scholarly journals Phenotypic plasticity promotes balanced polymorphism in periodic environments by a genomic storage effect

2016 ◽  
Author(s):  
Davorka Gulisija ◽  
Yuseob Kim ◽  
Joshua B. Plotkin
Keyword(s):  
Phenotypic Plasticity ◽  
Large Range ◽  
Genetic Model ◽  
Effect Sizes ◽  
Storage Effect ◽  
Recombination Rates ◽  
Modifier Locus ◽  
Balanced Polymorphism ◽  
Analytical Approximations ◽  
Varying Environments

Phenotypic plasticity is known to evolve in perturbed habitats, where it alleviates the deleterious effects of selection. But the effects of plasticity on levels of genetic polymorphism, an important precursor to adaptation in temporally varying environments, are unclear. Here we develop a haploid, two-locus population-genetic model to describe the interplay between a plasticity modifier locus and a target locus subject to periodically varying selection. We find that the interplay between these two loci can produce a 'genomic storage effect' that promotes balanced polymorphism over a large range of parameters, in the absence of all other conditions known to maintain genetic variation. The genomic storage effect arises as recombination allows alleles at the two loci to escape more harmful genetic backgrounds and associate in haplotypes that persist until environmental conditions change. Using both Monte Carlo simulations and analytical approximations we quantify the strength of the genomic storage effect across a range of selection pressures, recombination rates, plasticity modifier effect sizes, and environmental periods.

scholarly journals Phenotypic plasticity promotes recombination and gene clustering in periodic environments

2017 ◽  
Author(s):  
Davorka Gulisija ◽  
Joshua B. Plotkin
Keyword(s):  
Phenotypic Plasticity ◽  
Natural Populations ◽  
Gene Clustering ◽  
Analytic Approximation ◽  
Red Queen Hypothesis ◽  
Modifier Locus ◽  
Balanced Polymorphism ◽  
Target Locus ◽  
Single Target ◽  
Host Parasite

While theory offers clear predictions for when recombination will evolve in changing environments, it is unclear what natural scenarios can generate the necessary conditions. The Red Queen hypothesis provides one such scenario in natural populations, but it requires interaction with antagonistic species such as host-parasite systems. We present a novel scenario for the evolution of recombination in finite populations: the genomic storage effect due to phenotypic plasticity. Using an analytic approximation and Monte Carlo simulations we demonstrate that balanced polymorphism and recombination evolve between a target locus that codes for a seasonally selected trait and a plasticity modifier locus that modulates the effects of target-locus alleles. Unlike in prior models, evolution of recombination by this plasticity effect does not require antagonistic inter-specific interactions or a steady influx of mutation, and it occurs even when a single target locus expresses a trait under selection. Furthermore, we show that selection will suppress the recombination rate among multiple polymorphic target loci, even in the absence of epistasis among them, which produces a cluster of linked loci under selection. These results provide a novel biological scenario for the evolution of recombination and supergenes.

scholarly journals Phenotypic plasticity promotes recombination and gene clustering in periodic environments

2017 ◽  
Author(s):  
Davorka Gulisija ◽  
Joshua B. Plotkin
Keyword(s):  
Phenotypic Plasticity ◽  
Natural Populations ◽  
Gene Clustering ◽  
Analytic Approximation ◽  
Red Queen Hypothesis ◽  
Modifier Locus ◽  
Balanced Polymorphism ◽  
Target Locus ◽  
Single Target ◽  
Host Parasite

While theory offers clear predictions for when recombination will evolve in changing environments, it is unclear what natural scenarios can generate the necessary conditions. The Red Queen hypothesis provides one such scenario in natural populations, but it requires interaction with antagonistic species such as host-parasite systems. We present a novel scenario for the evolution of recombination in finite populations: the genomic storage effect due to phenotypic plasticity. Using an analytic approximation and Monte Carlo simulations we demonstrate that balanced polymorphism and recombination evolve between a target locus that codes for a seasonally selected trait and a plasticity modifier locus that modulates the effects of target-locus alleles. Unlike in prior models, evolution of recombination by this plasticity effect does not require antagonistic inter-specific interactions or a steady influx of mutation, and it occurs even when a single target locus expresses a trait under selection. Furthermore, we show that selection will suppress the recombination rate among multiple polymorphic target loci, even in the absence of epistasis among them, which produces a cluster of linked loci under selection. These results provide a novel biological scenario for the evolution of recombination and supergenes.

scholarly journals Can Social Desirability Be Detected Statistically at the Macro-Sociological Level?

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Walter R. Schumm ◽  
◽  
Duane W. Crawford ◽  
Keyword(s):  
Social Desirability ◽  
Large Range ◽  
Empirical Studies ◽  
Effect Sizes ◽  
Research Quality ◽  
Same Sex ◽  
Future Directions ◽  
Empirical Tests ◽  
Same Sex Parents ◽  
Suppressor Variable

While a few have argued that social science has been subject to progressive biases, others have discounted such ideas. However, no one has yet performed empirical tests over a large range of studies for such possible bias, which we label macro-level social desirability (MLSD). Combining the results from fifty-nine empirical studies that assessed rates of nonheterosexuality among children of same-sex parents, we found that the higher the maximum rates reported, the less likely those reports were to have been cited in Google Scholar by counts or by annual rate, which may reflect MLSD. However, after several statistical controls, the association for counts became non-significant, while the association for rates became stronger, although the effect sizes were in a moderate (d = .28 or higher) to large range (d, up to .68) by either analysis. Generally, research quality acted as a suppressor variable for MLSD but was significantly related to both counts and rates of citations, indicating that higher quality articles were more likely to have been cited, even controlling for the number of years since first publication. Higher quality articles were slightly more likely to report higher rates of nonheterosexuality among children of same-sex parents. We discuss implications of our findings and suggest future directions of research.

scholarly journals Phenotypic Variation and Plasticity in the Colonizing Species Xanthium Strumarium L. (Noogoora Burr)

1981 ◽  
Vol 34 (6) ◽  
pp. 639 ◽  
Author(s):  
GF Moran ◽  
DR Marshall ◽  
WJ Müller
Keyword(s):  
Phenotypic Plasticity ◽  
Phenotypic Variation ◽  
Reproductive Strategies ◽  
Quantitative Traits ◽  
Genotypic Variation ◽  
Xanthium Strumarium ◽  
Quantitative Characters ◽  
Major Mode ◽  
Varying Environments ◽  
Colonizing Ability

Levels of genotypic (O'G 2) and environmentally induced (O'E2) variation for 15 quantitative characters were estimated in seven populations of the four naturalized races of X. strumarium in Australia. Estimates of O'G2 indicated that populations of X. strumarium were often genetically variable for quantitative traits. However, for the majority of the characters studied, O'E2 was a larger component of the total phenotypic variation than was O'G 2 , indicating that phenotypic plasticity is the major mode of adaptation of this species to variable and varying environments. Few significant differences were found among the races, or among populations within a race, in either O'G2 or O'E2. This suggests that marked differences in colonizing ability of the four races of X. strumarium are probably not .due to differences in phenotypic plasticity (individual buffering) or genotypic variation (populational buffering) but to differences in such factors as their reproductive strategies and photoperiodic requirements for flowering.

scholarly journals What drives the evolution of condition-dependent recombination in diploids? Some insights from simulation modelling

2017 ◽  
Vol 372 (1736) ◽  
pp. 20160460 ◽  
Author(s):  
Sviatoslav R. Rybnikov ◽  
Zeev M. Frenkel ◽  
Abraham B. Korol
Keyword(s):  
Recombination Rate ◽  
External Environment ◽  
Theoretical Models ◽  
Simulation Modelling ◽  
Condition Dependence ◽  
Rate Variation ◽  
Theoretical Studies ◽  
Recombination Rates ◽  
Modifier Locus ◽  
Recombination Rate Variation

While the evolutionary advantages of non-zero recombination rates have prompted diverse theoretical explanations, the evolution of essential recombination features remains underexplored. We focused on one such feature, the condition dependence of recombination, viewed as the variation in within-generation sensitivity of recombination to external (environment) and/or internal (genotype) conditions. Limited empirical evidence for its existence comes mainly from diploids, whereas theoretical models show that it only easily evolves in haploids. The evolution of condition-dependent recombination can be explained by its advantage for the selected system (indirect effect), or by benefits to modifier alleles, ensuring this strategy regardless of effects on the selected system (direct effect). We considered infinite panmictic populations of diploids exposed to a cyclical two-state environment. Each organism had three selected loci. Examining allele dynamics at a fourth, selectively neutral recombination modifier locus, we frequently observed that a modifier allele conferring condition-dependent recombination between the selected loci displaced the allele conferring the optimal constant recombination rate. Our simulations also confirm the results of theoretical studies showing that condition-dependent recombination cannot evolve in diploids on the basis of direct fitness-dependent effects alone. Therefore, the evolution of condition-dependent recombination in diploids can be driven by indirect effects alone, i.e. by modifier effects on the selected system. This article is part of the themed issue ‘Evolutionary causes and consequences of recombination rate variation in sexual organisms’.

scholarly journals The role of phenotypic plasticity in the establishment of range margins

2021 ◽  
Author(s):  
Martin Eriksson ◽  
Marina Rafajlović
Keyword(s):  
Phenotypic Plasticity ◽  
Genetic Variance ◽  
Natural Populations ◽  
Analytical Approximations ◽  
Variable Environments ◽  
Key Factor ◽  
Modelling Studies ◽  
Adaptive Phenotypic Plasticity ◽  
The Cost

It has been argued that adaptive phenotypic plasticity may facilitate range expansions over spatially and temporally variable environments. However, plasticity may induce fitness costs. This may hinder the evolution of plasticity. Earlier modelling studies examined the role of plasticity during range expansions of populations with fixed genetic variance. However, genetic variance evolves in natural populations. This may critically alter model outcomes. We ask: How does the capacity for plasticity in populations with evolving genetic variance alter range margins that populations without the capacity for plasticity are expected to attain? We answered this question using computer simulations and analytical approximations. We found a critical plasticity cost above which the capacity for plasticity has no impact on the expected range of the population. Below the critical cost, by contrast, plasticity facilitates range expansion, extending the range in comparison to that expected for populations without plasticity. We further found that populations may evolve plasticity to buffer temporal environmental fluctuations, but only when the plasticity cost is below the critical cost. Thus, the cost of plasticity is a key factor involved in range expansions of populations with the potential to express plastic response in the adaptive trait.

scholarly journals Phenotypic plasticity promotes recombination and gene clustering in periodic environments

2016 ◽  
Keyword(s):  
Phenotypic Plasticity ◽  
Genetic Recombination ◽  
Gene Clustering ◽  
Analytic Approximation ◽  
Red Queen Hypothesis ◽  
Modifier Locus ◽  
Changing Environments ◽  
Target Locus ◽  
Host Parasite ◽  
The Impact

AbstractThe impact of changing environments on the evolution of genetic recombination is still unclear. While the Red Queen hypothesis provides a reasonable explanation for recombination, it requires coevolution with antagonistic species, such as host-parasite systems. We present a novel scenario for the evolution of recombination in changing environments: the genomic storage effect due to phenotypic plasticity. Using an analytic approximation and Monte Carlo simulations, we demonstrate that recombination evolves between a target locus that determines fitness, and a modifier locus that modulates the effects of alleles at the target. Evolution of recombination by this plasticity effect does not require antagonistic inter-specific interactions and, unlike in previous models, it occurs when only one target locus codes for a trait under selection. Furthermore, if the effects of multiple target loci are modified by the same plasticity locus, then the recombination rate among the target loci will tend to decrease, clustering the loci that influence a trait. These results provide a novel scenario for the evolution of recombination, highlighting the importance of phenotypic plasticity for recombination modification.

The aquatic and littoral forms of the Patagonian frog Atelognathus patagonicus (Batrachylinae): new molecular evidence

Zootaxa ◽  
2011 ◽  
Vol 3129 (1) ◽  
pp. 62 ◽  
Author(s):  
LIZA B. MARTINAZZO ◽  
NÉSTOR G. BASSO ◽  
CARMEN A. ÚBEDA
Keyword(s):  
Phenotypic Plasticity ◽  
Genetic Variability ◽  
Genetic Differentiation ◽  
Control Region ◽  
National Park ◽  
Diversity Index ◽  
Morphological Data ◽  
Molecular Evidence ◽  
Balanced Polymorphism ◽  
And Control

Atelognathus patagonicus is one of the eight species included in the Patagonian genus Atelognathus, an endemic frog occurring in the system of endorheic basaltic lagoons of the Laguna Blanca National Park (PNLB), Neuquén, Argentina. Based on morphological data, Cei & Roig (1968) described two forms of A. patagonicus, which they called “aquatic” and “littoral”. These morphotypes were first suggested to belong to different species, but later, Cei (1972) proposed that both forms represent a balanced polymorphism within A. patagonicus. More recently, an ecomorphological study showed that aquatic and littoral are reversible forms of the same individual (phenotypic plasticity). In this paper we compare the morphotypes of A. patagonicus using nucleotide sequences of the mtDNA (cytochrome b and control region) in order to test the existence of genetic differentiation between the aquatic and littoral forms. In addition, we present data of genetic variability of A. patagonicus from the Laguna Blanca system. We did not detect genetic differentiation between littoral and aquatic morphotypes for both genes studied. This observation is consistent with the hypothesis of phenotypic plasticity. In contrast with the expected results for low vagility organisms, the diversity index observed in A. patagonicus revealed a low genetic variability.

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