Adjusting phenotypes via within‐ and across‐generational plasticity

Abstract

Contents 343I.343II.343III.347IV.348348References348 Summary There is renewed interest in how transgenerational environmental effects, including epigenetic inheritance, contribute to adaptive evolution. The contribution of across‐generation plasticity to adaptation, however, needs to be evaluated within the context of within‐generation plasticity, which is often proposed to contribute more efficiently to adaptation because of the potentially greater accuracy of progeny than parental cues to predict progeny selective environments. We highlight recent empirical studies of transgenerational plasticity, and find that they do not consistently support predictions based on the higher predictive ability of progeny environmental cues. We discuss these findings within the context of the relative predictive ability of maternal and progeny cues, costs and constraints of plasticity in parental and progeny generations, and the dynamic nature of the adaptive value of within‐ and across‐generation plasticity that varies with the process of adaptation itself. Such contingent and dynamically variable selection could account for the diversity of patterns of within‐ and across‐generation plasticity observed in nature, and can influence the adaptive value of the persistence of environmental effects across generations.

Context-Dependent Developmental Effects of Parental Shade Versus Sun Are Mediated by DNA Methylation

“…Such complex patterns of expression arise from the various ways that within- and trans-generational environmental influences are integrated by developing organisms (Leimar and McNamara, 2015; Sultan, 2015; Auge et al, 2017). In some cases, favorable immediate conditions in offspring environments may mask or overcome negative transgenerational effects of parental stress.…”

Multiple simultaneous treatments change plant response from adaptive parental effects to within‐generation plasticity, inArabidopsis thaliana

“…The model was fitted with the lmer function in the R‐package lme4 (Bates et al ). For inference, Satterthwaite's approximation of degrees of freedom was used as implemented in the R‐package lmerTest (Kuznetsova et al ). In addition, using a simple regression the means of all within‐generation and parental treatments for fitness were individually regressed against the corresponding treatment means of flowering time and rosette diameter and flowering time corrected senescence.…”

“…This is because, plants inherit the parental molecular phenotype that can be adjusted to the ‘parental environment’ (Herman and Sultan , 2016). In theory, these effects are advantageous when parental, and offspring environments are correlated (Ezard et al , Leimar and McNamara , Groot et al ), and this is supported by experimental evidence. For instance, offspring of wounded Mimulus guttatus plants showed reduced herbivory damage in two field sites (Colicchio ), and offspring of shaded or non‐shaded Campanulastrum americanum plants showed increased fitness when their light regime matched their parent's environment (Galloway and Etterson ).…”

“…However, this study investigated only one local population and the existence of environmental correlations between generations in this site is not known. Recent studies showed that parental environmental effects tend to be specific for populations or genotypes from different sites congruent with local adaptation (Groot et al , Lampei et al ). Therefore, if not considered, intraspecific variation in adaptive parental effects may be one reason for ambiguous results across diverse studies.…”

“…Recently, optimality models suggested that within‐generation plasticity and transgenerational plasticity need to act together to produce the well‐adapted phenotype (Ezard et al , Leimar and McNamara ). Therefore, they should be jointly studied so that one can be interpreted in the context of the other (Auge et al ). However, experimental studies are rare, though some nice examples exist.…”