamete expressed 1 (GEX1) is a membrane protein that is conserved among plant species. GEX1 shares homology with the yeast karyogamy protein Kar5, which is primarily expressed in the nuclear membrane. The GEX1 family represents a putative karyogamy factor. Herein, we show that GEX1 is required for the nuclear fusion events in Arabidopsis reproduction. GEX1-deficient mature female gametophytes were found to contain two unfused polar nuclei in close proximity within the central cell. Electron microscopy showed that the outer membrane of the polar nuclei was connected via the endoplasmic reticulum, whereas the inner membrane remained unfused. These results indicate that GEX1 is involved in polar nuclear membrane fusion following the fusion of the outer nuclear membrane. Furthermore, sperm nuclear fusion events were defective in the fertilized egg and central cell following plasmogamy in the fertilization of gex1-1 female gametophytes by gex1-1 pollen. An analysis of GEX1 localization in the female gametophyte using a transgenic line expressing GFP-tagged GEX1 driven by the GEX1 promoter showed that GEX1 is a nuclear membrane protein in the egg and central cell. Time-lapse live-cell imaging showed that in developing female gametophytes, the nuclear GFP-GEX1 signal was first detectable in the central cell shortly before the polar nuclei came in close contact, and then in the egg cell. Thus, we suggest that the GEX1-family proteins are nuclear membrane proteins involved in karyogamy in the reproduction of eukaryotes including flowering plants.
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Affiliation(s)
| | - Yuki Yamaguchi
- Graduate School of Science and Technology, Niigata University, Niigata, Japan
| | - Chiharu Suzuki
- Graduate School of Science and Technology, Niigata University, Niigata, Japan
| | - Ayaka Yabe
- Graduate School of Science and Technology, Niigata University, Niigata, Japan
| | - Yuzuru Sato
- Biology Program, Faculty of Science, Niigata University, Niigata, Japan
| | - Daisuke Kurihara
- Japan Science and Technology Agency, PRESTO, Nagoya, Japan
- Institute of Transformative Bio-Molecules, Nagoya University, Nagoya, Japan
| | - Yoshikatsu Sato
- Institute of Transformative Bio-Molecules, Nagoya University, Nagoya, Japan
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Japan
| | - Daichi Susaki
- Kihara Institute for Biological Research, Yokohama City University, Yokohama, Japan
| | - Tetsuya Higashiyama
- Institute of Transformative Bio-Molecules, Nagoya University, Nagoya, Japan
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Japan
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Tokyo, Japan
| | - Daisuke Maruyama
- Kihara Institute for Biological Research, Yokohama City University, Yokohama, Japan
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76
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Colnaghi M, Lane N, Pomiankowski A. Genome expansion in early eukaryotes drove the transition from lateral gene transfer to meiotic sex. eLife 2020; 9:58873. [PMID: 32990598 PMCID: PMC7524546 DOI: 10.7554/elife.58873] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 09/03/2020] [Indexed: 12/17/2022] Open
Abstract
Prokaryotes acquire genes from the environment via lateral gene transfer (LGT). Recombination of environmental DNA can prevent the accumulation of deleterious mutations, but LGT was abandoned by the first eukaryotes in favour of sexual reproduction. Here we develop a theoretical model of a haploid population undergoing LGT which includes two new parameters, genome size and recombination length, neglected by previous theoretical models. The greater complexity of eukaryotes is linked with larger genomes and we demonstrate that the benefit of LGT declines rapidly with genome size. The degeneration of larger genomes can only be resisted by increases in recombination length, to the same order as genome size - as occurs in meiosis. Our results can explain the strong selective pressure towards the evolution of sexual cell fusion and reciprocal recombination during early eukaryotic evolution - the origin of meiotic sex.
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Affiliation(s)
- Marco Colnaghi
- CoMPLEX, University College London, London, United Kingdom.,Department of Genetics, Evolution and Environment University College London, London, United Kingdom
| | - Nick Lane
- CoMPLEX, University College London, London, United Kingdom.,Department of Genetics, Evolution and Environment University College London, London, United Kingdom
| | - Andrew Pomiankowski
- CoMPLEX, University College London, London, United Kingdom.,Department of Genetics, Evolution and Environment University College London, London, United Kingdom
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77
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Altenburger A, Blossom HE, Garcia-Cuetos L, Jakobsen HH, Carstensen J, Lundholm N, Hansen PJ, Moestrup Ø, Haraguchi L. Dimorphism in cryptophytes-The case of Teleaulax amphioxeia/ Plagioselmis prolonga and its ecological implications. SCIENCE ADVANCES 2020; 6:6/37/eabb1611. [PMID: 32917704 PMCID: PMC7486100 DOI: 10.1126/sciadv.abb1611] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 07/29/2020] [Indexed: 05/03/2023]
Abstract
Growing evidence suggests that sexual reproduction might be common in unicellular organisms, but observations are sparse. Limited knowledge of sexual reproduction constrains understanding of protist ecology. Although Teleaulax amphioxeia and Plagioselmis prolonga are common marine cryptophytes worldwide, and are also important plastid donors for some kleptoplastic ciliates and dinoflagellates, the ecology and development of these protists are poorly known. We demonstrate that P. prolonga is the haploid form of the diploid T. amphioxeia and describe the seasonal dynamics of these two life stages. The diploid T. amphioxeia dominates during periods of high dissolved inorganic nitrogen (DIN) and low irradiance, temperature, and grazing (winter and early spring), whereas the haploid P. prolonga becomes more abundant during the summer, when DIN is low and irradiance, temperature, and grazing are high. Dimorphic sexual life cycles might explain the success of this species by fostering high genetic diversity and enabling endurance in adverse conditions.
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Affiliation(s)
- A Altenburger
- The Arctic University Museum of Norway, UiT-The Arctic University of Norway, 9006 Tromsø, Norway.
| | - H E Blossom
- Aquatic Ecology Unit, Department of Biology, Lund University, Sölvegatan 37, 22362 Lund, Sweden
| | - L Garcia-Cuetos
- Natural History Museum of Denmark, University of Copenhagen, Gothersgade 130, 1123 Copenhagen, Denmark
| | - H H Jakobsen
- Department of Bioscience, Aarhus University, Frederiksborgvej 399, 4000 Roskilde, Denmark
| | - J Carstensen
- Department of Bioscience, Aarhus University, Frederiksborgvej 399, 4000 Roskilde, Denmark
| | - N Lundholm
- Natural History Museum of Denmark, University of Copenhagen, Gothersgade 130, 1123 Copenhagen, Denmark
| | - P J Hansen
- Marine Biological Section, University of Copenhagen, Strandpromenaden 5, 3000 Helsingør, Denmark
| | - Ø Moestrup
- Marine Biological Section, University of Copenhagen, Universitetsparken 4, 2100 Copenhagen Ø, Denmark
| | - L Haraguchi
- Department of Bioscience, Aarhus University, Frederiksborgvej 399, 4000 Roskilde, Denmark.
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78
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Karakaidos P, Rampias T. Mitonuclear Interactions in the Maintenance of Mitochondrial Integrity. Life (Basel) 2020; 10:life10090173. [PMID: 32878185 PMCID: PMC7555762 DOI: 10.3390/life10090173] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 08/28/2020] [Indexed: 12/27/2022] Open
Abstract
In eukaryotic cells, mitochondria originated in an α-proteobacterial endosymbiont. Although these organelles harbor their own genome, the large majority of genes, originally encoded in the endosymbiont, were either lost or transferred to the nucleus. As a consequence, mitochondria have become semi-autonomous and most of their processes require the import of nuclear-encoded components to be functional. Therefore, the mitochondrial-specific translation has evolved to be coordinated by mitonuclear interactions to respond to the energetic demands of the cell, acquiring unique and mosaic features. However, mitochondrial-DNA-encoded genes are essential for the assembly of the respiratory chain complexes. Impaired mitochondrial function due to oxidative damage and mutations has been associated with numerous human pathologies, the aging process, and cancer. In this review, we highlight the unique features of mitochondrial protein synthesis and provide a comprehensive insight into the mitonuclear crosstalk and its co-evolution, as well as the vulnerabilities of the animal mitochondrial genome.
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79
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Hörandl E, Hadacek F. Oxygen, life forms, and the evolution of sexes in multicellular eukaryotes. Heredity (Edinb) 2020; 125:1-14. [PMID: 32415185 PMCID: PMC7413252 DOI: 10.1038/s41437-020-0317-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 04/26/2020] [Accepted: 04/26/2020] [Indexed: 12/27/2022] Open
Abstract
The evolutionary advantage of different sexual systems in multicellular eukaryotes is still not well understood, because the differentiation into male and female individuals halves offspring production compared with asexuality. Here we propose that various physiological adaptations to oxidative stress could have forged sessility versus motility, and consequently the evolution of sexual systems in multicellular animals, plants, and fungi. Photosynthesis causes substantial amounts of oxidative stress in photoautotrophic plants and, likewise, oxidative chemistry of polymer breakdown, cellulose and lignin, for saprotrophic fungi. In both cases, its extent precludes motility, an additional source of oxidative stress. Sessile life form and the lack of neuronal systems, however, limit options for mate recognition and adult sexual selection, resulting in inefficient mate-searching systems. Hence, sessility requires that all individuals can produce offspring, which is achieved by hermaphroditism in plants and/or by multiple mating types in fungi. In animals, motility requires neuronal systems, and muscle activity, both of which are highly sensitive to oxidative damage. As a consequence, motility has evolved in animals as heterotrophic organisms that (1) are not photosynthetically active, and (2) are not primary decomposers. Adaptations to motility provide prerequisites for an active mating behavior and efficient mate-searching systems. These benefits compensate for the "cost of males", and may explain the early evolution of sex chromosomes in metazoans. We conclude that different sexual systems evolved under the indirect physiological constraints of lifestyles.
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Affiliation(s)
- Elvira Hörandl
- Department of Systematics, Biodiversity and Evolution of Plants, University of Goettingen, Göttingen, Germany.
| | - Franz Hadacek
- Department of Plant Biochemistry, University of Goettingen, Göttingen, Germany
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80
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Barcaccia G, Palumbo F, Sgorbati S, Albertini E, Pupilli F. A Reappraisal of the Evolutionary and Developmental Pathway of Apomixis and Its Genetic Control in Angiosperms. Genes (Basel) 2020; 11:E859. [PMID: 32731368 PMCID: PMC7466056 DOI: 10.3390/genes11080859] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 07/24/2020] [Accepted: 07/27/2020] [Indexed: 12/16/2022] Open
Abstract
Apomixis sensu stricto (agamospermy) is asexual reproduction by seed. In angiosperms it represents an easy byway of life cycle renewal through gamete-like cells that give rise to maternal embryos without ploidy reduction (meiosis) and ploidy restitution (syngamy). The origin of apomixis still represents an unsolved problem, as it may be either evolved from sex or the other way around. This review deals with a reappraisal of the origin of apomixis in order to deepen knowledge on such asexual mode of reproduction which seems mainly lacking in the most basal angiosperm orders (i.e., Amborellales, Nymphaeales and Austrobaileyales, also known as ANA-grade), while it clearly occurs in different forms and variants in many unrelated families of monocots and eudicots. Overall findings strengthen the hypothesis that apomixis as a whole may have evolved multiple times in angiosperm evolution following different developmental pathways deviating to different extents from sexuality. Recent developments on the genetic control of apomixis in model species are also presented and adequately discussed in order to shed additional light on the antagonist theories of gain- and loss-of-function over sexuality.
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Affiliation(s)
- Gianni Barcaccia
- Department of Agronomy Food Natural Resources Animals Environment, University of Padova, Campus of Agripolis, Viale dell’Università 16, Legnaro, 35020 Padova, Italy;
| | - Fabio Palumbo
- Department of Agronomy Food Natural Resources Animals Environment, University of Padova, Campus of Agripolis, Viale dell’Università 16, Legnaro, 35020 Padova, Italy;
| | - Sergio Sgorbati
- Department of Environmental and Territory Sciences, University of Milano-Bicocca, Piazza della Scienza 1, 20126 Milano, Italy;
| | - Emidio Albertini
- Department of Agricultural, Food and Environmental Sciences, University of Perugia, 06121 Perugia, Italy;
| | - Fulvio Pupilli
- Research Division of Perugia, Institute of Biosciences and Bioresources, National Research Council (CNR), Via Madonna Alta 130, 06128 Perugia, Italy;
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81
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Moi D, Kilchoer L, Aguilar PS, Dessimoz C. Scalable phylogenetic profiling using MinHash uncovers likely eukaryotic sexual reproduction genes. PLoS Comput Biol 2020; 16:e1007553. [PMID: 32697802 PMCID: PMC7423146 DOI: 10.1371/journal.pcbi.1007553] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 08/12/2020] [Accepted: 05/18/2020] [Indexed: 01/09/2023] Open
Abstract
Phylogenetic profiling is a computational method to predict genes involved in the same biological process by identifying protein families which tend to be jointly lost or retained across the tree of life. Phylogenetic profiling has customarily been more widely used with prokaryotes than eukaryotes, because the method is thought to require many diverse genomes. There are now many eukaryotic genomes available, but these are considerably larger, and typical phylogenetic profiling methods require at least quadratic time as a function of the number of genes. We introduce a fast, scalable phylogenetic profiling approach entitled HogProf, which leverages hierarchical orthologous groups for the construction of large profiles and locality-sensitive hashing for efficient retrieval of similar profiles. We show that the approach outperforms Enhanced Phylogenetic Tree, a phylogeny-based method, and use the tool to reconstruct networks and query for interactors of the kinetochore complex as well as conserved proteins involved in sexual reproduction: Hap2, Spo11 and Gex1. HogProf enables large-scale phylogenetic profiling across the three domains of life, and will be useful to predict biological pathways among the hundreds of thousands of eukaryotic species that will become available in the coming few years. HogProf is available at https://github.com/DessimozLab/HogProf. Genes that are involved in the same biological process tend to co-evolve. This property is exploited by the technique of phylogenetic profiling, which identifies co-evolving (and therefore likely functionally related) genes through patterns of correlated gene retention and loss in evolution and across species. However, conventional methods to computing and clustering these correlated genes do not scale with increasing numbers of genomes. HogProf is a novel phylogenetic profiling tool built on probabilistic data structures. It allows the user to construct searchable databases containing the evolutionary history of hundreds of thousands of protein families. Such fast detection of coevolution takes advantage of the rapidly increasing amount of genomic data publicly available, and can uncover unknown biological networks and guide in-vivo research and experimentation. We have applied our tool to describe the biological networks underpinning sexual reproduction in eukaryotes.
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Affiliation(s)
- David Moi
- Department of Computational Biology, University of Lausanne, Lausanne, Switzerland
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
- SIB Swiss Institute of Bioinformatics, Lausanne, Switzerland
- * E-mail: (DM); (CD)
| | - Laurent Kilchoer
- Department of Computational Biology, University of Lausanne, Lausanne, Switzerland
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
- SIB Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Pablo S. Aguilar
- Instituto de Investigaciones Biotecnologicas (IIBIO), Universidad Nacional de San Martín, Buenos Aires, Argentina
- Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE-CONICET), Buenos Aires, Argentina
| | - Christophe Dessimoz
- Department of Computational Biology, University of Lausanne, Lausanne, Switzerland
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
- SIB Swiss Institute of Bioinformatics, Lausanne, Switzerland
- Department of Genetics, Evolution, and Environment, University College London, London, United Kingdom
- Department of Computer Science, University College London, London, United Kingdom
- * E-mail: (DM); (CD)
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82
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Hofstatter PG, Ribeiro GM, Porfírio‐Sousa AL, Lahr DJG. The Sexual Ancestor of all Eukaryotes: A Defense of the “Meiosis Toolkit”. Bioessays 2020; 42:e2000037. [DOI: 10.1002/bies.202000037] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 05/08/2020] [Indexed: 12/16/2022]
Affiliation(s)
- Paulo G. Hofstatter
- Universidade de São Paulo Instituto de Biociencias, Rua do Matão, travessa 14, A101. São Paulo, CEP.: 05508‐090, Brazil
| | - Giulia M. Ribeiro
- Universidade de São Paulo Instituto de Biociencias, Rua do Matão, travessa 14, A101. São Paulo, CEP.: 05508‐090, Brazil
| | - Alfredo L. Porfírio‐Sousa
- Universidade de São Paulo Instituto de Biociencias, Rua do Matão, travessa 14, A101. São Paulo, CEP.: 05508‐090, Brazil
| | - Daniel J. G. Lahr
- Universidade de São Paulo Instituto de Biociencias, Rua do Matão, travessa 14, A101. São Paulo, CEP.: 05508‐090, Brazil
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83
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Skejo J, Franjević D. Eukaryotes Are a Holophyletic Group of Polyphyletic Origin. Front Microbiol 2020; 11:1380. [PMID: 32714303 PMCID: PMC7343848 DOI: 10.3389/fmicb.2020.01380] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Accepted: 05/28/2020] [Indexed: 12/02/2022] Open
Affiliation(s)
- Josip Skejo
- Institute of Molecular Evolution, Heinrich–Heine University Düsseldorf, Düsseldorf, Germany
- Evolution Lab, Division of Zoology, Department of Biology, Faculty of Science, University of Zagreb, Zagreb, Croatia
| | - Damjan Franjević
- Evolution Lab, Division of Zoology, Department of Biology, Faculty of Science, University of Zagreb, Zagreb, Croatia
- *Correspondence: Damjan Franjević
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84
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Sex in Symbiodiniaceae dinoflagellates: genomic evidence for independent loss of the canonical synaptonemal complex. Sci Rep 2020; 10:9792. [PMID: 32555361 PMCID: PMC7299967 DOI: 10.1038/s41598-020-66429-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2020] [Accepted: 05/19/2020] [Indexed: 01/07/2023] Open
Abstract
Dinoflagellates of the Symbiodiniaceae family encompass diverse symbionts that are critical to corals and other species living in coral reefs. It is well known that sexual reproduction enhances adaptive evolution in changing environments. Although genes related to meiotic functions were reported in Symbiodiniaceae, cytological evidence of meiosis and fertilisation are however yet to be observed in these taxa. Using transcriptome and genome data from 21 Symbiodiniaceae isolates, we studied genes that encode proteins associated with distinct stages of meiosis and syngamy. We report the absence of genes that encode main components of the synaptonemal complex (SC), a protein structure that mediates homologous chromosomal pairing and class I crossovers. This result suggests an independent loss of canonical SCs in the alveolates, that also includes the SC-lacking ciliates. We hypothesise that this loss was due in part to permanently condensed chromosomes and repeat-rich sequences in Symbiodiniaceae (and other dinoflagellates) which favoured the SC-independent class II crossover pathway. Our results reveal novel insights into evolution of the meiotic molecular machinery in the ecologically important Symbiodiniaceae and in other eukaryotes.
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85
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Comparing Early Eukaryotic Integration of Mitochondria and Chloroplasts in the Light of Internal ROS Challenges: Timing is of the Essence. mBio 2020; 11:mBio.00955-20. [PMID: 32430475 PMCID: PMC7240161 DOI: 10.1128/mbio.00955-20] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
When trying to reconstruct the evolutionary trajectories during early eukaryogenesis, one is struck by clear differences in the developments of two organelles of endosymbiotic origin: the mitochondrion and the chloroplast. From a symbiogenic perspective, eukaryotic development can be interpreted as a process in which many of the defining eukaryotic characteristics arose as a result of mutual adaptions of both prokaryotes (an archaeon and a bacterium) involved. This implies that many steps during the bacterium-to-mitochondrion transition trajectory occurred in an intense period of dramatic and rapid changes. In contrast, the subsequent cyanobacterium-to-chloroplast development in a specific eukaryotic subgroup, leading to the photosynthetic lineages, occurred in a full-fledged eukaryote. The commonalities and differences in the two trajectories shed an interesting light on early, and ongoing, eukaryotic evolutionary driving forces, especially endogenous reactive oxygen species (ROS) formation. Differences between organellar ribosomes, changes to the electron transport chain (ETC) components, and mitochondrial codon reassignments in nonplant mitochondria can be understood when mitochondrial ROS formation, e.g., during high energy consumption in heterotrophs, is taken into account.IMPORTANCE The early eukaryotic evolution was deeply influenced by the acquisition of two endosymbiotic organelles - the mitochondrion and the chloroplast. Here we discuss the possibly important role of reactive oxygen species in these processes.
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86
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Speijer D. Debating Eukaryogenesis—Part 1: Does Eukaryogenesis Presuppose Symbiosis Before Uptake? Bioessays 2020; 42:e1900157. [DOI: 10.1002/bies.201900157] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 01/26/2020] [Indexed: 12/11/2022]
Affiliation(s)
- Dave Speijer
- Department of Medical Biochemistry, AmsterdamUMCUniversity of Amsterdam Meibergdreef 15 1105 AZ Amsterdam The Netherlands
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87
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Speijer D. Debating Eukaryogenesis—Part 2: How Anachronistic Reasoning Can Lure Us into Inventing Intermediates. Bioessays 2020; 42:e1900153. [DOI: 10.1002/bies.201900153] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 12/01/2019] [Indexed: 12/13/2022]
Affiliation(s)
- Dave Speijer
- Medical Biochemistry, Amsterdam UMCUniversity of Amsterdam Meibergdreef 15 Amsterdam AZ 1105 Netherlands
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88
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Weaver RJ. Hypothesized Evolutionary Consequences of the Alternative Oxidase (AOX) in Animal Mitochondria. Integr Comp Biol 2020; 59:994-1004. [PMID: 30912813 DOI: 10.1093/icb/icz015] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The environment in which eukaryotes first evolved was drastically different from what they experience today, and one of the key limiting factors was the availability of oxygen for mitochondrial respiration. During the transition to a fully oxygenated Earth, other compounds such as sulfide posed a considerable constraint on using mitochondrial aerobic respiration for energy production. The ancestors of animals, and those that first evolved from the simpler eukaryotes have mitochondrial respiratory components that are absent from later-evolving animals. Specifically, mitochondria of most basal metazoans have a sulfide-resistant alternative oxidase (AOX), which provides a secondary oxidative pathway to the classical cytochrome pathway. In this essay, I argue that because of its resistance to sulfide, AOX respiration was critical to the evolution of animals by enabling oxidative metabolism under otherwise inhibitory conditions. I hypothesize that AOX allowed for metabolic flexibility during the stochastic oxygen environment of early Earth which shaped the evolution of basal metazoans. I briefly describe the known functions of AOX, with a particular focus on the decreased production of reactive oxygen species (ROS) during stress conditions. Then, I propose three evolutionary consequences of AOX-mediated protection from ROS observed in basal metazoans: 1) adaptation to stressful environments, 2) the persistence of facultative sexual reproduction, and 3) decreased mitochondrial DNA mutation rates. Recognizing the diversity of mitochondrial respiratory systems present in animals may help resolve the mechanisms involved in major evolutionary processes such as adaptation and speciation.
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Affiliation(s)
- Ryan J Weaver
- Department of Biological Sciences, Auburn University, 331 Funchess Hall, Auburn, AL 36849, USA
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89
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Ji N, Huang J, Zhang Z, Zhou L, Shen X, Lin S. Identification and expression analysis of meiosis-related genes in the harmful alga Heterosigma akashiwo (Raphidophyceae). HARMFUL ALGAE 2020; 92:101736. [PMID: 32113592 DOI: 10.1016/j.hal.2019.101736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2019] [Revised: 12/20/2019] [Accepted: 12/20/2019] [Indexed: 06/10/2023]
Abstract
Sexual reproduction (SR), hallmarked by meiosis, is widespread in eukaryotes. In phytoplankton, SR has been observed in many lineages, but molecular information on SR or meiosis of harmful algal bloom (HAB) species is scarce. The raphidophyte Heterosigma akashiwo is a globally distributed and devastating HAB species, but molecular evidence of its SR or meiosis is lacking. Here, to address the gap of knowledge, the presence of meiotic genes in H. akashiwo were examined. Interestingly, seven meiosis-specific or related genes (SPO11, MND, RAD21, RAD51, MSH2, MSH6 and MEI2) were identified from H. akashiwo transcriptomes. Furthermore, expression patterns of these genes except MSH6 (excluded due to primer failure) were investigated using quantitative reverse-transcription PCR. Results showed that the examined genes exhibited similar diel rhythms, typically, highest in early dark period and then gradually decreasing until mid-day. In addition, the expression of these six genes was not higher in the stationary growth stage than in the exponential stage, as would be expected if meiosis was to form cysts, and their elevated expression in response to colchicine treatment (arresting cells in the G2/M transition) indicated a potential role of these genes in cell division and population growth in H. akashiwo. Consistent with this, we also found a morning to afternoon shift in the expression of these genes during the bloom of H. akashiwo. This study documents a part of the typical SR gene repertoire and its potential role in regulating cell division in H. akashiwo, offering candidates for population growth markers for bloom monitoring although its linkage to meiosis and SR remain to be studied further in the future.
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Affiliation(s)
- Nanjing Ji
- Jiangsu Key Laboratory of Marine Bioresources and Environment/Jiangsu Key Laboratory of Marine Biotechnology, Jiangsu Ocean University, Lianyungang, China; Co-Innovation Center of Jiangsu Marine Bio-industry Technology, Jiangsu Ocean University, Lianyungang, China; State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, Fujian, 361005, China; Department of Marine Sciences, University of Connecticut, Groton, CT, 06340, USA
| | - Jinwang Huang
- Jiangsu Key Laboratory of Marine Bioresources and Environment/Jiangsu Key Laboratory of Marine Biotechnology, Jiangsu Ocean University, Lianyungang, China; Co-Innovation Center of Jiangsu Marine Bio-industry Technology, Jiangsu Ocean University, Lianyungang, China
| | - Zhenzhen Zhang
- Jiangsu Key Laboratory of Marine Bioresources and Environment/Jiangsu Key Laboratory of Marine Biotechnology, Jiangsu Ocean University, Lianyungang, China; Co-Innovation Center of Jiangsu Marine Bio-industry Technology, Jiangsu Ocean University, Lianyungang, China
| | - Lingjie Zhou
- Department of Marine Sciences, University of Connecticut, Groton, CT, 06340, USA
| | - Xin Shen
- Jiangsu Key Laboratory of Marine Bioresources and Environment/Jiangsu Key Laboratory of Marine Biotechnology, Jiangsu Ocean University, Lianyungang, China; Co-Innovation Center of Jiangsu Marine Bio-industry Technology, Jiangsu Ocean University, Lianyungang, China
| | - Senjie Lin
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, Fujian, 361005, China; Department of Marine Sciences, University of Connecticut, Groton, CT, 06340, USA.
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90
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Affiliation(s)
- Dave Speijer
- Academic Medical Center (AMC), University of Amsterdam, Medical Biochemistry, Meibergdreef 15, 1105 AZ, Amsterdam, The Netherlands
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91
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Bloomfield G. The molecular foundations of zygosis. Cell Mol Life Sci 2020; 77:323-330. [PMID: 31203379 PMCID: PMC11105095 DOI: 10.1007/s00018-019-03187-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 05/27/2019] [Accepted: 06/06/2019] [Indexed: 10/26/2022]
Abstract
Zygosis is the generation of new biological individuals by the sexual fusion of gamete cells. Our current understanding of eukaryotic phylogeny indicates that sex is ancestral to all extant eukaryotes. Although sexual development is extremely diverse, common molecular elements have been retained. HAP2-GCS1, a protein that promotes the fusion of gamete cell membranes that is related in structure to certain viral fusogens, is conserved in many eukaryotic lineages, even though gametes vary considerably in form and behaviour between species. Similarly, although zygotes have dramatically different forms and fates in different organisms, diverse eukaryotes share a common developmental programme in which homeodomain-containing transcription factors play a central role. These common mechanistic elements suggest possible common evolutionary histories that, if correct, would have profound implications for our understanding of eukaryogenesis.
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92
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Kokko H. When Synchrony Makes the Best of Both Worlds Even Better: How Well Do We Really Understand Facultative Sex? Am Nat 2019; 195:380-392. [PMID: 32017623 DOI: 10.1086/706812] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Biological diversity abounds in potential study topics. Studies of model systems have their advantages, but reliance on a few well-understood cases may create false impressions of what biological phenomena are the norm. Here I focus on facultative sex, which is often hailed as offering the best of both worlds, in that rare sex offers benefits almost equal to obligate sex and avoids paying most of the demographic costs. How well do we understand when and why this form of sexual reproduction is expected to prevail? I show several gaps in the theoretical literature and, by contrasting asynchronous with synchronous sex, highlight the need to link sex theories to the theoretical underpinnings of bet hedging, on the one hand, and to mate limitation considerations, on the other. Condition-dependent sex and links between sex with dispersal or dormancy appear understudied. While simplifications are justifiable as a simple assumption structure enhances analytical tractability, much remains to be done to incorporate key features of real sex to the main theoretical edifice.
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93
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Maciver SK, Koutsogiannis Z, de Obeso Fernández Del Valle A. 'Meiotic genes' are constitutively expressed in an asexual amoeba and are not necessarily involved in sexual reproduction. Biol Lett 2019; 15:20180871. [PMID: 30836881 DOI: 10.1098/rsbl.2018.0871] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The amoebae (and many other protists) have traditionally been considered as asexual organisms, but suspicion has been growing that these organisms are cryptically sexual or are at least related to sexual lineages. This contention is mainly based on genome studies in which the presence of 'meiotic genes' has been discovered. Using RNA-seq (next-generation shotgun sequencing, identifying and quantifying the RNA species in a sample), we have found that the entire repertoire of meiotic genes is expressed in exponentially growing Acanthamoeba and we argue that these so-called meiotic genes are involved in the related process of homologous recombination in this amoeba. We contend that they are only involved in meiosis in other organisms that indulge in sexual reproduction and that homologous recombination is important in asexual protists as a guard against the accumulation of mutations. We also suggest that asexual reproduction is the ancestral state.
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Affiliation(s)
- Sutherland K Maciver
- Centre for Discovery Brain Sciences, Edinburgh Medical School, Biomedical Sciences, University of Edinburgh , Hugh Robson Building, George Square, Edinburgh EH8 9XD , UK
| | - Zisis Koutsogiannis
- Centre for Discovery Brain Sciences, Edinburgh Medical School, Biomedical Sciences, University of Edinburgh , Hugh Robson Building, George Square, Edinburgh EH8 9XD , UK
| | - Alvaro de Obeso Fernández Del Valle
- Centre for Discovery Brain Sciences, Edinburgh Medical School, Biomedical Sciences, University of Edinburgh , Hugh Robson Building, George Square, Edinburgh EH8 9XD , UK
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94
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Maciver SK. Ancestral Eukaryotes Reproduced Asexually, Facilitated by Polyploidy: A Hypothesis. Bioessays 2019; 41:e1900152. [DOI: 10.1002/bies.201900152] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 10/10/2019] [Indexed: 12/29/2022]
Affiliation(s)
- Sutherland K. Maciver
- Centre for Discovery Brain Sciences, Edinburgh Medical SchoolBiomedical SciencesUniversity of Edinburgh Hugh Robson Building, George Square Edinburgh EH8 9XD Scotland UK
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95
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Gilbert SF. Evolutionary transitions revisited: Holobiont evo-devo. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2019; 332:307-314. [PMID: 31565856 DOI: 10.1002/jez.b.22903] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 08/07/2019] [Accepted: 08/10/2019] [Indexed: 12/14/2022]
Abstract
John T. Bonner lists four essential transformations in the evolution of life: the emergence of the eukaryotic cell, meiosis, multicellularity, and the nervous system. This paper analyses the mechanisms for those transitions in light of three of Dr. Bonner's earlier hypotheses: (a) that the organism is its life cycle, (b) that evolution consists of alterations of the life cycle, and (c) that development extends beyond the body and into interactions with other organisms. Using the notion of the holobiont life cycle, this paper attempts to show that these evolutionary transitions can be accomplished through various means of symbiosis. Perceiving the organism both as an interspecies consortium and as a life cycle supports a twofold redefinition of the organism as a holobiont constructed by integrating together the life cycles of several species. These findings highlight the importance of symbiosis and the holobiont development in analyses of evolution.
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Affiliation(s)
- Scott F Gilbert
- Department of Biology, Swarthmore College, Swarthmore, Pennsylvania
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96
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Wideman JG, Novick A, Muñoz-Gómez SA, Doolittle WF. Neutral evolution of cellular phenotypes. Curr Opin Genet Dev 2019; 58-59:87-94. [PMID: 31574422 DOI: 10.1016/j.gde.2019.09.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 09/09/2019] [Accepted: 09/11/2019] [Indexed: 12/29/2022]
Abstract
Eukaryotes exhibit a great diversity of cellular and subcellular morphologies, but their basic underlying architecture is fairly constant. All have a nucleus, Golgi, cytoskeleton, plasma membrane, vesicles, ribosomes, and all known lineages but one have mitochondrion-related organelles. Moreover, most eukaryotes undergo processes such as mitosis, meiosis, DNA recombination, and often perform feats such as phagocytosis, and amoeboid and flagellar movement. With all of these commonalities, it is obvious that eukaryotes evolved from a common ancestor, but it is not obvious how eukaryotes came to have their diverse structural phenotypes. Are these phenotypes adaptations to particular niches, their evolution dominated by positive natural selection? Or is eukaryotic cellular diversity substantially the product of neutral evolutionary processes, with adaptation either illusory or a secondary consequence? In this paper, we outline how a hierarchical view of phenotype can be used to articulate a neutral theory of phenotypic evolution, involving processes such as gene loss, gene replacement by homologues or analogues, gene duplication followed by subfunctionalization, and constructive neutral evolution. We suggest that neutral iterations of these processes followed by entrenchment of their products can explain much of the diversity of cellular, developmental, and biochemical phenotypes of unicellular eukaryotes and should be explored in addition to adaptive explanations.
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Affiliation(s)
- Jeremy G Wideman
- Centre for Mechanisms of Evolution, Arizona State University, Tempe, AZ, 85287, USA; Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, Nova Scotia, B3H 4R2, Canada.
| | - Aaron Novick
- Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, Nova Scotia, B3H 4R2, Canada; Department of Philosophy, Dalhousie University, Halifax, Nova Scotia, B3H 4R2, Canada; Department of Philosophy, Purdue University, West Lafayette, IN, 47907, USA
| | - Sergio A Muñoz-Gómez
- Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, Nova Scotia, B3H 4R2, Canada
| | - W Ford Doolittle
- Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, Nova Scotia, B3H 4R2, Canada
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97
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A 'parameiosis' drives depolyploidization and homologous recombination in Candida albicans. Nat Commun 2019; 10:4388. [PMID: 31558727 PMCID: PMC6763455 DOI: 10.1038/s41467-019-12376-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 08/28/2019] [Indexed: 12/14/2022] Open
Abstract
Meiosis is a conserved tenet of sexual reproduction in eukaryotes, yet this program is seemingly absent from many extant species. In the human fungal pathogen Candida albicans, mating of diploid cells generates tetraploid products that return to the diploid state via a non-meiotic process of depolyploidization known as concerted chromosome loss (CCL). Here, we report that recombination rates are more than three orders of magnitude higher during CCL than during normal mitotic growth. Furthermore, two conserved ‘meiosis-specific’ factors play central roles in CCL as SPO11 mediates DNA double-strand break formation while both SPO11 and REC8 regulate chromosome stability and promote inter-homolog recombination. Unexpectedly, SPO11 also promotes DNA repair and recombination during normal mitotic divisions. These results indicate that C. albicans CCL represents a ‘parameiosis’ that blurs the conventional boundaries between mitosis and meiosis. They also reveal parallels with depolyploidization in mammalian cells and provide potential insights into the evolution of meiosis. Mating of Candida albicans produces tetraploid products that return to the diploid state via a non-meiotic process known as concerted chromosome loss (CCL). Here, Anderson et al. show high recombination rates during CCL and identify factors that are essential for chromosome stability and recombination during CCL.
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98
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Burke NW, Bonduriansky R. The paradox of obligate sex: The roles of sexual conflict and mate scarcity in transitions to facultative and obligate asexuality. J Evol Biol 2019; 32:1230-1241. [DOI: 10.1111/jeb.13523] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2019] [Revised: 08/04/2019] [Accepted: 08/12/2019] [Indexed: 11/27/2022]
Affiliation(s)
- Nathan W. Burke
- Evolution and Ecology Research Centre School of Biological, Earth and Environmental Sciences University of New South Wales Sydney Sydney NSW Australia
| | - Russell Bonduriansky
- Evolution and Ecology Research Centre School of Biological, Earth and Environmental Sciences University of New South Wales Sydney Sydney NSW Australia
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99
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Abstract
Algae are photosynthetic eukaryotes whose taxonomic breadth covers a range of life histories, degrees of cellular and developmental complexity, and diverse patterns of sexual reproduction. These patterns include haploid- and diploid-phase sex determination, isogamous mating systems, and dimorphic sexes. Despite the ubiquity of sexual reproduction in algae, their mating-type-determination and sex-determination mechanisms have been investigated in only a limited number of representatives. These include volvocine green algae, where sexual cycles and sex-determining mechanisms have shed light on the transition from mating types to sexes, and brown algae, which are a model for UV sex chromosome evolution in the context of a complex haplodiplontic life cycle. Recent advances in genomics have aided progress in understanding sexual cycles in less-studied taxa including ulvophyte, charophyte, and prasinophyte green algae, as well as in diatoms.
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Affiliation(s)
- James Umen
- Donald Danforth Plant Science Center, St. Louis, Missouri 63132, USA;
| | - Susana Coelho
- Algal Genetics Group, Integrative Biology of Marine Models, Station Biologique de Roscoff, Sorbonne Université, UPMC Université Paris 06, CNRS, CS 90074, F-29688 Roscoff, France;
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100
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Genetic and genomic evolution of sexual reproduction: echoes from LECA to the fungal kingdom. Curr Opin Genet Dev 2019; 58-59:70-75. [PMID: 31473482 DOI: 10.1016/j.gde.2019.07.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 06/28/2019] [Accepted: 07/16/2019] [Indexed: 12/30/2022]
Abstract
Sexual reproduction is vastly diverse and yet highly conserved across the eukaryotic domain. This ubiquity suggests that the last eukaryotic common ancestor (LECA) was sexual. It is hypothesized that several critical processes in sexual reproduction, including cell fusion and meiosis, were acquired during the evolution from the first eukaryotic common ancestor (FECA) to the sexual LECA. However, it is challenging to delineate the exact origin and evolution of sexual reproduction given that both FECA and LECA are extinct. Studies of diverse eukaryotes have helped to shed light on this sexual evolutionary trajectory, revealing that a primordial sexual ploidy cycle likely involved endoreplication followed by concerted chromosome loss and that cell-cell fusion, meiosis, and sex determination later arose to shape modern sexual reproduction. Despite the general conservation of sexual reproduction processes throughout eukaryotes, modern sexual cycles are immensely diverse and complex. This diversity and complexity has become readily apparent in the fungal kingdom with the recent rapid expansion of whole-genome sequencing. This abundance of data, the variety of genetic tools available to manipulate and characterize fungi, and the thorough characterization of many fungal sexual cycles make the fungal kingdom an excellent forum, in which to study the conservation and diversification of sexual reproduction.
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