DOCSLIB.ORG

What Causes Inefficient Transmission of Male-Killing Wolbachia in Drosophila?

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
What Causes Inefficient Transmission of Male-Killing Wolbachia in Drosophila? Heredity 87 (2001) 220±226 Received 23 March 2001, accepted 10 May 2001 What causes inef®cient transmission of male-killing Wolbachia in Drosophila? GREGORY D. D. HURST* , FRANCIS M. JIGGINS à & SARAH J. W. ROBINSON Department of Biology, University College London, 4 Stephenson Way, London NW1 2HE, U.K. and àDepartment of Genetics, Downing Street, Cambridge, CB2 3EH, U.K. Sel®sh genetic elements that distort the sex ratio are common in arthropods. Theory predicts they will invade and spread to ®xation if they are vertically transmitted with perfect ®delity, potentially leading to host extinction. For inherited microorganisms that distort the sex ratio, inecient vertical transmission or incomplete sex ratio distorting ability is required for host persistence. However, the relative roles of genetic and environmental factors in permitting the survival of male hosts and preventing parasite transmission are poorly understood. We examined the causes of transmission in®delity and male survival for a male-killing Wolbachia strain in Drosophila bifasciata. Under standard laboratory conditions (18°C), in its standard genetic background, males are produced very rarely, and no case of reversion has been observed in 20 generations of laboratory rearing. To investigate the role of host genetic factors, Wolbachia was crossed into 27 dierent inbred lines of D. bifasciata, but in no case was reversion observed at preferred environmental temperatures. The role of elevated temperature in inducing inecient transmission was examined. Whilst vertical transmis- sion was perfect over three generations of maintenance at 23.5°, transmission in®delity was observed at 25°. We conclude that there is no evidence for the presence of either ®xed or polymorphic host genes that repress transmission at standard environmental temperatures. However, severe tempera- ture treatment does make vertical transmission imperfect. We suggest that the case of Wolbachia in D. bifasciata is one that is naturally balanced, the population being maintained polymorphic without the evolution of host resistance genes. Keywords: Drosophila, male killing, parasite resistance, sel®sh genetic elements, Wolbachia. 1997). Second, there are strains of both Wolbachia and Introduction members of the Microspora which alter the sex deter- It is now recognized that a large number of arthropods mination of their host, promoting female development are host to sel®sh genetic elements that distort the sex of hosts that would otherwise be male (Rigaud, 1997). ratio (Hurst et al., 1996). These are of two types. First, Lastly, there are a number of bacteria that kill male there are the cases of meiotic drive associated with sex hosts during embryogenesis (Hurst & Jiggins, 2000). chromosomes. Here, one of the sex chromosome gains a Hamilton (1967) recognized that sel®sh genetic ele- transmission advantage during male meiosis, such that it ments that distort the sex ratio are in an interesting is inherited by more than half of the progeny of a male evolutionary position. If the ecological and biological (Lyttle, 1991). Second, there are cases of maternally circumstances permit, they may become ®xed within the inherited agents that have evolved to distort the sex ratio population and cause the extinction of both themselves of their host away from the production of male ospring and their host. Indeed, ®xation of Wolbachia that induce (which cannot transmit them) towards the production of host parthenogenesis is known, whole species being female ospring (Hurst et al., 1997). Three dierent converted to asexuality (Zchori-Fein et al., 1992). For a types of cytoplasmic sex ratio distorters are known in microorganism that distorts host sex ratio rather than arthropods. First, strains of Wolbachia are known which sexuality, this situation would correspond to host induce host parthenogenesis, through doubling the extinction. chromosome complement of haploid males in haplodip- Evolutionary biologists have therefore asked what loid hosts (Stouthamer & Kazmer, 1994; Stouthamer, factors prevent sel®sh genetic elements that distort the sex ratio from going to ®xation, that is to say what factors maintain these elements balanced within the *Correspondence. E-mail: [email protected] 220 Ó 2001 The Genetics Society of Great Britain. TRANSMISSION OF WOLBACHIA IN DROSOPHILA 221 population (Carvalho & Vaz, 1999). Two types of transmitted in each of 10 inbred lines he maintained in scenario are envisaged. First, there are cases in which the the laboratory. sel®sh genetic element is naturally balanced. That is to In this study we extended Ikeda's (1970) observation say, the element remains polymorphic in the population by testing a further 27 inbred lines. Following this, we without host evolution. In the case of meiotic drive in looked for evidence of environmental eects on trans- Drosophila pseudoobscura, for instance, the eect of mission ®delity. We show that exposure to elevated increased requirement for sperm that follows from temperatures reduced transmission ®delity when tem- female-biased population sex ratios is considered to perature was maintained above 25° over all life history impose selection on male virility and prevent the driving stages. The lack of resistance genes, and the potential for X chromosome (which reduces sperm production) elevated temperatures to induce transmission in®delity becoming ®xed in the population (Policansky, 1979). suggest that this system is balanced by environmental For inherited microorganisms that distort the sex ratio, factors rather than by polymorphic host genes. These natural balance may follow from inecient transmission results are discussed in the context of other sex ratio of the element due to environmental in¯uences on distorting inherited microorganisms and sel®sh genetic microorganism survival. A variety of studies have elements in general. demonstrated elevated environmental temperature reduce either the transmission eciency of Wolbachia Methods or the penetrance of its reproduction manipulation phenotypes (Homann et al., 1986; Stevens, 1989; General methods Rigaud et al., 1991; Pintureau et al., 1999; van Opijnen & Breeuwer, 1999). Other studies have suggested a role Drosophila bifasciata were collected from Japan in 1998 for naturally occurring antibiotics in reducing Wolba- as described in Hurst et al. (2000). Eighty isofemale lines chia transmission rates (Stevens & Wicklow, 1992). were established, ®ve of which were observed to bear Second, there are cases where natural balance is lacking. male-killing Wolbachia. Members of the other 75 lines Here, the element would become ®xed were it not for were pooled into a population and maintained at high host evolution. It is selection for host genes preventing population size (>1000 ¯ies) to prevent loss of genetic the action or transmission of the element that maintains variation. These ¯ies were bred on modi®ed corn-meal the element polymorphic in the host population. Genes agar, as in Hurst et al. (2000). that repress the distorting ability of driving X chromo- somes are well known in a variety of systems, and Establishment of host environmental resistance to driving genes is more common than temperature `natural balance' for genes inducing drive (Carvalho & Vaz, 1999). The optimal conditions for ¯y development were As yet there are insucient case studies to assess the reasoned to be those at which development was quick relative frequency with which inherited microorganisms but mortality low. To ascertain the optimal temperature, that distort the sex ratio are balanced by environmental outbred ¯ies were allowed to oviposit at 21°C, and and host genetic factors. Whilst it is clear that genes replicates of 25 1st instar larvae picked to vials main- preventing parasite transmission are important in cer- tained at 18°,21°,25° and 27°, and at 70% RH. This tain cases (Cavalcanti et al., 1957; Rigaud & Juchault, was repeated for four dierent groups of ovipositing 1992), there is little data on the extent to which `natural females. Time to emergence and survivorship to the balance' exists. We therefore examined the causes of adult stage were scored. inecient transmission of the male-killing Wolbachia in Drosophila bifasciata (Hurst et al., 2000). Drosophila Genetic variation for parasite transmission bifasciata is a temperate zone ¯y that breeds predom- inantly in sap ¯uxes. The bacterium is present in The genetic variation present in our outbred population between 0 and 7% of females from wild populations of ¯ies was converted into between-line variation (Ikeda, 1970), suggesting that the factors inducing through inbreeding. In brief, virgin females were taken Wolbachia loss will be of detectable magnitude. Initially, from the outbred Japanese population, crossed to a we looked for evidence of polymorphic host factors single male and allowed to produce ospring. The new preventing the transmission or action of this bacterium. generation was then established from individual bro- Laboratory study of Wolbachia in D. bifasciata has ther±sister crosses over a period of six generations, such shown it to be transmitted with perfect ®delity on the that over 50% of heterozygous loci in the original pair standard host genetic background (Ikeda, 1970). Ikeda of ¯ies were converted to being homozygous. Overall, (1970) further noted that the bacterium was faithfully inbred lines from 25 founder pairs were constructed, and Ó The Genetics Society of Great Britain, Heredity, 87, 220±226. 222 G. D. D. HURST ET AL. these were augmented
Load more

Recommended publications
  • Wolbachia-Mitochondrial DNA Associations in Transitional Populations of Rhagoletis Cerasi
    insects Communication Wolbachia-Mitochondrial DNA Associations in Transitional Populations of Rhagoletis cerasi 1, , 1 1, 2, Vid Bakovic * y , Martin Schebeck , Christian Stauffer z and Hannes Schuler z 1 Department of Forest and Soil Sciences, University of Natural Resources and Life Sciences Vienna, BOKU, Peter-Jordan-Strasse 82/I, A-1190 Vienna, Austria; [email protected] (M.S.); christian.stauff[email protected] (C.S.) 2 Faculty of Science and Technology, Free University of Bozen-Bolzano, Universitätsplatz 5, I-39100 Bozen-Bolzano, Italy; [email protected] * Correspondence: [email protected]; Tel.: +43-660-7426-398 Current address: Department of Biology, IFM, University of Linkoping, Olaus Magnus Vag, y 583 30 Linkoping, Sweden. Equally contributing senior authors. z Received: 29 August 2020; Accepted: 3 October 2020; Published: 5 October 2020 Simple Summary: Wolbachia is an endosymbiotic bacterium that infects numerous insects and crustaceans. Its ability to alter the reproduction of hosts results in incompatibilities of differentially infected individuals. Therefore, Wolbachia has been applied to suppress agricultural and medical insect pests. The European cherry fruit fly, Rhagoletis cerasi, is mainly distributed throughout Europe and Western Asia, and is infected with at least five different Wolbachia strains. The strain wCer2 causes incompatibilities between infected males and uninfected females, making it a potential candidate to control R. cerasi. Thus, the prediction of its spread is of practical importance. Like mitochondria, Wolbachia is inherited from mother to offspring, causing associations between mitochondrial DNA and endosymbiont infection. Misassociations, however, can be the result of imperfect maternal transmission, the loss of Wolbachia, or its horizontal transmission from infected to uninfected individuals.
    [Show full text]
  • Research Techniques in Animal Ecology
    Research Techniques in Animal Ecology Methods and Cases in Conservation Science Mary C. Pearl, Editor Methods and Cases in Conservation Science Tropical Deforestation: Small Farmers and Land Clearing in the Ecuadorian Amazon Thomas K. Rudel and Bruce Horowitz Bison: Mating and Conservation in Small Populations Joel Berger and Carol Cunningham, Population Management for Survival and Recovery: Analytical Methods and Strategies in Small Population Conservation Jonathan D. Ballou, Michael Gilpin, and Thomas J. Foose, Conserving Wildlife: International Education and Communication Approaches Susan K. Jacobson Remote Sensing Imagery for Natural Resources Management: A First Time User’s Guide David S. Wilkie and John T. Finn At the End of the Rainbow? Gold, Land, and People in the Brazilian Amazon Gordon MacMillan Perspectives in Biological Diversity Series Conserving Natural Value Holmes Rolston III Series Editor, Mary C. Pearl Series Advisers, Christine Padoch and Douglas Daly Research Techniques in Animal Ecology Controversies and Consequences Luigi Boitani and Todd K. Fuller Editors C COLUMBIA UNIVERSITY PRESS NEW YORK Columbia University Press Publishers Since 1893 New York Chichester, West Sussex Copyright © 2000 by Columbia University Press All rights reserved Library of Congress Cataloging-in-Publication Data Research techniques in animal ecology : controversies and consequences / Luigi Boitani and Todd K. Fuller, editors. p. cm. — (Methods and cases in conservation science) Includes bibliographical references (p. ). ISBN 0–231–11340–4 (cloth : alk. paper)—ISBN 0–231–11341–2 (paper : alk. paper) 1. Animal ecology—Research—Methodology. I. Boitani, Luigi. II. Fuller, T. K. III. Series. QH541.2.R47 2000 591.7′07′2—dc21 99–052230 ϱ Casebound editions of Columbia University Press books are printed on permanent and durable acid-free paper.
    [Show full text]
  • Metazoan Ribosome Inactivating Protein Encoding Genes Acquired by Horizontal Gene Transfer Received: 30 September 2016 Walter J
    www.nature.com/scientificreports OPEN Metazoan Ribosome Inactivating Protein encoding genes acquired by Horizontal Gene Transfer Received: 30 September 2016 Walter J. Lapadula1, Paula L. Marcet2, María L. Mascotti1, M. Virginia Sanchez-Puerta3 & Accepted: 5 April 2017 Maximiliano Juri Ayub1 Published: xx xx xxxx Ribosome inactivating proteins (RIPs) are RNA N-glycosidases that depurinate a specific adenine residue in the conserved sarcin/ricin loop of 28S rRNA. These enzymes are widely distributed among plants and their presence has also been confirmed in several bacterial species. Recently, we reported for the first timein silico evidence of RIP encoding genes in metazoans, in two closely related species of insects: Aedes aegypti and Culex quinquefasciatus. Here, we have experimentally confirmed the presence of these genes in mosquitoes and attempted to unveil their evolutionary history. A detailed study was conducted, including evaluation of taxonomic distribution, phylogenetic inferences and microsynteny analyses, indicating that mosquito RIP genes derived from a single Horizontal Gene Transfer (HGT) event, probably from a cyanobacterial donor species. Moreover, evolutionary analyses show that, after the HGT event, these genes evolved under purifying selection, strongly suggesting they play functional roles in these organisms. Ribosome inactivating proteins (RIPs, EC 3.2.2.22) irreversibly modify ribosomes through the depurination of an adenine residue in the conserved alpha-sarcin/ricin loop of 28S rRNA1–4. This modification prevents the binding of elongation factor 2 to the ribosome, arresting protein synthesis5, 6. The occurrence of RIP genes has been exper- imentally confirmed in a wide range of plant taxa, as well as in several species of Gram positive and Gram negative bacteria7–9.
    [Show full text]
  • Finnegan Thesis Minus Appendices
    The effect of sex-ratio meiotic drive on sex, survival, and size in the Malaysian stalk-eyed fly, Teleopsis dalmanni Sam Ronan Finnegan A dissertation submitted in partial fulfilment of the requirements of the degree of Doctor of Philosophy University College London 26th February 2020 1 I, Sam Ronan Finnegan, confirm that the work presented in this thesis is my own. Where information has been derived from other sources, I confirm that this has been indicated in the thesis. 2 Acknowledgements Thank you first of all to Natural Environment Research Council (NERC) for funding this PhD through the London NERC DTP, and also supporting my work at the NERC Biomolecular Analysis Facility (NBAF) via a grant. Thank you to Deborah Dawson, Gav Horsburgh and Rachel Tucker at the NBAF for all of their help. Thanks also to ASAB and the Genetics Society for funding two summer students who provided valuable assistance and good company during busy experiments. Thank you to them – Leslie Nitsche and Kiran Lee – and also to a number of undergraduate project students who provided considerable support – Nathan White, Harry Kelleher, Dixon Koh, Kiran Lee, and Galvin Ooi. It was a pleasure to work with you all. Thank you also to all of the members of the stalkie lab who have come before me. In particular I would like to thank Lara Meade, who has always been there for help and advice. Special thanks also to Flo Camus for endless aid and assistance when it came to troubleshooting molecular work. Thank you to the past and present members of the Drosophila group – Mark Hill, Filip Ruzicka, Flo Camus, and Michael Jardine.
    [Show full text]
  • A Ribosome-Inactivating Protein in a Drosophila Defensive Symbiont
    A ribosome-inactivating protein in a Drosophila defensive symbiont Phineas T. Hamiltona,1, Fangni Pengb, Martin J. Boulangerb, and Steve J. Perlmana,c,1 aDepartment of Biology, University of Victoria, Victoria, BC, Canada V8W 2Y2; bDepartment of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada V8P 5C2; and cIntegrated Microbial Biodiversity Program, Canadian Institute for Advanced Research, Toronto, ON, Canada M5G 1Z8 Edited by Nancy A. Moran, University of Texas at Austin, Austin, TX, and approved November 24, 2015 (received for review September 18, 2015) Vertically transmitted symbionts that protect their hosts against the proximate causes of defense are largely unknown, although parasites and pathogens are well known from insects, yet the recent studies have provided some intriguing early insights: A underlying mechanisms of symbiont-mediated defense are largely Pseudomonas symbiont of rove beetles produces a polyketide unclear. A striking example of an ecologically important defensive toxin thought to deter predation by spiders (14), Streptomyces symbiosis involves the woodland fly Drosophila neotestacea, symbionts of beewolves produce antibiotics to protect the host which is protected by the bacterial endosymbiont Spiroplasma from fungal infection (17), and bacteriophages encoding putative when parasitized by the nematode Howardula aoronymphium. toxins are required for Hamiltonella defensa to protect its aphid The benefit of this defense strategy has led to the rapid spread host from parasitic wasps (18),
    [Show full text]
  • The Drosophila Baramicin Polypeptide Gene Protects Against Fungal 2 Infection
    bioRxiv preprint doi: https://doi.org/10.1101/2020.11.23.394148; this version posted February 1, 2021. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC 4.0 International license. 1 The Drosophila Baramicin polypeptide gene protects against fungal 2 infection 3 4 M.A. Hanson1*, L.B. Cohen2, A. Marra1, I. Iatsenko1,3, S.A. Wasserman2, and B. 5 Lemaitre1 6 7 1 Global Health Institute, School of Life Science, École Polytechnique Fédérale de 8 Lausanne (EPFL), Lausanne, Switzerland. 9 2 Division of Biological Sciences, University of California San Diego (UCSD), La Jolla, 10 California, United States of America. 11 3 Max Planck Institute for Infection Biology, 10117, Berlin, Germany. 12 * Corresponding author: M.A. Hanson ([email protected]), B. Lemaitre 13 ([email protected]) 14 15 ORCID IDs: 16 Hanson: https://orcid.org/0000-0002-6125-3672 17 Cohen: https://orcid.org/0000-0002-6366-570X 18 Iatsenko: https://orcid.org/0000-0002-9249-8998 19 Wasserman: https://orcid.org/0000-0003-1680-3011 20 Lemaitre: https://orcid.org/0000-0001-7970-1667 21 22 Abstract 23 The fruit fly Drososphila melanogaster combats microBial infection by 24 producing a battery of effector peptides that are secreted into the haemolymph. 25 Technical difficulties prevented the investigation of these short effector genes until 26 the recent advent of the CRISPR/CAS era. As a consequence, many putative immune 27 effectors remain to Be characterized and exactly how each of these effectors 28 contributes to survival is not well characterized.
    [Show full text]
  • Evolution of Gene Regulation Among Drosophila Species
    8th Annual ARTHROPOD GENOMICS SYMPOSIUM (AGS) ABSTRACTS | INVITED SPEAKERS EVOLUTION OF GENE REGULATION AMONG DROSOPHILA SPECIES Patricia Wittkopp, University of Michigan Genetic dissection of phenotypic differences within and between species has shown that genetic changes affecting the regulation of gene expression are an important source of phenotypic diversity. We have seen this in our own work investigating the genetic basis of pigmentation differences between closely related Drosophila species. To better understand the genetic mechanisms responsible for the evolution of gene expression, we have been investigating the evolution of a specific gene yellow( ) as well as the evolution of gene expression on a genomic scale. Work on both of these topics, with an emphasis on methods adaptable to non-model systems, will be presented. METAMORPHOSIS AND EVOLUTION OF ARTHROPOD GENOMICS Judith H. Willis, University of Georgia I began work on arthropod genomics 50 years ago. At first, I was only interested in the genetic underpinnings of metamorphic transitions, but I have ended up with an increasing orientation toward arthropod evolution. During those 50 years the field itself has evolved (gaining a name in the process) and metamorphosed (witness this meeting). My talk will address both the biology and the history. I began by testing whether each metamorphic stage was underwritten by a unique set of genes by using cuticular proteins (CPs) as molecular markers. Results, starting with tube gels and progressing to the isolation and characterization of two CP genes and their promoters, demolished that hypothesis. A shift from a giant silkworm to Anopheles gambiae that devotes ~2% of its protein coding genes to structural CPs was accompanied by a larger scale analysis of their activity, including mRNA expression and recovery of authentic CPs from cuticle determined by LC-MS/MS analyses.
    [Show full text]
  • Metazoan Ribotoxin Genes Acquired by Horizontal Gene Transfer
    bioRxiv preprint doi: https://doi.org/10.1101/071340; this version posted August 26, 2016. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. Metazoan ribotoxin genes acquired by Horizontal Gene Transfer Walter J. Lapadula1*, Paula L. Marcet2, María L. Mascotti1, María V. Sánchez Puerta3, Maximiliano Juri Ayub1* 1. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis, IMIBIO-SL-CONICET and Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, San Luis Argentina. 2. Centers for Disease Control and Prevention, Division of Parasitic Diseases and Malaria, Atlanta, USA. 3. Instituto de Ciencias Básicas, IBAM-CONICET and Facultad de Ciencias Agrarias, Universidad Nacional de Cuyo, Mendoza, Argentina. *Corresponding authors: [email protected], [email protected] 1 bioRxiv preprint doi: https://doi.org/10.1101/071340; this version posted August 26, 2016. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. Abstract Ribosome inactivating proteins (RIPs) are RNA N-glycosidases that depurinate a specific adenine residue in the conserved sarcin/ricin loop of 28S rRNA. These enzymes are widely distributed among plants and their presence has also been confirmed in several bacterial species. Recently, we reported for the first time in silico evidence of RIP encoding genes in metazoans, in two closely related species of insects: Aedes aegypti and Culex quinquefasciatus.
    [Show full text]
  • The Drosophila Baramicin Polypeptide Gene Protects Against Fungal 2 Infection
    bioRxiv preprint doi: https://doi.org/10.1101/2020.11.23.394148; this version posted December 1, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC 4.0 International license. 1 The Drosophila Baramicin polypeptide gene protects against fungal 2 infection 3 4 M.A. Hanson1*, L.B. Cohen2, A. Marra1, I. Iatsenko1,3, S.A. Wasserman2, and B. 5 Lemaitre1 6 7 1 Global Health Institute, School of Life Science, École Polytechnique Fédérale de 8 Lausanne (EPFL), Lausanne, Switzerland. 9 2 Division of Biological Sciences, University of California San Diego (UCSD), La Jolla, 10 California, United States of America. 11 3 Max Planck Institute for Infection Biology, 10117, Berlin, Germany. 12 * Corresponding author: M.A. Hanson ([email protected]), B. Lemaitre 13 ([email protected]) 14 15 ORCID IDs: 16 Hanson: https://orcid.org/0000-0002-6125-3672 17 Cohen: https://orcid.org/0000-0002-6366-570X 18 Iatsenko: https://orcid.org/0000-0002-9249-8998 19 Wasserman: https://orcid.org/0000-0003-1680-3011 20 Lemaitre: https://orcid.org/0000-0001-7970-1667 21 22 Abstract (212 words) 23 The fruit fly Drososphila melanogaster combats microBial infection by 24 producing a battery of effector peptides that are secreted into the haemolymph. The 25 existence of many effectors that redundantly contribute to host defense has 26 hampered their functional characterization. As a consequence, the logic underlying 27 the role of immune effectors is only poorly defined, and exactly how each gene 28 contributes to survival is not well characterized.
    [Show full text]
  • VOL. 24 September- Septembre, 199 ENTOMOLOGICAL SOCIETY OF
    ENTOMOLOGICAL SOCIETY OF CANADA LA D'ENTOMOLOGIE DU CANADA BULLETIN VOL. 24 September- septembre, 199 VOL 24(3) - September I septembre, 1992 Addendum -Joint Annual Meeting of ESC & ESS Guest Editorials .......... ........................................... .................................................................................. 102 LadiesandGentlemen:theBiodome -C. Vincent The Worsening Crisis in Biology -J. Heraty ............... ......................... ................. .. ................ .... ...... 103 <:,· Society Business I Affaires de Ia Societe <b• President's Update- R.A. Ring Meeting Notices (1993 Annual Meeting) ........ .. .. ... .. ...... ... .. ... .. .. .. .. ... ... .......... ............ ..... ... ............. 105 Call for Nominations - Honorary Membership ElectionsCommittee/Le ComitedesElections ............................................................ .. ........ .. ... ......... 105 CFBS Nominations Fellow of the ESC To Student Members of the ESC/Aux membres etudiants de Ia SEC .............. .................. ............... 106 Questionnaire (fran'<ais/english) Achievement Awards Committee - Call for Nominations .. .. ..... ... ... ......... .. .. ..... ....... ... ..................... I 09 Members in the News .... .. .. ....... ............... ...... ........... .. ............................................. .... ... ............ .. ... ..... ... Ill "Entomology in Canada"/"L 'Entomologie au Canada" Brochures ......................... .. ............ ..... ... .... ... 142 Advertisement Membership
    [Show full text]
  • X-Linked Meiotic Drive Boosts Population Size and Persistence
    bioRxiv preprint doi: https://doi.org/10.1101/2020.06.05.137224; this version posted June 6, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. GENETICS | INVESTIGATION X-linked meiotic drive boosts population size and persistence Carl Mackintosh∗,†, Andrew Pomiankowski∗,†,1 and Michael F Scott∗,‡ ∗Department of Genetics, Evolution and Environment, University College London, London, UK, †CoMPLEX, University College London, London, UK, ‡Genetics Institute, Department of Genetics, Evolution and Environment, University College London, London, UK 1 ABSTRACT X-linked meiotic drivers cause X-bearing sperm to be produced in excess by male carriers, leading to female-biased 2 sex ratios. Selection for these selfish sex chromosomes can lead to completely female populations, which cannot produce 3 offspring and go extinct. However, at the population level, moderately female-biased sex ratios are optimal because relatively 4 few males are required to fertilise all the females. We develop eco-evolutionary models for sex-linked meiotic drive alleles to 5 investigate their full range of demographic effects. We find general conditions for the spread and fixation of X-drivers, accounting 6 for transmission bias and other factors associated with the spread of X-drivers such as sperm competition and polyandry. Our 7 results suggest driving X-alleles that do not reach fixation (or do not bias segregation excessively) will boost population sizes 8 and persistence times by increasing population productivity, demonstrating the potential for selfish genetic elements to move 9 sex ratios closer to the population-level optimum.
    [Show full text]
  • Cellular/Molecular Analysis of Interspecies Sterile Male Hybrids in Drosophila
    Western University Scholarship@Western Electronic Thesis and Dissertation Repository 6-15-2017 12:00 AM Cellular/Molecular Analysis of Interspecies Sterile Male Hybrids In Drosophila Rachelle L. Kanippayoor The Unviersity of Western Ontario Supervisor Dr Amanda Moehring The University of Western Ontario Graduate Program in Biology A thesis submitted in partial fulfillment of the equirr ements for the degree in Doctor of Philosophy © Rachelle L. Kanippayoor 2017 Follow this and additional works at: https://ir.lib.uwo.ca/etd Part of the Biodiversity Commons, Biology Commons, Cell Biology Commons, Evolution Commons, and the Molecular Genetics Commons Recommended Citation Kanippayoor, Rachelle L., "Cellular/Molecular Analysis of Interspecies Sterile Male Hybrids In Drosophila" (2017). Electronic Thesis and Dissertation Repository. 4647. https://ir.lib.uwo.ca/etd/4647 This Dissertation/Thesis is brought to you for free and open access by Scholarship@Western. It has been accepted for inclusion in Electronic Thesis and Dissertation Repository by an authorized administrator of Scholarship@Western. For more information, please contact [email protected]. Abstract Over time, genetic differences can accumulate between populations that are geographically separated. This genetic divergence can lead to the evolution of reproductive isolating mechanisms that reduce gene flow between the populations and, upon secondary contact, result in distinct species. The process of speciation is, thus, what accounts for the multitude of species that contribute to the rich biodiversity on Earth. Interspecies hybrid sterility is a postzygotic isolating mechanism that affects the development of hybrids, rendering them sterile. A notable trend, known as Haldane's rule, describes how heterogametic individual hybrids (e.g.
    [Show full text]