scholarly journals When three traits make a line: evolution of phenotypic plasticity and genetic assimilation through linear reaction norms in stochastic environments

2016 ◽  
Vol 30 (3) ◽  
pp. 486-500 ◽  
Author(s):  
T. Ergon ◽  
R. Ergon
Keyword(s):  
Phenotypic Plasticity ◽  
Genetic Assimilation ◽  
Reaction Norms ◽  
Stochastic Environments ◽  
Linear Reaction

scholarly journals When three traits make a line: Evolution of phenotypic plasticity and genetic assimilation through linear reaction norms in stochastic environments

2015 ◽  
Author(s):  
Torbjorn Ergon ◽  
Rolf Ergon
Keyword(s):  
Phenotypic Plasticity ◽  
Genetic Correlations ◽  
Reaction Norm ◽  
Genetic Effects ◽  
Environmental Perception ◽  
Genetic Assimilation ◽  
Reaction Norms ◽  
Environmental Value ◽  
Linear Reaction ◽  
Definition Of

Genetic assimilation results from selection on phenotypic plasticity, but quantitative genetics models of linear reaction norms considering intercept and slope as traits do not fully incorporate the process of genetic assimilation. We argue that intercept-slope reaction norm models are insufficient representations of genetic effects on linear reaction norms, and that considering reaction norm intercept as a trait is unfortunate because the definition of this trait relates to a specific environmental value (zero) and confounds genetic effects on reaction norm elevation with genetic effects on environmental perception. Instead we suggest a model with three traits representing genetic effects that respectively (i) are independent of the environment, (ii) alter the sensitivity of the phenotype to the environment, and (iii) determine how the organism perceives the environment. The model predicts that, given sufficient additive genetic variation in environmental perception, the environmental value at which reaction norms tend to cross will respond rapidly to selection after an abrupt environmental change, and eventually become equal to the new mean environment. This readjustment of the zone of canalization becomes completed without changes in genetic correlations, genetic drift or imposing any fitness costs on maintaining plasticity. The asymptotic evolutionary outcome of this three-trait linear reaction norm generally entails a lower degree of phenotypic plasticity than the two-trait model, and maximum expected fitness does not occur at the mean trait values in the population.

scholarly journals Maintenance of genetic variation in phenotypic plasticity: the role of environmental variation

2000 ◽  
Vol 76 (3) ◽  
pp. 295-304 ◽  
Author(s):  
GERDIEN de JONG ◽  
SERGEY GAVRILETS
Keyword(s):  
Genetic Variation ◽  
Phenotypic Plasticity ◽  
Temporal Variation ◽  
Genetic Variance ◽  
Reaction Norm ◽  
Reaction Norms ◽  
Stabilizing Selection ◽  
Variable Environment ◽  
Linear Reaction

We study genetic variation in phenotypic plasticity maintained by a balance between mutation and weak stabilizing selection. We consider linear reaction norms allowing for spatial and/or temporal variation in the environments of development and selection. We show that the overall genetic variation maintained does not depend on whether the trait is plastic or not. The genetic variances in height and slope of a linear reaction norm, and their covariance, are predicted to decrease with the variation in the environment. Non-pleiotropic loci influencing either height or slope are expected to decrease the genetic variance in slope relative to that in height. Decrease in the ratio of genetic variance in slope to genetic variance in height with increasing variation in the environment presents a test for the presence of loci that only influence the slope, and not the height. We use data on Drosophila to test the theory. In seven of eight pair-wise comparisons genetic variation in reaction norm is higher in a less variable environment than in a more variable environment, which is in accord with the model's predictions.

Predator-induced Contemporary Evolution, Phenotypic Plasticity, and the Evolution of Reaction Norms in Guppies

Copeia ◽  
2017 ◽  
Vol 105 (3) ◽  
pp. 514-522 ◽  
Author(s):  
Swanne P. Gordon ◽  
Andrew P. Hendry ◽  
David N. Reznick
Keyword(s):  
Phenotypic Plasticity ◽  
Reaction Norms ◽  
Contemporary Evolution
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