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The molecular basis of parallel evolutionary divergence by differential pollinator attraction

Titel Englisch The molecular basis of parallel evolutionary divergence by differential pollinator attraction
Gesuchsteller/in Schlüter Philipp M.
Nummer 155943
Förderungsinstrument Projektförderung (Abt. I-III)
Forschungseinrichtung Institut für Systematische Botanik und Botanischer Garten Universität Zürich
Hochschule Universität Zürich - ZH
Hauptdisziplin Molekularbiologie
Beginn/Ende 01.06.2015 - 31.05.2019
Bewilligter Betrag 459'516.00
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Alle Disziplinen (3)

Disziplin
Molekularbiologie
Oekologie
Botanik

Keywords (10)

ecological speciation; next-generation sequencing; reproductive isolation; molecular basis of adaptation; parallel evolution; sexually deceptive orchids; ecological genomics; pollination; barrier genes; candidate genes

Lay Summary (Deutsch)

Lead
Auf Organismen wirkende heterogene natürliche Selektion resultiert in Merkmalsunterschieden, die der umweltbedingten Adaptation dienen und letztlich mit der Entstehung neuer Arten einhergehen können. Dieses Projekt untersucht, inwieweit evolutionär wiederholte Adaptations-bedingte Artbildungs-Szenarien durch ähnliche genetische Veränderungen ermöglicht werden.
Lay summary

Ökologische Artbildung beschreibt die Entstehung neuer Arten unter umweltbedingtem, variierendem Selektionsdruck. Es ist nicht geklärt, ob gleicher divergenter Selektionsdruck stets in gleicher Weise zu Artdivergenz führt. Es stellt sich vor allem die Frage, ob wiederholte evolutionäre Bedingungen gleiche Adaptationen zur Folge haben, bzw. ob die gleichen molekularen Prozesse daran beteiligt sind. Durch die Untersuchung dieser Fragestellung anhand von mediterranen sexualtäuschenden Orchideen der Gattung Ophrys befasst sich dieses Projekt mit einer grundsätzlichen Frage zur Reproduzierbarkeit und Vorhersagbarkeit der Evolution.

Ragwurz-Arten (Ophrys) imitieren die Sexualsignale weiblicher Insekten, sodass männliche Partner zur Bestäubung angelockt werden. Die Solitärbiene Andrena repräsentiert eine häufige Gattung an bestäubenden Insekten. Die chemischen Signale, mit denen Ophrys-Arten diese Bienen hochspezifisch anlocken, sind verhältnismäßig gut bekannt. Veränderungen in den Bestäuber-anlockenden Signalen gehen mit einer Änderung in der Bestäuberspezies und einer raschen Entwicklung neuer Orchideenarten einher. In einigen nicht-nahverwandten Ophrys-Artgruppen führen Wechsel zwischen denselben Bestäuber-Arten zu paralleler Artbildung in den Ophrys-Orchideen.

Das aktuelle Projekt beleuchtet zwei parallele Fälle von ökologischer Artbildung aufgrund von Anpassung an die beiden gleichen Andrena-Bestäuberarten. Dieses Projekt wird die Ökologie, die phänotypischen Merkmale und Adaptationsprozesse, sowie die genomischen und genetischen Veränderungen während der Art-Divergenz vergleichen. Nach Möglichkeit werden spezifische Gene oder Mutationen, die wiederholt eine Rolle in der Artbildung spielen, genau auf molekularer Ebene charakterisiert werden. Dadurch kann dieses Projekt Einblicke in das Ausmaß der Wiederholbarkeit der an Artbildung involvierter Mechanismen liefern.

Direktlink auf Lay Summary Letzte Aktualisierung: 30.03.2015

Lay Summary (Englisch)

Lead
Heterogeneous natural selection acting on organisms can result in differences in traits that serve as adaptations to the environment, and ultimately the origin of novel species. This project asks if genetic changes proceed via similar mechanisms in replicated evolutionary scenarios.
Lay summary

Ecological speciation is the process by which novel species originate due to differing selection pressures by the environment. It is unclear if the same selection pressures would always lead to species divergence in the same fashion. In particular, are the same adaptations observed under replicated evolutionary conditions, and if so, are the same molecular mechanisms involved in producing them? By addressing this question, this project targets a fundamental question about the repeatability and predictability of evolution. To do so, it utilises Mediterranean sexually deceptive Ophrys orchids. These orchids imitate the sexual signals of female insects to attract male insects for pollination. As a result, they tend to be pollinated only by a single species of pollinator and, upon change of pollinator-attractive signals, can quickly evolve new orchid species associated with a new pollinating insect. One common genus of pollinating insects is the solitary bee Andrena; here, the chemical details of the pollinator-attractive signals are relatively well known. In several unrelated Ophrys species groups, the same pollinators have likely driven divergence of species in parallel. The present project will compare two parallel cases of ecological speciation linked to the same two Andrena pollinator species, to understand to what extent speciation and adaptation occurred convergently. This will involve comparison of the ecology, the phenotypic traits and adaptations, and the genomic and genetic changes that happened during divergence. Moreover, we will compare key genes and mutations involved in repeated adaptations to pollinators. Overall, this project will yield insight into the extent to which the same mechanisms repeatedly underlie biological adaptations to the same selective agents. This project thus has the potential to reveal generalities in evolutionary patterns and processes and will allow us to take a step towards understanding the repeatability of evolutionary change.


Direktlink auf Lay Summary Letzte Aktualisierung: 30.03.2015

Verantw. Gesuchsteller/in und weitere Gesuchstellende

Mitarbeitende

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130796 The molecular basis of floral traits underlying reproductive isolation in sexually deceptive orchids 01.11.2010 Projektförderung (Abt. I-III)
130796 The molecular basis of floral traits underlying reproductive isolation in sexually deceptive orchids 01.11.2010 Projektförderung (Abt. I-III)
171682 PSC Creative Camps for Youth 01.04.2017 Agora

Abstract

Sexually deceptive orchids of the genus Ophrys use chemical mimicry of their pollinators’ sex pheromones to attain highly specific pollination. This is associated with strong pollinator-mediated reproductive isolation that can drive species divergence by ecological speciation. Within the genus, parallel species radiations have taken place. Here, distantly related species groups convergently use the same pollinators, resulting in parallel cases of mimicry, while the same pollinators drive divergence between species within each group. Building upon previous SNSF-funded research, but setting it in the context of a repeated evolutionary scenario, this project seeks to understand the extent of similarities (1) in the genomic architecture, and (2) in the molecular mechanisms underlying adaptive, pollinator-attractive traits responsible for reproductive isolation in two parallel cases of pollinator-driven species divergence. This will be done by combining field and phenotypic work, pollination biology, ecological genomics and molecular biology approaches in an evolutionary framework. Specifically, two PhD students will address these questions:• 1a: What is the extent of convergence in pollinator-attractive traits and reproductive barriers?• 1b: What is the extent of convergence in the genetic/genomic architecture of these traits?• 1c: Which factors constrain or facilitate the evolution of metabolic pathways controlling pollination? • 2a: What is the biochemical function of key mutations underlying repeated adaptation to pollinators?• 2b: What are the evolutionary origin and ecological effect of important convergent adaptive mutations?• 2c: Which genetic factors regulate or modify the effect of important adaptive genes?To investigate these questions, one student will focus on genome-scale patterns using RNA-Seq and Exome-Seq in natural plant populations, linking these genomic data with pollinator-attractive phenotypic traits (1a-c). The second student will focus on the detailed molecular mechanisms of selected genes and mutations therein, which are of particular relevance to specific pollinator attraction (2a-c). By studying the molecular basis of parallel pollinator-mediated ecological speciation, research results from this project will be relevant to our general understanding of adaptation, plant speciation and diversity, the pace at which reproductive barriers can arise, and the factors that contribute to enable or prevent evolutionary change. In particular, by comparison among evolutionary replicates, this research will be informative of the extent to which the same mechanisms repeatedly underlie biological adaptations to the same selective agents; it thus has the potential to reveal generalities in evolutionary patterns and processes.
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