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Agrebi R.,Aix - Marseille University | Wartel M.,Aix - Marseille University | Brochier-Armanet C.,CNRS Biometry and Evolutionary Biology Laboratory | Mignot T.,Aix - Marseille University
Nature Reviews Microbiology | Year: 2015

Studying the evolution of macromolecular assemblies is important to improve our understanding of how complex cellular structures evolved, and to identify the functional building blocks that are involved. Recent studies suggest that the macromolecular complexes that are involved in two distinct processes in Myxococcus xanthus-surface motility and sporulation-are derived from an ancestral polysaccharide capsule assembly system. In this Opinion article, we argue that the available data suggest that the motility machinery evolved from this capsule assembly system following a gene duplication event, a change in carbohydrate polymer specificity and the acquisition of additional proteins by the motility complex, all of which are key features that distinguish the motility and sporulation systems. Furthermore, the presence of intermediates of these systems in bacterial genomes suggests a testable evolutionary model for their emergence and spread. © 2015 Macmillan Publishers Limited. All rights reserved.

Gouy M.,CNRS Biometry and Evolutionary Biology Laboratory | Guindon S.,CNRS Montpellier Laboratory of Informatics, Robotics and Microelectronics | Guindon S.,University of Auckland | Gascuel O.,CNRS Montpellier Laboratory of Informatics, Robotics and Microelectronics
Molecular Biology and Evolution | Year: 2010

We present SeaView version 4, a multiplatform program designed to facilitate multiple alignment and phylogenetic tree building from molecular sequence data through the use of a graphical user interface. SeaView version 4 combines all the functions of the widely used programs SeaView (in its previous versions) and Phylo-win, and expands them by adding network access to sequence databases, alignment with arbitrary algorithm, maximum-likelihood tree building with PhyML, and display, printing, and copy-to-clipboard of rooted or unrooted, binary or multifurcating phylogenetic trees. In relation to the wide present offer of tools and algorithms for phylogenetic analyses, SeaView is especially useful for teaching and for occasional users of such software. SeaView is freely available at http://pbil.univ-lyon1.fr/software/seaview.

Gout J.F.,CNRS Biometry and Evolutionary Biology Laboratory
PLoS genetics | Year: 2010

The understanding of selective constraints affecting genes is a major issue in biology. It is well established that gene expression level is a major determinant of the rate of protein evolution, but the reasons for this relationship remain highly debated. Here we demonstrate that gene expression is also a major determinant of the evolution of gene dosage: the rate of gene losses after whole genome duplications in the Paramecium lineage is negatively correlated to the level of gene expression, and this relationship is not a byproduct of other factors known to affect the fate of gene duplicates. This indicates that changes in gene dosage are generally more deleterious for highly expressed genes. This rule also holds for other taxa: in yeast, we find a clear relationship between gene expression level and the fitness impact of reduction in gene dosage. To explain these observations, we propose a model based on the fact that the optimal expression level of a gene corresponds to a trade-off between the benefit and cost of its expression. This COSTEX model predicts that selective pressure against mutations changing gene expression level or affecting the encoded protein should on average be stronger in highly expressed genes and hence that both the frequency of gene loss and the rate of protein evolution should correlate negatively with gene expression. Thus, the COSTEX model provides a simple and common explanation for the general relationship observed between the level of gene expression and the different facets of gene evolution.

Peres-Neto P.R.,University of Quebec at Montreal | Leibold M.A.,University of Texas at Austin | Dray S.,CNRS Biometry and Evolutionary Biology Laboratory
Ecology | Year: 2012

Patterns in biodiversity and species coexistence are the result of multiple interacting processes including evolutionary history, trait variation, species interactions, dispersal, environmental variation, and landscape heterogeneity. Exploring patterns of biodiversity across space is perhaps the best integrative method (in contrast to the scarcity of temporal data) to interpret the influence of these multiple and interactive effects in determining community assembly, but it is still underdeveloped. Two emerging fields, metacommunity ecology and community phylogenetics, have been making relevant, though rather independent, progress toward understanding how communities are assembled in space. Our main goals were twofold. First, we described a heuristical framework to merge these two fields into "metacommunity phylogenetics." The main goal of this framework is to provide a way to think about how niche properties of species arranged across the environment and different spatial scales influence the process of community assembly. Second, we developed an analytical framework to link niche properties based on trait and phylogenetics to environmental and spatial variation. In order to assess the performance of the framework, we used extensive computer simulations of community assembly to show that the procedure is robust under a variety of scenarios. © 2012 by the Ecological Society of America.

Gamelon M.,CNRS Biometry and Evolutionary Biology Laboratory
Biology letters | Year: 2013

To maximize long-term average reproductive success, individuals can diversify the phenotypes of offspring produced within a reproductive event by displaying the 'coin-flipping' tactic. Wild boar (Sus scrofa scrofa) females have been reported to adopt this tactic. However, whether the magnitude of developmental plasticity within a litter depends on stochasticity in food resources has not been yet investigated. From long-term monitoring, we found that juvenile females produced similar-sized fetuses within a litter independent of food availability. By contrast, adult females adjusted their relative allocation to littermates to the amount of food resources, by providing a similar allocation to all littermates in years of poor food resources but producing highly diversified offspring phenotypes within a litter in years of abundant food resources. By minimizing sibling rivalry, such a plastic reproductive tactic allows adult wild boar females to maximize the number of littermates for a given breeding event.

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