scholarly journals Dynamics and variability in the pleiotropic effects of adaptation in laboratory budding yeast populations

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Christopher W Bakerlee ◽  
Angela M Phillips ◽  
Alex N Nguyen Ba ◽  
Michael M Desai
Keyword(s):  
Budding Yeast ◽  
Pleiotropic Effects ◽  
Evolutionary Adaptation ◽  
Complex Environments ◽  
Space And Time ◽  
Constant Environment ◽  
Fluctuating Environments ◽  
Evolutionary Trajectories ◽  
Multiple Environments ◽  
Over Time

Evolutionary adaptation to a constant environment is driven by the accumulation of mutations which can have a range of unrealized pleiotropic effects in other environments. These pleiotropic consequences of adaptation can influence the emergence of specialists or generalists, and are critical for evolution in temporally or spatially fluctuating environments. While many experiments have examined the pleiotropic effects of adaptation at a snapshot in time, very few have observed the dynamics by which these effects emerge and evolve. Here, we propagated hundreds of diploid and haploid laboratory budding yeast populations in each of three environments, and then assayed their fitness in multiple environments over 1000 generations of evolution. We find that replicate populations evolved in the same condition share common patterns of pleiotropic effects across other environments, which emerge within the first several hundred generations of evolution. However, we also find dynamic and environment-specific variability within these trends: variability in pleiotropic effects tends to increase over time, with the extent of variability depending on the evolution environment. These results suggest shifting and overlapping contributions of chance and contingency to the pleiotropic effects of adaptation, which could influence evolutionary trajectories in complex environments that fluctuate across space and time.

scholarly journals Dynamics and variability in the pleiotropic effects of adaptation in laboratory budding yeast populations

2021 ◽  
Author(s):  
Christopher W Bakerlee ◽  
Angela M Phillips ◽  
Alex N Nguyen Ba ◽  
Michael M Desai
Keyword(s):  
Budding Yeast ◽  
Pleiotropic Effects ◽  
Evolutionary Adaptation ◽  
Complex Environments ◽  
Space And Time ◽  
Constant Environment ◽  
Fluctuating Environments ◽  
Evolutionary Trajectories ◽  
Multiple Environments ◽  
Over Time

Evolutionary adaptation to a constant environment is driven by the accumulation of mutations which can have a range of unrealized pleiotropic effects in other environments. These pleiotropic consequences of adaptation can influence the emergence of specialists or generalists, and are critical for evolution in temporally or spatially fluctuating environments. While many experiments have examined the pleiotropic effects of adaptation at a snapshot in time, very few have observed the dynamics by which these effects emerge and evolve. Here, we propagated hundreds of diploid and haploid laboratory budding yeast populations in each of three environments, and then assayed their fitness in multiple environments over 1000 generations of evolution. We find that replicate populations evolved in the same condition share common patterns of pleiotropic effects across other environments, which emerge within the first several hundred generations of evolution. However, we also find dynamic and environment-specific variability within these trends: variability in pleiotropic effects tends to increase over time, with the extent of variability depending on the evolution environment. These results suggest shifting and overlapping contributions of chance and contingency to the pleiotropic effects of adaptation, which could influence evolutionary trajectories in complex environments that fluctuate across space and time.

scholarly journals Climate and plant community diversity in space and time

2020 ◽  
Vol 117 (9) ◽  
pp. 4464-4470 ◽  
Author(s):  
Susan Harrison ◽  
Marko J. Spasojevic ◽  
Daijiang Li
Keyword(s):  
Plant Community ◽  
Plant Diversity ◽  
Phylogenetic Diversity ◽  
Spatial Scales ◽  
Community Diversity ◽  
Niche Conservatism ◽  
Space And Time ◽  
Drying Trend ◽  
Functional And Phylogenetic Diversity ◽  
Over Time

Climate strongly shapes plant diversity over large spatial scales, with relatively warm and wet (benign, productive) regions supporting greater numbers of species. Unresolved aspects of this relationship include what causes it, whether it permeates to community diversity at smaller spatial scales, whether it is accompanied by patterns in functional and phylogenetic diversity as some hypotheses predict, and whether it is paralleled by climate-driven changes in diversity over time. Here, studies of Californian plants are reviewed and new analyses are conducted to synthesize climate–diversity relationships in space and time. Across spatial scales and organizational levels, plant diversity is maximized in more productive (wetter) climates, and these consistent spatial relationships are mirrored in losses of taxonomic, functional, and phylogenetic diversity over time during a recent climatic drying trend. These results support the tolerance and climatic niche conservatism hypotheses for climate–diversity relationships, and suggest there is some predictability to future changes in diversity in water-limited climates.

scholarly journals Escherichia colipopulations adapt to complex, unpredictable fluctuations without any trade-offs across environments

2016 ◽  
Author(s):  
Shraddha Karve ◽  
Devika Bhave ◽  
Dhanashri Nevgi ◽  
Sutirth Dey
Keyword(s):  
Escherichia Coli ◽  
Growth Rate ◽  
Growth Rates ◽  
Complex Environments ◽  
Multiple Stresses ◽  
Trade Off ◽  
Trade Offs ◽  
Fluctuating Environments ◽  
Laboratory Populations ◽  
Lower Variation

AbstractIn nature, organisms are simultaneously exposed to multiple stresses (i.e. complex environments) that often fluctuate unpredictably. While both these factors have been studied in isolation, the interaction of the two remains poorly explored. To address this issue, we selected laboratory populations ofEscherichia coliunder complex (i.e. stressful combinations of pH, H2O2and NaCl) unpredictably fluctuating environments for ~900 generations. We compared the growth rates and the corresponding trade-off patterns of these populations to those that were selected under constant values of the component stresses (i.e. pH, H2O2and NaCl) for the same duration. The fluctuation-selected populations had greater mean growth rate and lower variation for growth rate over all the selection environments experienced. However, while the populations selected under constant stresses experienced severe tradeoffs in many of the environments other than those in which they were selected, the fluctuation-selected populations could by-pass the across-environment trade-offs completely. Interestingly, trade-offs were found between growth rates and carrying capacities. The results suggest that complexity and fluctuations can strongly affect the underlying trade-off structure in evolving populations.

scholarly journals Agri-food Exports and Challenges of Foreign Markets for a Small region: a Network Approach

2021 ◽  
Vol 17 (2) ◽  
pp. 607-618
Author(s):  
Roberta Sisto ◽  
Alba Marseglia ◽  
Edgardo Sica
Keyword(s):  
Small And Medium Enterprises ◽  
Research Question ◽  
Small Region ◽  
Complex Environments ◽  
Trade Patterns ◽  
Essential Condition ◽  
Eu Countries ◽  
Depth Analysis ◽  
Medium Enterprises ◽  
Over Time

Over the last decades, the agri-food sector has been involved in a substantial process of internationalisation. For many agri-food firms, internationalisation has become a significant element of competitiveness and an essential condition for their survival and success in spite of the possible initial difficulties in competing and organising activities in uncertain and complex environments. These challenges concern mainly agri-food small and medium enterprises (SMEs) that, due to their size, are in a more vulnerable position in relation to trade barriers compared to larger firms. Based on these premises, we investigated the structure of the agrifood exports of a small region by exploring its characteristics and evolution over time. While this research is relevant per sé, it can also explain the macroeconomic dynamics of the whole area and determine the further development of agri-food exports of a small region to non-EU countries. The analysis concentrates on exports to extra-EU countries from agri-food firms located in the province of Foggia (the south-east of Italy), a small area characterised by a large presence of SMEs and micro firms that are mainly devoted to agricultural production and food processing. To answer the research question, we employ the social network analysis, a method increasingly used for analysing international trade patterns. The use of this methodology has allowed us to conduct an in-depth analysis of firms and countries that occupy a strategic position in the network. These actors are crucial for the network’s survival since their removal could make the network more fragmented and disconnected. The analysis has been conducted in a dynamic way by exploring the characteristics of the network in 2014–2019, allowing us to assess its evolution over time. The results show that the structural properties of the analysed network have remarkably enhanced over time. However, the current network structure is not satisfactory yet since it relies, for the most part, on the connections among a few leading firms and a limited number of destination countries.

Annual dormancy cycles in Lesquerella fendleri (Brassicaceae) seeds stored under both field and laboratory conditions

2000 ◽  
Vol 77 (11) ◽  
pp. 1648-1654
Author(s):  
Laura A Hyatt ◽  
Ann S Evans ◽  
Carol C Baskin
Keyword(s):  
Seed Storage ◽  
Storage Conditions ◽  
Perennial Species ◽  
Lesquerella Fendleri ◽  
Laboratory Conditions ◽  
Fluctuating Environments ◽  
Growth Chambers ◽  
Field And Laboratory Conditions ◽  
Dormancy Cycles ◽  
Over Time

Patterns of germination over time were investigated in a short-lived desert perennial species, Lesquerella fendleri (Gray) S. Wats. Field-collected seeds were either buried in the field in cloth bags or stored in a glass jar under laboratory conditions. Regular germination tests were conducted under a range of alternating temperatures (buried seeds) or under differing water regimes (laboratory-stored seeds). Testing revealed Lesquerella fendleri to have an annual dormancy-nondormancy cycle, which was manifest regardless of seed storage conditions, suggesting that cycles may be partially endogenously regulated. Increasing seed germinability in field-stored seeds (maximum of 30% in year 1 and 95% in year 2) leads to the formation of a seed bank for at least 1 year and enhances the possibility of spreading germination events through time. This allows parent plants to maximize fitness in randomly fluctuating environments. The existence of two seedling flushes in the field and single germinability peaks in growth chambers suggests that dormancy cycling may support the formation of a metapopulation with subpopulations which are, although physically intermingled, genetically distinct.

scholarly journals Things Are Not Always What They Seem: The Origins and Evolution of Intragroup Conflict

2020 ◽  
pp. 000183922096518 ◽  
Author(s):  
Priti Pradhan Shah ◽  
Randall S. Peterson ◽  
Stephen L. Jones ◽  
Amanda J. Ferguson
Keyword(s):  
Social Networks ◽  
Qualitative Study ◽  
Team Performance ◽  
Task Conflict ◽  
Intragroup Conflict ◽  
Team Conflict ◽  
Student Teams ◽  
Evolutionary Trajectories ◽  
Or Team ◽  
Over Time

Teams scholars have historically conceptualized and measured intragroup conflict at the team level. But emerging evidence suggests that perceptions of intragroup conflict are often not uniform, shared, or static. These findings suggest important questions about the microfoundations of intragroup conflict: Where does conflict within teams originate? And how does it evolve over time? We address these and other questions in three abductive studies. We consider four origination points—an individual, dyad, subgroup, or team—and three evolutionary trajectories—conflict continuity, contagion, and concentration. Study 1, a qualitative study of narrative accounts, and Study 2, a longitudinal social networks study of student teams, reveal that fewer than 30 percent of teams experience team-level conflict. Instead, conflict more commonly originates and persists at individual, dyadic, or subgroup levels. Study 2 further demonstrates that traditional psychometric intragroup conflict scales mask the existence of these various origins and trajectories of conflict. Study 3, a field study of manufacturing teams, reveals that individual and dyadic task conflict origins positively predict team performance, whereas traditional intragroup task conflict measures negatively predict team performance. The results raise serious concerns about current methods and theory in the team conflict literature and suggest that researchers must go beyond team-level conceptualizations of conflict.

scholarly journals The importance of offshore origination revealed through ophiuroid phylogenomics

2017 ◽  
Vol 284 (1858) ◽  
pp. 20170160 ◽  
Author(s):  
Guadalupe Bribiesca-Contreras ◽  
Heroen Verbruggen ◽  
Andrew F. Hugall ◽  
Timothy D. O'Hara
Keyword(s):  
Deep Sea ◽  
Marine Invertebrates ◽  
Range Shift ◽  
Evolutionary Adaptation ◽  
Evolutionary Processes ◽  
Opposite Pattern ◽  
Bathymetric Range ◽  
Evolutionary Pattern ◽  
Transitional State ◽  
Over Time

Our knowledge of macro-evolutionary processes in the deep sea is poor, leading to much speculation about whether the deep sea is a source or sink of evolutionary adaptation. Here, we use a phylogenetic approach, on large molecular (688 species, 275 kbp) and distributional datasets (104 513 records) across an entire class of marine invertebrates (Ophiuroidea), to infer rates of bathymetric range shift over time between shallow and deep water biomes. Biome conservation is evident through the phylogeny, with the majority of species in most clades distributed within the same bathome. Despite this, bathymetric shifts have occurred. We inferred from ancestral reconstructions that eurybathic or intermediate distributions across both biomes were a transitional state and direct changes between shallow and deep sea did not occur. The macro-evolutionary pattern of bathome shift appeared to reflect micro-evolutionary processes of bathymetric speciation. Results suggest that most of the oldest clades have a deep-sea origin, but multiple colonization events indicate that the evolution of this group conforms neither to a simple onshore–offshore hypothesis, nor the opposite pattern. Both shallow and deep bathomes have played an important role in generating the current diversity of this major benthic class.

Melanism and ontogeny: a case study in lizards of the Liolaemus fitzingerii group (Squamata: Liolaemini)

2016 ◽  
Vol 94 (3) ◽  
pp. 199-206 ◽  
Author(s):  
P.C. Escudero ◽  
I. Minoli ◽  
M.A. González Marín ◽  
M. Morando ◽  
L.J. Avila
Keyword(s):  
New Species ◽  
Body Size ◽  
Comparative Studies ◽  
Species Group ◽  
Evolutionary Adaptation ◽  
Body Measurements ◽  
Adaptation Studies ◽  
Present Evidence ◽  
Over Time

Color polymorphisms in general and melanism in particular have been the focus of many evolutionary adaptation studies. In lizards of the genus Liolaemus Wiegmann, 1834, patterns of melanism have been poorly studied, although they have been used as diagnostic characters for identifying and describing new species. We investigated the relationships between melanism, body size, sex, and time in a population of Rawson Lizard (Liolaemus xanthoviridis Cei and Scolaro, 1980) with extensive ventral melanism. The study took place in Bahía Isla Escondida, Chubut (Argentina), during three summer seasons (2012 to 2014). We tagged each individual, recorded body measurements and sex, and took ventral photographs to estimate the proportion of melanism. Our results showed that ventral melanism increased over time as each individual increased its snout–vent length (SVL). Body size explained 44% of the variation in melanism and males were more melanistic than females. Previous comparative studies of lizards in this species group showed no relationship between melanism and different taxonomic units or with thermal functionality. Here, we present evidence suggesting that melanism might be a character with an ontogenetic origin that is strongly associated with sex and body size. This pattern could be shared among species of this group of lizards, and even more importantly, it may be related to variable selection forces occurring throughout ontogeny.

scholarly journals Skilled we-intentionality: Situating joint action in the living environment

2021 ◽  
Vol 1 ◽  
pp. 54
Author(s):  
Julian Kiverstein ◽  
Erik Rietveld
Keyword(s):  
Joint Action ◽  
Living Environment ◽  
Space And Time ◽  
Ways Of Thinking ◽  
Over Time

There is a difference between the activities of two or more individuals that are performed jointly such as playing music in a band or dancing as a couple, and performing these same activities alone. This difference is sometimes captured by appealing to shared or joint intentions that allow individuals to coordinate what they do over space and time. In what follows we will use the terminology of we-intentionality to refer to what individuals do when they engage in group ways of thinking, feeling and acting. Our aim in this paper is to argue that we-intentionality is best understood in relation to a shared living environment in which acting individuals are situated. By the “living environment” we mean to refer to places and everyday situations in which humans act. These places and situations are simultaneously social, cultural, material and natural. We will use the term “affordance” to refer to the possibilities for action the living environment furnishes. Affordances form and are maintained over time through the activities people repeatedly engage in the living environment. We will show how we-intentionality is best understood in relation to the affordances of the living environmentand by taking into account the skills people have to engage with these affordances. For this reason we coin the term ‘skilled we-intentionality’ to characterize the intentionality characteristic of group ways of acting, feeling and thinking.

scholarly journals THE VIRTUALIZATION OF CH FOR HISTORICAL RECONSTRUCTION: THE AR FRUITION OF THE FOUNTAIN OF ST. GEORGE SQUARE IN VALLETTA (MALTA)

2020 ◽  
Vol XLIV-4/W1-2020 ◽  
pp. 143-149
Author(s):  
A. Scianna ◽  
G. F. Gaglio ◽  
R. Grima ◽  
M. La Guardia
Keyword(s):  
Point Clouds ◽  
Archaeological Sites ◽  
Complex Environments ◽  
Historical Reconstruction ◽  
Space And Time ◽  
Laser Scanners ◽  
Dense Point ◽  
Study Case ◽  
The Right ◽  
Survey Methodologies

Abstract. Improving accessibility to Cultural Heritage (CH) is an increasingly urgent challenge today. It is not only a matter of physical inaccessibility but also temporal, considering that part of CH now lost. Fortunately, the most modern technological tools are helping to break down both space and time barriers. In facts, recent advances in representation, 3D modelling and survey methodologies opened new scenarios for valorization and conservation of CH. In particular, the improvement of quality in resolution and sensor sensitivity of cameras allowed to achieve the right level of 3D reconstruction through digital photogrammetry procedures. In the same field, terrestrial laser scanners (TLS) allowed acquiring dense point clouds of complex environments with a millimetric level of accuracy. At the same time, the application of Augmented Reality (AR) and Virtual Reality (VR) technologies is an excellent solution for improving the accessibility to monuments, museums and archaeological sites. It is possible to share new levels of information about CH, in space and time, for touristic, managerial and scientific aims. This work is focused on the virtualization of CH, considering the study case of the fountain of Wignacourt, today present in St. Philip Garden in Floriana and initially located in Valletta (Malta). The application presented allows the virtual fruition of the monument placed in its original location, St. George Square. A simplified plant of the square will enable tourists to make a temporal journey in the past with their mobile device. The work is part of the Interreg Italia-Malta European project named I-Access, dedicated to the improvement of CH accessibility. It focuses the attention to the experimentation of new specific procedures in Geomatics necessary to solve big data issues of complex environment visualization.

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