scholarly journals Effects of phenotypic robustness on adaptive evolutionary dynamics

2019 ◽  
Author(s):  
Emanuele Rigato ◽  
Giuseppe Fusco
Keyword(s):  
Evolutionary Dynamics ◽  
Experimental Studies ◽  
Threshold Effect ◽  
Genetic Mutation ◽  
Necessary Condition ◽  
Biological Organization ◽  
Positive Role ◽  
Origin And Evolution ◽  
Quasispecies Model ◽  
Phenotypic Robustness

AbstractTheoretical and experimental studies have provided evidence for a positive role of phenotype resistance to genetic mutation in enhancing long-term adaptation to novel environments. With the aim of contributing to an understanding of the origin and evolution of phenotypic robustness to genetic mutations in organismal systems, we adopted a theoretical approach, elaborating on a classical mathematical formalizations of evolutionary dynamics, the quasispecies model. We show that a certain level of phenotypic robustness is not only a favourable condition for adaptation to occur, but that it is also a necessary condition for short-term adaptation in most real organismal systems. This appears as a threshold effect, i.e. as a minimum level of phenotypic robustness (critical robustness) below which evolutionary adaptation cannot consistently occur or be maintained, even in the case of sizably selection coefficients and in the absence of any drift effect. These results, are in agreement with the observed pervasiveness of robustness at different levels of biological organization, from molecules to whole organisms.

scholarly journals A heuristic model of the effects of phenotypic robustness in adaptive evolution

2020 ◽  
Author(s):  
Emanuele Rigato ◽  
Giuseppe Fusco
Keyword(s):  
Evolutionary Dynamics ◽  
Deterministic Model ◽  
Necessary Condition ◽  
Heuristic Model ◽  
Stochastic Effects ◽  
Simulation Testing ◽  
Phenotypic Robustness ◽  
Parameter Values ◽  
Theoretical Results ◽  
Very High

AbstractA recent theoretical, deterministic model of the effects of phenotypic robustness on adaptive evolutionary dynamics showed that a certain level of phenotypic robustness (critical robustness) is a necessary condition for adaptation to occur and to be maintained in the course of evolution in most real organismal systems. We built an individual-based heuristic model to verify the soundness of these theoretical results through computer simulation, testing expectations under a range of scenarios for the relevant parameters of the evolutionary dynamics. These include the mutation probability, the presence of stochastic effects, the introduction of environmental influences and the possibility for some features of the population (like selection coefficients and phenotypic robustness) to change themselves during adaptation. Overall, we found a good match between observed and expected results, even for evolutionary parameter values that violate some of the assumptions of the deterministic model, and that robustness can itself evolve. However, from more than one simulation it appears that very high robustness values, higher than the critical value, can limit or slow-down adaptation. This possible trade-off was not predicted by the deterministic model.

Transmission rate conditions for distributed filtering in sensor networks against eavesdropper

2021 ◽  
pp. 014233122110056
Author(s):  
Bingya Zhao ◽  
Ya Zhang
Keyword(s):  
Sensor Networks ◽  
Topological Entropy ◽  
Kalman Filtering ◽  
Transmission Rate ◽  
Necessary Condition ◽  
Estimation Errors ◽  
Positive Role ◽  
Filtering Algorithm ◽  
Wiretap Channels ◽  
Kalman Filtering Algorithm

This paper studies the distributed secure estimation problem of sensor networks (SNs) in the presence of eavesdroppers. In an SN, sensors communicate with each other through digital communication channels, and the eavesdropper overhears the messages transmitted by the sensors over fading wiretap channels. The increasing transmission rate plays a positive role in the detectability of the network while playing a negative role in the secrecy. Two types of SNs under two cooperative filtering algorithms are considered. For networks with collectively observable nodes and the Kalman filtering algorithm, by studying the topological entropy of sensing measurements, a sufficient condition of distributed detectability and secrecy, under which there exists a code–decode strategy such that the sensors’ estimation errors are bounded while the eavesdropper’s error grows unbounded, is given. For collectively observable SNs under the consensus Kalman filtering algorithm, by studying the topological entropy of the sensors’ covariance matrices, a necessary condition of distributed detectability and secrecy is provided. A simulation example is given to illustrate the results.

scholarly journals Cbx2, a PcG Family Gene, Plays a Regulatory Role in Medaka Gonadal Development

2020 ◽  
Vol 21 (4) ◽  
pp. 1288
Author(s):  
Qinghe Chao ◽  
Fengfeng Shen ◽  
Yidong Xue ◽  
Jikui Wu ◽  
Junling Zhang
Keyword(s):  
In Situ Hybridization ◽  
Fluorescent In Situ Hybridization ◽  
Marker Gene ◽  
Gonadal Development ◽  
Genetic Mutation ◽  
Polycomb Group ◽  
Positive Role ◽  
Family Gene ◽  
Functional Deficiency

Chromobox homolog 2 (CBX2), a key member of the polycomb group (PcG) family, is essential for gonadal development in mammals. A functional deficiency or genetic mutation in cbx2 can lead to sex reversal in mice and humans. However, little is known about the function of cbx2 in gonadal development in fish. In this study, the cbx2 gene was identified in medaka, which is a model species for the study of gonadal development in fish. Transcription of cbx2 was abundant in the gonads, with testicular levels relatively higher than ovarian levels. In situ hybridization (ISH) revealed that cbx2 mRNA was predominately localized in spermatogonia and spermatocytes, and was also observed in oocytes at stages I, II, and III. Furthermore, cbx2 and vasa (a marker gene) were co-localized in germ cells by fluorescent in situ hybridization (FISH). After cbx2 knockdown in the gonads by RNA interference (RNAi), the sex-related genes, including sox9 and foxl2, were influenced. These results suggest that cbx2 not only plays a positive role in spermatogenesis and oogenesis but is also involved in gonadal differentiation through regulating the expression levels of sex-related genes in fish.

scholarly journals Effects of Supplementation with Natural Antioxidants on Oocytes and Preimplantation Embryos

Antioxidants ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 612 ◽  
Author(s):  
Maria Cristina Budani ◽  
Gian Mario Tiboni
Keyword(s):  
Experimental Studies ◽  
Natural Antioxidants ◽  
Current Data ◽  
Preimplantation Embryos ◽  
Clinical Value ◽  
Positive Role ◽  
Vitro Fertilization ◽  
Ivf Outcomes ◽  
Positive Effects

For most infertile couples, in vitro fertilization (IVF) represents the only chance to conceive. Given the limited success of IVF procedures, novel approaches are continuously tested with the aim of improving IVF outcomes. Growing attention is devoted today to the potential benefit of natural antioxidants in the optimization of infertility treatments. This review summarizes current data in this context, focusing on both experimental studies on oocytes/embryos and clinical trials on antioxidants supplementation. Based on information gained from experimental studies, antioxidant supplementation may have beneficial effects on IVF outcomes in terms of quality and cryotolerance of in vitro produced embryos, together with positive effects on in vitro maturation oocytes and on early embryonic development. Unfortunately, from the clinical side, there is a paucity of evidence favoring the protective qualities of antioxidants. Among the antioxidants considered, coenzyme Q10 may be regarded as one of the most promising for its positive role in rescuing the oxidative stress-induced damages, but further data are needed. It is concluded that further trials are necessary to characterize the potential clinical value of antioxidants in IVF treatments.

scholarly journals Evolutionary dynamics drives role specialization in a community of players

2020 ◽  
Vol 17 (168) ◽  
pp. 20200174 ◽  
Author(s):  
Danyang Jia ◽  
Xinyu Wang ◽  
Zhao Song ◽  
Ivan Romić ◽  
Xuelong Li ◽  
...  
Keyword(s):  
Evolutionary Dynamics ◽  
Experimental Studies ◽  
Current Standard ◽  
Complex Processes ◽  
Spatial Games ◽  
Powerful Means ◽  
New Type ◽  
Standard Models ◽  
Natural Fact ◽  
Role Specialization

The progression of game theory from classical to evolutionary and spatial games provided a powerful means to study cooperation, and enabled a better understanding of general cooperation-promoting mechanisms. However, current standard models assume that at any given point players must choose either cooperation or defection, meaning that regardless of the spatial structure in which they exist, they cannot differentiate between their neighbours and adjust their behaviour accordingly. This is at odds with interactions among organisms in nature who are well capable of behaving differently towards different members of their communities. We account for this natural fact by introducing a new type of player—dubbed link players—who can adjust their behaviour to each individual neighbour. This is in contrast to more common node players whose behaviour affects all neighbours in the same way. We proceed to study cooperation in pure and mixed populations, showing that cooperation peaks at moderately low densities of link players. In such conditions, players naturally specialize in different roles. Node players tend to be either cooperators or defectors, while link players form social insulation between cooperative and defecting clusters by acting both as cooperators and defectors. Such fairly complex processes emerging from a simple model reflect some of the complexities observed in experimental studies on social behaviour in microbes and pave a way for the development of richer game models.

scholarly journals AOP4EUpest: mapping of pesticides in adverse outcome pathways using a text mining tool

2020 ◽  
Vol 36 (15) ◽  
pp. 4379-4381 ◽  
Author(s):  
Florence Jornod ◽  
Marylène Rugard ◽  
Luc Tamisier ◽  
Xavier Coumoul ◽  
Helle R Andersen ◽  
...  
Keyword(s):  
Adverse Outcome ◽  
Experimental Studies ◽  
Adverse Outcomes ◽  
Vulnerable Groups ◽  
Supplementary Information ◽  
Human Populations ◽  
Biological Organization ◽  
Linear Representations ◽  
Pubmed Database ◽  
Adverse Outcome Pathways

Abstract Motivation Exposure to pesticides may lead to adverse health effects in human populations, in particular vulnerable groups. The main long-term health concerns are neurodevelopmental disorders, carcinogenicity as well as endocrine disruption possibly leading to reproductive and metabolic disorders. Adverse outcome pathways (AOP) consist in linear representations of mechanistic perturbations at different levels of the biological organization. Although AOPs are chemical-agnostic, they can provide a better understanding of the Mode of Action of pesticides and can support a rational identification of effect markers. Results With the increasing amount of scientific literature and the development of biological databases, investigation of putative links between pesticides, from various chemical groups and AOPs using the biological events present in the AOP-Wiki database is now feasible. To identify co-occurrence between a specific pesticide and a biological event in scientific abstracts from the PubMed database, we used an updated version of the artificial intelligence-based AOP-helpFinder tool. This allowed us to decipher multiple links between the studied substances and molecular initiating events, key events and adverse outcomes. These results were collected, structured and presented in a web application named AOP4EUpest that can support regulatory assessment of the prioritized pesticides and trigger new epidemiological and experimental studies. Availability and implementation http://www.biomedicale.parisdescartes.fr/aop4EUpest/home.php. Supplementary information Supplementary data are available at Bioinformatics online.

scholarly journals Phase Transitions in Virology

2020 ◽  
Author(s):  
Ricard Sole ◽  
Josep Sardanyes ◽  
Santiago F. Elena
Keyword(s):  
Phase Transitions ◽  
Genetic Information ◽  
Molecular Mechanisms ◽  
Evolutionary Dynamics ◽  
Living Organism ◽  
Genome Replication ◽  
Minimal Models ◽  
Biological Organization ◽  
Symbiotic Relationships ◽  
Replication Gene

Viruses have established symbiotic relationships with almost every other living organism on Earth and at all levels of biological organization, from other viruses up to entire ecosystems. In most cases, peacefully coexisting with their hosts, but in most relevant cases, parasitizing them and inducing diseases. Viruses are playing an essential role in shaping the eco-evolutionary dynamics of their hosts, and also have been involved in some of the major evolutionary innovations either by working as vectors of genetic information or by being themselves coopted by the host into their genomes. Viruses can be studied at different levels of biological organization, from the molecular mechanisms of genome replication, gene expression and encapsidation to global pandemics. All these levels are different and yet connected through the presence of threshold conditions allowing for the formation of a capsid, the loss of genetic information or epidemic spreading. These thresholds, as it occurs with temperatures separating phases in a liquid, define sharp qualitative types of behaviour. These {\em phase transitions} are very well known in physics. They have been studied by means of simple, but powerful models able to capture their essential properties, allowing to understand them. Can the physics of phase transitions be an inspiration for our understanding of viral dynamics at different scales? Here we review the best-known examples of transition phenomena in virology and their simplest mathematical modelling approaches. We suggest that the advantages of abstract, simplified pictures used in physics are also the key to properly understand the origins and evolution of complexity in viruses. By means of several examples, we explore this multilevel landscape and how minimal models provide deep insights into a diverse array of problems. The relevance of these transitions in connecting dynamical patterns across levels and their evolutionary and clinical implications are outlined.

Within-Host Viral Diversity: A Window into Viral Evolution

2020 ◽  
Vol 7 (1) ◽  
pp. 63-81 ◽  
Author(s):  
Adam S. Lauring
Keyword(s):  
Large Scale ◽  
Evolutionary Dynamics ◽  
Viral Evolution ◽  
Experimental Studies ◽  
Disease Spread ◽  
Viral Diversity ◽  
Host Diversity ◽  
Models Of Disease ◽  
Host Evolution ◽  
Viral Sequencing

The evolutionary dynamics of a virus can differ within hosts and across populations. Studies of within-host evolution provide an important link between experimental studies of virus evolution and large-scale phylodynamic analyses. They can determine the extent to which global processes are recapitulated on local scales and how accurately experimental infections model natural ones. They may also inform epidemiologic models of disease spread and reveal how host-level dynamics contribute to a virus's evolution at a larger scale. Over the last decade, advances in viral sequencing have enabled detailed studies of viral genetic diversity within hosts. I review how within-host diversity is sampled, measured, and expressed, and how comparative studies of viral diversity can be leveraged to elucidate a virus's evolutionary dynamics. These concepts are illustrated with detailed reviews of recent research on the within-host evolution of influenza virus, dengue virus, and cytomegalovirus.

scholarly journals Effects of Phenotypic Robustness on Adaptive Evolutionary Dynamics

2020 ◽  
Vol 47 (3) ◽  
pp. 233-239 ◽  
Author(s):  
Emanuele Rigato ◽  
Giuseppe Fusco
Keyword(s):  
Evolutionary Dynamics ◽  
Phenotypic Robustness

Evolution of Linguistic Diversity in a Simple Communication System

1998 ◽  
Vol 4 (1) ◽  
pp. 109-124 ◽  
Author(s):  
Takaya Arita ◽  
Yuhji Koyama
Keyword(s):  
Communication System ◽  
Evolutionary Dynamics ◽  
Linguistic Diversity ◽  
Dynamic Equilibrium ◽  
Cooperative Behavior ◽  
Abstract Model ◽  
Agent Based ◽  
Origin And Evolution ◽  
Current State ◽  
Synthetic Modeling

This article reports on the current state of our efforts to shed light on the origin and evolution of linguistic diversity using synthetic modeling and artificial life techniques. We construct a simple abstract model of a communication system that has been designed with regard to referential signaling in nonhuman animals. We analyze the evolutionary dynamics of vocabulary sharing based on these experiments. The results show that mutation rates, population size, and resource restrictions define the classes of vocabulary sharing. We also see a dynamic equilibrium, where two states, a state with one dominant shared word and a state with several dominant shared words, take turns appearing. We incorporate the idea of the abstract model into a more concrete situation and present an agent-based model to verify the results of the abstract model and to examine the possibility of using linguistic diversity in the field of distributed AI and robotics. It has been shown that the evolution of linguistic diversity in vocabulary sharing will support cooperative behavior in a population of agents.

Sign in / Sign up

Export Citation Format

Share Document