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 traits structure and a higher capacity to respond by acclimation. However, the evolutionary responses of traits were generally lower for uranium than salt and the evolutionary responses in the alternating uranium-salt environment were between those of constant environments. Consequently, at the end of the experiment, the population rate of increase were 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 demographic consequences. These changes are partly explain 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.
multiG1
M. DUTILLEUL, J.M. BONZOM, C. LECOMTE, B. GOUSSEN, F. DAIAN, S. GALAS, D. REALE 2014
Rapid evolutionary responses of life history traits to different experimentally-induced pollution in Caenorhabditis elegans
BMC Evolutionary Biology =================================
File name: multiG1.csv
File description: measures of life history traits of Caenorhabditis elegans in different environments during a multi-generationnal experiment. -------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Definition of column headings:
generation: generation in which the individual* was measured (1 to 22)*
environment: environment where the individual* lived (control, salt, uranium, alternating)
replicate: population from where the individual* was sampled (A to X)*
fertility_B96: number of larvae produced by the hermaphrodite before 96h of life
fertility_A96: number of larvae produced by the hermaphrodite after 96h of life
fertility_tot: number of larvae produced by the hermaphrodite in its all life
length_H: body length of the hermaphrodite (in mm)
bend_M: number of body bend of the male in 20 seconds
length_M: body length of the male (in mm).
Missing data are indicated with NA
*Although the data are on the same line to shorten the table, the hermaphrodite and the male measured at each line came from a same replicate but were obviously different individuals
===============================
Contact information: morgan.dutilleul@hotmail.fr
multiG2
M. DUTILLEUL, J.M. BONZOM, C. LECOMTE, B. GOUSSEN, F. DAIAN, S. GALAS, D. REALE
2014
Rapid evolutionary responses of life history traits to different experimentally-induced pollution in Caenorhabditis elegans
BMC Evolutionary Biology
===============================
File name: multiG2.csv
File description: measures of survival, sex ratio and population size of Caenorhabditis elegans populations in different environments
during a multi-generationnal experiment.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Definition of column headings:
generation: generation in which population was measured (1 to 22)
environment: environment where the population lived (control, salt, uranium, alternating)
replicate: denomination of the replicate population through the generations (A to X)
survival: percentage of survival in the replicate population (%)
ratio_M: percentage of male in the replicate population (%)
pop_size: number of individuals in the replicate population
Missing data are indicated with NA
================================
Contact information:
morgan.dutilleul@hotmail.fr