Projekt

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Genetic determinants of adaptive variation and their evolution in structured populations

Gesuchsteller/in Guillaume Frédéric
Nummer 121697
Förderungsinstrument Ambizione
Forschungseinrichtung Institut für Integrative Biologie Departement Umweltwissenschaften ETHZ
Hochschule ETH Zürich - ETHZ
Hauptdisziplin Genetik
Beginn/Ende 01.08.2009 - 31.07.2012
Bewilligter Betrag 420'707.00
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Keywords (10)

G-matrix; pleiotropy; modularity; evolution; natural selection; gene flow; genotype-phenotype map; local adaptation; quantitative character; modeling

Lay Summary (Englisch)

Lead
Lay summary
The genetic architecture of complex phenotypic traits (e.g. morphological) is thought to deeply influence their evolution. This project seeks to characterize and understand the evolutionary implications of the pleiotropic nature of the genes involved in adaptations to environmental variation as found in natural populations.
Evolutionary quantitative genetics treats the genetic architecture of phenotypic traits in an abstract way that ignores the genetic details of such traits. In the context of multivariate evolution, the tool that bridges the gap between the genotypes and the phenotypes of correlated traits is the G-matrix, the matrix of genetic variance-covariances that encapsulates the structure of heritable genetic variation of a population and helps predict its short term evolution. However, adaptive phenotypic changes are primarily caused by selective changes in allele frequencies at the genes underlying the evolving traits. These allelic changes not only depend on the genetic variation for the traits but also on the existence of genetic constraints, as caused by the pleiotropic interactions of the genes. Those changes will also affect the evolution of the G-matrix itself by causing changes in genetic variation in the population. Therefore, in oder to understand the evolutionary properties of a population, we have to understand how the genetic architecture of a set of traits interacts with the different evolutionary forces that prevail in natural populations.
This project proposes to open the black box and look at the role the precise genetic architecture of the traits plays in predicting their evolution. Properties of the G-matrix will be studied in the context of spatially subdivided populations because allele frequency changes also strongly depend on drift and gene flow. Pleiotropy and modularity will be the two main features of the genotype-phenotype map that will be studied.
Ample empirical evidence points to the widespread variation of the pleiotropic and epistatic nature of the genes involved in the makeup of phenotypic traits whereas theory is mostly concerned with simple, uniformly additive genetic architectures. In order to have a more comprehensive picture of the process of evolution by natural selection, we have to incorporate these genetic details into our theoretical description of the process. This project will seek to, first, unravel the evolutionary significance of variation in pleiotropy of the genotype-phenotype (i.e. its modularity) map using available genomic data and, second, understand the evolution of pleiotropy itself using a modeling approach.
Direktlink auf Lay Summary Letzte Aktualisierung: 21.02.2013

Verantw. Gesuchsteller/in und weitere Gesuchstellende

Mitarbeitende

Publikationen

Publikation
Epistasis and pleiotropy affect the modularity of the genotype-phenotype map of cross-resistance in HIV-1
Polster Robert and Petropoulos Christos J. and Bonhoeffer Sebastian and Guillaume Frédéric (2016), Epistasis and pleiotropy affect the modularity of the genotype-phenotype map of cross-resistance in HIV-1, in Molecular Biology and Evolution, 33(12), 3213-3225.
Long-distance gene flow and adaptation of forest trees to rapid climate changes
Kremer A., Ronce O., Robledo-Arnuncio J.J., Guillaume F., Bohrer G., Nathan R., Bridle J.R., Gomulkiewicz R., Klein E., Ritland K., Kuparinen A., Gerber S., Schueler S. (2012), Long-distance gene flow and adaptation of forest trees to rapid climate changes, in Ecology Letters, 15(4), 378-392.
The dynamics of mitochondrial mutations causing male infertility in spatially structured populations
Zhang H., Guillaume F., Engelstädter J. (2012), The dynamics of mitochondrial mutations causing male infertility in spatially structured populations, in Evolution, 0, 0-0.
Migration-induced phenotypic divergence: the migration-selection balance of correlated traits
Guillaume Frédéric (2011), Migration-induced phenotypic divergence: the migration-selection balance of correlated traits, in Evolution, 65(6), 1723-1738.
Predicting adaptation under migration load: the role of genetic skew
Yeaman Sam, Guillaume Frédéric (2009), Predicting adaptation under migration load: the role of genetic skew, in Evolution, 63(11), 2926-2938.
Testing for spatially divergent selection: comparing QST to FST
Whitlock Michael C., Guillaume Frederic (2009), Testing for spatially divergent selection: comparing QST to FST, in Genetics, 183(3), 1055-1063.

Wissenschaftliche Veranstaltungen

Aktiver Beitrag

Titel Art des Beitrags Titel des Artikels oder Beitrages Datum Ort Beteiligte Personen
Evolution 2012 - Joint congress, ESEB, CSEE, SSE Vortrag im Rahmen einer Tagung Genetic constraints and the evolution of a species’ range in multivariate trait space 06.07.2012 Ottawa, Canada, Kanada Guillaume Frédéric;
ESEB - 13th congress of the European Society of Evolutionary Biology Vortrag im Rahmen einer Tagung GENE FUNCTIONAL TRADE-OFFS AND THE EVOLUTION OF PLEIOTROPY 20.08.2011 Tübingen, De, Deutschland Guillaume Frédéric;
Evolutionary and ecological genomics of adaptation Vortrag im Rahmen einer Tagung Migration–induced phenotypic divergence: The migration–selection balance of correlated traits 02.09.2010 Fribourg, Schweiz Guillaume Frédéric;
Evolution 2010 Vortrag im Rahmen einer Tagung Migration-induced phenotypic divergence: The migration-selection balance of correlated traits 23.06.2010 Portland, Oregon, USA, Vereinigte Staaten von Amerika Guillaume Frédéric;


Verbundene Projekte

Nummer Titel Start Förderungsinstrument
141987 Genetic determinants of adaptive variation and their evolution in structured populations 01.08.2012 Ambizione

Abstract

In this project, I am asking the question of how does the genetic architecture of complex traits affect their evolution in the context of adaptive evolution in structured populations. The genetic architecture of a trait can be understood as the amount of genetic variance available for that trait to evolve, or its heritability, and the way it co-varies with the other traits that determine the complex set of phenotypic characters upon which selection acts. The genetic variances and covariances of the traits under study in a population are generally summarized by a matrix, the genetic variance-covariance matrix or G-matrix. The multivariate response to selection of a population is given by the product of G and ß, the selection gradient (Lande 1979). Therefore, the main effect of the existence of genetic covariances between the traits is to divert the evolution of the population from its optimal path toward its phenotypic optimum, represented by ß. This project proposes to study the joint effects of the genetic architecture of quantitative traits and population structure on the evolution of the G-matrix. Both are predicted to deeply influence the evolution of the structure of the G-matrix because the variation in genetic variances and covariances of the traits has its source in allelic frequencies variations due both to the effect of population structure on evolutionary processes and to the variation in the pleiotropic effects of the genes coding for the traits. G thus summarizes both effects and helps predict their joint influence on the adaptive evolution of species.I will further seek to model the genetic architecture of phenotypic characters based on the information we have from model organisms (e.g. yeast, mouse, or stickleback) on the precise genetic basis of such traits. The genetic properties I will search for in these empirical datasets are the distribution of pleiotropic effects and the extent of modularity of the genotype-phenotype map (the g-p map). Modularity represents how the pleiotropic effects of the genes cluster together to affect only a subset of traits. Modular traits are thus thought to be able to independently respond to selection whereas integrated traits are more constrained. Higher modularity is predicted to increase the rate of adaptation under certain circumstances. I will thus test whether modularity is correlated with the rate of evolution of the genes in the datasets available. I will develop a way to characterise that modularity of the g-p map, and, by integrating this real-world information into the simulation model, I will investigate the effects of the precise structure of the g-p map on the structure of the G-matrix and on adaptive evolution in structured populations.Finally, I will ask the question of how does the genetic architecture of complex traits evolve, or how does modularity of the g-p map emerge as a result of adaptive evolution of complex phenotypic traits? Very little is known about the selective pressures acting on the pleiotropy of the genes underlying complex phenotypes. I will thus develop a model of the evolution of pleiotropy that allows me to predict the distribution of pleiotropic effects as well as understand the selective pressures acting on the evolution of pleiotropy. Such an approach is awaited as it may lead to testable predictions such as what ecological opportunities are needed to favour the evolution of a modular structure in the genetic architecture of the phenotype. This project will thus be an attempt to fill a gap in our knowledge of the evolution of the genetic architecture of quantitative traits and to show how emergent properties of complex phenotypes, such as robustness (canalization), and evolvability, may evolve. The approach chosen will be a combination of individual-based and genetically explicit computer simulations, domain where I have most experience, and statistical analyses for the development of comparative and descriptive tools for the study of the G-matrix and the modularity of the genotype-phenotype map.
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