Salazar Jaramillo, Laura

English

Parasieten vormen een sterke selectiekracht in de natuur en organismen evolueren mechanismen om zich daartegen te verdedigen. De vragen die centraal staan in dit proefschrift hebben betrekking op hoe deze mechanismen evolueren, hoe ze gecodeerd zijn in het genoom en hoe ze gedurende het evolutionaire proces kunnen verdwijnen. Mijn onderzoek richtte zich op het verdedigingsmechanisme dat Drosophila fruitvliegen bezitten om een aanval van parasitaire sluipwespen te overleven. Deze sluipwespen leggen hun eieren in de larven van de fruitvliegen, en voeden zich hiermee gedurende hun ontwikkeling. Dit leidt tot de dood van de gastheer, tenzij deze zich met een immuunreactie, genaamd gemelaniseerde inkapseling, kan verdedigen. Er zijn grote verschillen tussen Drosophila populaties en Drosophila soorten in hoe goed ze zich kunnen verdedigen tegen een aanval van de parasitaire sluipwesp, waarbij sommige soorten helemaal geen resistentie vertonen. Mijn onderzoek geeft aan dat dit mechanisme recent is geëvolueerd, in dezelfde subgroep van het Drosophila geslacht als waarin D. melanogaster voorkomt. De evolutie van dit mechanisme is geassocieerd met verkrijgen van nieuwe genen en van een nieuw type bloedcel. Sommige van deze genen laten ook grote variatie zien tussen populaties van D. melanogaster. Binnen de groep van soorten die in staat is zich te verdedigen tegen de sluipwesp, heeft D. sechellia het vermogen om zich te verweren verloren. Dit is een endemische soort, alleen voorkomend op een specifieke eilandengroep, en gespecialiseerd op de noni fruit die giftig kan zijn voor andere insecten. Mijn experimenten en veldonderzoek lieten zien dat er op noni een verminderd risico bestaat om aangevallen te worden door een sluip-wesp. In conclusie, door evolutionaire genomica te combineren met ecologische informatie, hebben wij de componenten kunnen karakteriseren die het voor sommige Drosophila soorten mogelijk maakt om zich succesvol verweren tegen een anderszins dodelijke aanval van een sluip-wesp. Bovendien hebben we kunnen laten zien hoe deze immuunreactie gemoduleerd is tussen verschillende populaties en verschillende soorten, en hoe deze reactie verloren is gegaan in een specifieke ecologische omgeving.Parasites constitute a strong selective force in nature, and organisms evolve defence mechanisms to cope with them. The central questions of this thesis are how these mechanisms evolve and are encoded in the genome, and how they can be lost during evolution. My research focused on an immune response called melanotic encapsulation, which is used by Drosophila fruitflies to survive attacks by parasitoid wasps that lay their eggs in the fruitfly larvae. Drosophila species and populations vary largely in how successful they are in surviving parasitoid attack, with some species completely lacking the ability to resist. My research indicates that this defence mechanism evolved recently in a subgroup of Drosophila species that contains D. melanogaster. Its evolution is associated with the acquisition of new genes and a new type of blood cells. Comparisons among Drosophila species and populations of D. melanogaster revealed considerable variation in the expression of some of these genes. Inside the group of species able to resist, the encapsulation ability was lost in the endemic island species D. sechellia that specialized on a fruit that can be toxic to other insects. My experiments and field study showed a reduced risk of parasitoid attack in these fruits. In conclusion, by combining evolutionary genomics with ecological information, I characterized the components that enable some Drosophila species to mount a successful immune response to a lethal parasitoid infection, how this response is modulated among populations of one species and how it was lost in a particular ecological settin

ARTS repository - University of Groningen

   University of GroningenEvolutionary genomics of the immune response against parasitoids in DrosophilaSalazar Jaramillo, LauraIMPORTANT NOTE: You are advised to consult the publisher's version (publisher's PDF) if you wish to cite fromit. Please check the document version below.Document VersionPublisher's PDF, also known as Version of recordPublication date:2014Link to publication in University of Groningen/UMCG research databaseCitation for published version (APA):Salazar Jaramillo, L. (2014). Evolutionary genomics of the immune response against parasitoids inDrosophila. [S.n.].CopyrightOther than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of theauthor(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons).The publication may also be distributed here under the terms of Article 25fa of the Dutch Copyright Act, indicated by the “Taverne” license.More information can be found on the University of Groningen website: https://www.rug.nl/library/open-access/self-archiving-pure/taverne-amendment.Take-down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediatelyand investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons thenumber of authors shown on this cover page is limited to 10 maximum.Download date: 07-06-2022Evolutionary genomics of the immune response against parasitoids in Drosophila byLaura Salazar Jaramillo1) The parasitoid resistance mechanism of melanotic encapsulation found in D. melanogaster evolved in a subgroup of Drosophila species and involves duplicated genes, as well as the differentiation of hemocytes into a new type of blood cell (This thesis, Chapter 2)2) Within-species variation in resistance against parasitoids results from the modulation of the immune response by changing the number of circulating hemocytes and the differential expression of transcript isoforms.  (This thesis, Chapter 3 and Chapter 4).3) The specialization of Drosophila sechellia on noni fruit may have protected it from attack by parasitoid wasps, resulting in the loss of its ability to encapsulate parasitoid eggs (This thesis, Chapter 5).4) Working with a model organism can be both a blessing and a curse: a broad range of tools are available for functional characterization, but this also increases the burden of proof.5) Redundancy creates evolutionary innovations, while natural selection merely modifies (Susumu Ohno, 19701). Accordingly, knock-down functionality can mostly assess essentiality, while functional redundancy may be more fundamental for evolvability6) Masterpieces are not single solitary births; they are the outcome of many years of thinking in common, of thinking by the body of the people, so the experience of the mass is behind the single voice (Virginia Woolf2)7) Science is not a heartless pursuit of objective information; it is a creative human activity its geniuses acting more as artists than as information processors (Stephen Jay Gould3)8) The best way for scientists to contribute to the public interest is by ensuring that their work is freely available for any purpose in any place of the world. 1 Susumu Ohno (1970). Evolution by gene duplication. Springer-Verlag2 Virgina Woolf (1989). A room of one's own. Harcourt Brace & Co.3 Stephen Jay Gould (1979). Ever since Darwin: Reflections in Natural History. W. W. Norton & Company 

Evolutionary genomics of the immune response against parasitoids in <i>Drosophila</i>

https://pure.rug.nl/ws/files/15050376/Propositions.pdf

Evolutionary genomics of the immune response against parasitoids in <i>Drosophila</i>

Abstract

Similar works

Full text

Available Versions

ARTS repository - University of Groningen