Effects of selection and drift on G matrix evolution in a heterogeneous environment: a multivariate Qst-Fst Test with the freshwater snail Galba truncatula.

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Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Effects of selection and drift on G matrix evolution in a heterogeneous environment: a multivariate Qst-Fst Test with the freshwater snail Galba truncatula.
Journal
Genetics
Author(s)
Chapuis E., Martin G., Goudet J.
ISSN
0016-6731
Publication state
Published
Issued date
2008
Peer-reviewed
Oui
Volume
180
Number
4
Pages
2151-2161
Language
english
Abstract
Unraveling the effect of selection vs. drift on the evolution of quantitative traits is commonly achieved by one of two methods. Either one contrasts population differentiation estimates for genetic markers and quantitative traits (the Q(st)-F(st) contrast) or multivariate methods are used to study the covariance between sets of traits. In particular, many studies have focused on the genetic variance-covariance matrix (the G matrix). However, both drift and selection can cause changes in G. To understand their joint effects, we recently combined the two methods into a single test (accompanying article by Martin et al.), which we apply here to a network of 16 natural populations of the freshwater snail Galba truncatula. Using this new neutrality test, extended to hierarchical population structures, we studied the multivariate equivalent of the Q(st)-F(st) contrast for several life-history traits of G. truncatula. We found strong evidence of selection acting on multivariate phenotypes. Selection was homogeneous among populations within each habitat and heterogeneous between habitats. We found that the G matrices were relatively stable within each habitat, with proportionality between the among-populations (D) and the within-populations (G) covariance matrices. The effect of habitat heterogeneity is to break this proportionality because of selection for habitat-dependent optima. Individual-based simulations mimicking our empirical system confirmed that these patterns are expected under the selective regime inferred. We show that homogenizing selection can mimic some effect of drift on the G matrix (G and D almost proportional), but that incorporating information from molecular markers (multivariate Q(st)-F(st)) allows disentangling the two effects.
Keywords
Animals, Computer Simulation, Environment, Evolution, Molecular, Fresh Water, Genetic Drift, Genetics, Population/methods, Phenotype, Quantitative Trait, Heritable, Selection (Genetics), Snails/genetics
Pubmed
Web of science
Open Access
Yes
Create date
09/01/2009 14:21
Last modification date
20/08/2019 12:24
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