Projekt

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The expression, selection and evolution of combined versus separate sexes in an annual plant

Gesuchsteller/in Pannell John Richard
Nummer 141052
Förderungsinstrument Projektförderung (Abt. I-III)
Forschungseinrichtung Département d'Ecologie et d'Evolution Faculté de Biologie et de Médecine Université de Lausanne
Hochschule Universität Lausanne - LA
Hauptdisziplin Botanik
Beginn/Ende 01.11.2012 - 29.02.2016
Bewilligter Betrag 624'000.00
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Alle Disziplinen (3)

Disziplin
Botanik
Oekologie
Genetik

Keywords (11)

Population genetics; Life history; Sexual system; Competition; Experimental evolution; Sex determination; Sex allocation; Natural selection; Hermaphroditism; Dioecy; Pollen dispersal

Lay Summary (Englisch)

Lead
Lay summary

Plants present a startling array of sexual systems that directly regulate how genes are transmitted to the next generation. Most flowering plants are hermaphrodites, but separate sexes have evolved frequently. Why? Hypotheses fall broadly into two classes. The first idea, which has been studied a great deal, is that separate sexes evolve principally to avoid the detrimental costs of self-fertilisation. The second idea, which has been much less studied, is that separate sexes evolve in response to selection for sexual specialisation, e.g., because of advantages of specialised inflorescences, morphology, physiology, etc., for males vs. females. In this project, we will address several questions mainly relevant to this second, sexual specialisation, hypothesis: What are the benefits of sexual specialisation in terms of size and structure of inflorescences? How do specialised inflorescences evolve, and how do genes responsible for variation in the inflorescence vary within a species? How does natural selection for sexual specialisation operate when individuals compete for both mates and limited resources? How does sexual specialisation affect susceptibility to herbivory, and how does sex-differential herbivory in turn affect fitness? When separate sexes do evolve, how is their sex determined, and are the same (genetic) mechanisms re-adopted when separate sexes are lost and then regained? What selective factors are responsible for the breakdown of separate sexes back towards hermaphroditism? Finally, how should hermaphrodites divide their resources between male and female functions? To answer these questions, we will study morphological and genomic variation and undertake experiments using the remarkable variation shown by the wind-pollinated plant Mercurialis annua. The project builds on more than a decade of intensive study of M. annua by using both experimental evolution and genomic sequencing to understand how and why transitions occur between combined and separate sexes in plants. 

Direktlink auf Lay Summary Letzte Aktualisierung: 21.02.2013

Verantw. Gesuchsteller/in und weitere Gesuchstellende

Mitarbeitende

Publikationen

Publikation
A test of the size-constraint hypothesis for a limit to sexual dimorphism in plants
Labouche Anne-Marie, Pannell John (2016), A test of the size-constraint hypothesis for a limit to sexual dimorphism in plants, in Oecologia, 181, 873-884.
Long story short
Pannell John, Cossard Guillaume (2016), Long story short, in eLife, 5, e20314.
Inferring the mode of origin of polyploid species from next-generation sequence data
Roux Camille, Pannell John (2015), Inferring the mode of origin of polyploid species from next-generation sequence data, in Molecular Ecology, 24, 1047-1059.
A quantitative genetic signature of senescence in a short-lived perennial plant.
Pujol Benoit, Marrot P., Pannell John R. (2014), A quantitative genetic signature of senescence in a short-lived perennial plant., in Current Biology, 24, 744-747.
Evolución de la agregación y separación de sexos: ¿Qué hemos aprendido de las poblaciones ibéricas de Mercurialis annua?
Pannell John, Santos-del-Blanco Luis (2014), Evolución de la agregación y separación de sexos: ¿Qué hemos aprendido de las poblaciones ibéricas de Mercurialis annua?, in Ecosistemas , 23, 13-22.
Plasticity in sex allocation in the plant Mercurialis annua is greater for hermaphrodites sampled from dimorphic than from monomorphic populations
Sanchez-Vilas J., Pannell John R. (2014), Plasticity in sex allocation in the plant Mercurialis annua is greater for hermaphrodites sampled from dimorphic than from monomorphic populations, in Journal of Evolutionary Biology, 27, 1939-1947.
Regional variation in sex ratios and sex allocation in androdioecious Mercurialis annua
Pannell John R., Eppley S.M., Dorken M.E., Berjano R. (2014), Regional variation in sex ratios and sex allocation in androdioecious Mercurialis annua, in Journal of Evolutionary Biology, 27, 1467-1477.
Evolution in subdivided plant populations: concepts, recent advances and future directions
Pannell John R., Fields Peter D. (2013), Evolution in subdivided plant populations: concepts, recent advances and future directions, in New Phytologist, 201, 417-432.
The incidence and selection of multiple mating in plants
Pannell John R., Labouche Anne-Marie (2013), The incidence and selection of multiple mating in plants, in Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences, 368, 20120051.
Effects of pollination intensity on offspring number and quality in a wind-pollinated herb
Labouche Anne-Marie, Richards Shane, Pannell John, Effects of pollination intensity on offspring number and quality in a wind-pollinated herb, in Journal of Ecology.

Zusammenarbeit

Gruppe / Person Land
Formen der Zusammenarbeit
Gerhard Prenner, Kew Gardens Grossbritannien und Nordirland (Europa)
- vertiefter/weiterführender Austausch von Ansätzen, Methoden oder Resultaten
Dmitry Filatov, Department of Plant Sciences, University of Oxford Grossbritannien und Nordirland (Europa)
- vertiefter/weiterführender Austausch von Ansätzen, Methoden oder Resultaten
- Publikation
Gabriel Marais, CNRS, Lyon Frankreich (Europa)
- vertiefter/weiterführender Austausch von Ansätzen, Methoden oder Resultaten
- Publikation
Patrice David, CNRS, Montpellier Frankreich (Europa)
- vertiefter/weiterführender Austausch von Ansätzen, Methoden oder Resultaten
- Publikation
Shane Richards, CSIRO, Hobart, Australia Australien (Ozeanien)
- vertiefter/weiterführender Austausch von Ansätzen, Methoden oder Resultaten
- Publikation
Sergio Rasmann, University of Lausanne Schweiz (Europa)
- vertiefter/weiterführender Austausch von Ansätzen, Methoden oder Resultaten
- Publikation

Wissenschaftliche Veranstaltungen

Aktiver Beitrag

Titel Art des Beitrags Titel des Artikels oder Beitrages Datum Ort Beteiligte Personen
Population Genetics Group Vortrag im Rahmen einer Tagung Temporal dynamics of sexual dimorphism in an annual plant 14.12.2015 Edinburgh, Grossbritannien und Nordirland Cossard Guillaume;
European Society of Evolutionary Biology Vortrag im Rahmen einer Tagung Bottom-up effects of local selection for outcross siring success shape population genetic structure at the regional level 13.08.2015 Lausanne, Schweiz Santos del Blanco Luis; Pannell John Richard;
European Society of Evolutionary Biology Poster Temporal dynamics of sexual dimorphism in an annual plant 13.08.2015 Lausanne, Schweiz Pannell John Richard; Cossard Guillaume;
SwissPlants conference Vortrag im Rahmen einer Tagung Evolution of the mating system in metapopulations and range expansions 28.01.2015 Leukabad, Schweiz Pannell John Richard;
BES symposium on Plant Mating Systems Vortrag im Rahmen einer Tagung Mating-system evolution at range margins 15.12.2014 Lille, Frankreich Pannell John Richard;
British Ecological Society Meeting Vortrag im Rahmen einer Tagung Sex specific selection for nocturnal vesus diurnal pollination in a plant- pollinator/seed predator system 10.12.2014 Lille, Frankreich Labouche Anne-Marie;
The Genetics of Colonizing Species Vortrag im Rahmen einer Tagung Evolution of the mating system in colonising species 06.08.2014 Asilomar, California, Vereinigte Staaten von Amerika Pannell John Richard;
Society for the Study of Evolution, USA Vortrag im Rahmen einer Tagung Joint effects of pollen limitation and pollen competition on offspring quality in a wind-pollinated herb 01.06.2014 Raleigh, Vereinigte Staaten von Amerika Labouche Anne-Marie;
Ecoflor Vortrag im Rahmen einer Tagung Sex, asex and the loss of hermaphroditism – or a homage to males 01.02.2014 Cadiz, Spanien Pannell John Richard;
PopGroup conference Vortrag im Rahmen einer Tagung Sex determination in Mercurialis, a plant genus with diverse sexual systems 06.01.2014 Bath, Grossbritannien und Nordirland Pannell John Richard;
European Society for Evolutionary Biology Vortrag im Rahmen einer Tagung Inflorescence architecture and siring success in a wind-pollinated plant: a case for good and bad design 01.08.2013 Lisbon, Portugal Santos del Blanco Luis; Pannell John Richard;
Jaque Monod conference on sex and sexual systems Vortrag im Rahmen einer Tagung olutionary transitions between combined and separate sexes in plants 22.05.2013 Roscoff, Frankreich Pannell John Richard;


Selber organisiert

Titel Datum Ort
European Society of Evolutionary Biology 13.08.2015 Lausanne, Schweiz
SwissPlants conference 28.01.2015 Leukabad, Schweiz

Veranstaltungen zum Wissenstransfer

Aktiver Beitrag

Titel Art des Beitrags Titel des Artikels oder Beitrages Datum Ort Beteiligte Personen
Mystères de l'Unil Performances, Ausstellungen (z.B. für Bildungsinstitute) 01.06.2016 University of Lausanne, Schweiz


Selber organisiert

Titel Datum Ort
De A à Sexe(s) - exhibition at the Musée de zoologie and Jardin botanique, Lausanne 17.05.2014 Lausanne, Schweiz

Kommunikation mit der Öffentlichkeit

Kommunikation Titel Medien Ort Jahr
Referate/Veranstaltungen/Ausstellungen Société vaudoise des sciences naturelles Westschweiz 2015

Verbundene Projekte

Nummer Titel Start Förderungsinstrument
163384 The expression, selection and evolution of combined versus separate sexes in an annual plant 01.03.2016 Projektförderung (Abt. I-III)
147625 The evolutionary genomics of recombining sex chromosomes 01.04.2014 Sinergia
163384 The expression, selection and evolution of combined versus separate sexes in an annual plant 01.03.2016 Projektförderung (Abt. I-III)

Abstract

Most flowering plants are hermaphrodites, but evolutionary transitions between hermaphroditism and dioecy (combined and separate sexes, respectively) have been frequent. What forces drive transitions from hermaphroditism to dioecy has been the focus of a great deal of theorising. Hypotheses fall broadly into two classes: the ‘inbreeding avoidance hypothesis’ that dioecy evolves as an outcrossing mechanism, principally to avoid the detrimental costs of self-fertilisation; and the ‘sexual specialisation hypothesis’ that dioecy evolves in response to selection for specialisation in the allocation of resources to male vs. female functions, e.g., because of advantages of specialised inflorescences, morphology, physiology, etc., for males vs. females. Of these two hypotheses, the first has received more empirical attention than the second, probably because it is not easy to measure the direct and indirect fitness benefits of being a gender specialist vs. generalist, particularly for male function. In this project, we propose to use a system that has been developed as an outstanding model for the study of plant sex allocation (reproductive investment into male vs. female functions) and sexual-system transitions to address several questions mainly relevant to the sexual specialisation hypothesis: What are the fitness benefits of sexual specialisation, particularly in terms of size and inflorescence architecture? How do specialised inflorescences evolve within a genus, what is the genetic architecture of inflorescence variation within a species, and how does this affect fitness? How does selection for sexual specialisation operate in a context in which individuals compete for both mates and limited resources, particularly when individuals competing with one another for resources share common evolutionary interests in terms of co-parentage? How does sexual specialisation in sex allocation affect herbivory, and how does sex-differential herbivory in turn affect fitness? When separate sexes do evolve, how is their sex determined, and are the same (genetic) mechanisms re-adopted when separate sexes are lost and then regained? In cases where the local environment affects sex expression, what environmental cues are used. When the separation of the sexes breaks down, such that hermaphroditism evolves from dioecy, what selective factors are responsible? In particular, is there any direct evidence that selection for reproductive assurance can lead to the evolution of hermaphroditism from dioecy? Finally, what factors influence the expression and evolution of hermaphroditic sex allocation, i.e., the division of resources between male and female functions? We propose to address these questions using a combination of comparative (morphological and genomic) and experimental approaches (experimental evolution and mating-system manipulation) using the clade of wind-pollinated annual species in the genus Mercurialis (Euphorbiaceae), which shows remarkable variation in the distribution of gender and sex allocation among species and populations within species. A particularly novel aspect of our application is the plan to use natural selection in situations where the context of competition for mates and/or resources has been manipulated to expose the factors responsible for phenotypic evolution of sex allocation and sexual system. Another novel aspect is the proposal to use high throughput sequencing to uncover new sex-linked markers in dioecious species, and to trace these sex-linked markers through a clade in which separate sexes have come and gone more than once. The project builds on more than a decade of intensive study of one of the species in the annual Mercurialis clade, M. annua, for which a great deal is now known about the species’ phylogenetic and phylogeographic histories, the genetic architecture of sex allocation (including responsiveness to artificial and natural selection), natural patterns of sex allocation at a wide range of spatial scales, and the expression of gender and sexual dimorphism under various environmental conditions. Diploid-acting microsatellites have recently been developed for M. annua using a novel approach that overcomes the difficulties of polyploidy, and both a reference transcriptome and the genome of diploid M. annua have just been sequenced. This previous work places us in a strong position to address the important questions outlined above using novel approaches in a well-characterised ecological genetic model.
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