title: Rapid evolutionary responses of life history traits to different experimentally-induced pollutions in Caenorhabditis elegans.
abstract: BACKGROUND
  Anthropogenic disturbances can lead to intense selection pressures on traits and very rapid evolutionary changes. Evolutionary responses to environmental changes, in turn, reflect changes in the genetic structure of the traits, accompanied by a reduction of evolutionary potential of the populations under selection. Assessing the effects of pollutants on the evolutionary responses and on the genetic structure of populations is thus important to understanding the mechanisms that entail specialization to novel environmental conditions or resistance to novel stressors.
  
  
  RESULTS
  Using an experimental evolution approach we exposed Caenorhabditis elegans populations to uranium, salt and alternating uranium-salt environments over 22 generations. We analyzed the changes in the average values of life history traits and the consequences at the demographic level in these populations. We also estimated the phenotypic and genetic (co)variance structure of these traits at different generations. Compared to populations in salt, populations in uranium showed a reduction of the stability of their trait structure and a higher capacity to respond by acclimation. However, the evolutionary responses of traits were generally lower for uranium compared to salt treatment; and the evolutionary responses to the alternating uranium-salt environment were between those of constant environments. Consequently, at the end of the experiment, the population rate of increase was higher in uranium than in salt and intermediate in the alternating environment.
  
  
  CONCLUSIONS
  Our multigenerational experiment confirmed that rapid adaptation to different polluted environments may involve different evolutionary responses resulting in demographic consequences. These changes are partly explained by the effects of the pollutants on the genetic (co)variance structure of traits and the capacity of acclimation to novel conditions. Finally, our results in the alternating environment may confirm the selection of a generalist type in this environment.
authors.affiliation: Département des Sciences Biologiques, Université du Québec À Montréal, Montreal, Canada. morgan.dutilleul@hotmail.fr.|Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV/SERIS/LECO, Cadarache, Bât 183, BP 3, 13115, St Paul-lez-Durance, France. morgan.dutilleul@hotmail.fr.|Université de Montpellier 1, Faculté de pharmacie, Laboratoire de Toxicologie, BP 14491, F-34093, Montpellier Cedex 5, France. morgan.dutilleul@hotmail.fr.
authors.forename: Morgan
authors.initials: M
authors.lastname: Dutilleul
authors.affiliation: Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV/SERIS/LECO, Cadarache, Bât 183, BP 3, 13115, St Paul-lez-Durance, France. jean-marc.bonzom@irsn.fr.
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Bonzom
authors.affiliation: Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV/SERIS/LECO, Cadarache, Bât 183, BP 3, 13115, St Paul-lez-Durance, France. catherine.lecomte-pradines@irsn.fr.
authors.forename: Catherine
authors.initials: C
authors.lastname: Lecomte
authors.affiliation: Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV/SERIS/LECO, Cadarache, Bât 183, BP 3, 13115, St Paul-lez-Durance, France. benoit.goussen@irsn.fr.|Unit "Models for ecotoxicology and toxicology" (METO) INERIS Parc ALATA, BP2 60550, Verneuil-en-Halatte, France. benoit.goussen@irsn.fr.
authors.forename: Benoit
authors.initials: B
authors.lastname: Goussen
authors.affiliation: Institut de Biologie du Développement de Marseille-Luminy, UMR7288, CNRS, F-13288, Marseille Cedex 9, France. daian@ibdml.univmed.fr.
authors.forename: Fabrice
authors.initials: F
authors.lastname: Daian
authors.affiliation: Université de Montpellier 1, Faculté de pharmacie, Laboratoire de Toxicologie, BP 14491, F-34093, Montpellier Cedex 5, France. simon.galas@univ-monpt1.fr.
authors.forename: Simon
authors.initials: S
authors.lastname: Galas
authors.affiliation: Département des Sciences Biologiques, Université du Québec À Montréal, Montreal, Canada. reale.denis@uqam.ca.
authors.forename: Denis
authors.initials: D
authors.lastname: Réale
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D005075:Biological Evolution; D017173:Caenorhabditis elegans / Q000235:genetics* / Q000254:growth & development / Q000502:physiology; D004785:Environmental Pollutants / Q000633:toxicity*; D008018:Life Cycle Stages; D012965:Sodium Chloride / Q000633:toxicity; D014501:Uranium / Q000633:toxicity
chemical_list: D004785:Environmental Pollutants; D012965:Sodium Chloride; D014501:Uranium