scholarly journals The Black Queen Hypothesis: Evolution of Dependencies through Adaptive Gene Loss

mBio ◽  
2012 ◽  
Vol 3 (2) ◽  
Author(s):  
J. Jeffrey Morris ◽  
Richard E. Lenski ◽  
Erik R. Zinser
Keyword(s):  
Public Goods ◽  
Gene Loss ◽  
Selective Advantage ◽  
Free Living ◽  
Microbial World ◽  
Individual Level ◽  
Novel Theory ◽  
Queen Of Spades ◽  
Living Organisms ◽  
The Individual

ABSTRACTReductive genomic evolution, driven by genetic drift, is common in endosymbiotic bacteria. Genome reduction is less common in free-living organisms, but it has occurred in the numerically dominant open-ocean bacterioplanktonProchlorococcusand “CandidatusPelagibacter,” and in these cases the reduction appears to be driven by natural selection rather than drift. Gene loss in free-living organisms may leave them dependent on cooccurring microbes for lost metabolic functions. We present the Black Queen Hypothesis (BQH), a novel theory of reductive evolution that explains how selection leads to such dependencies; its name refers to the queen of spades in the game Hearts, where the usual strategy is to avoid taking this card. Gene loss can provide a selective advantage by conserving an organism’s limiting resources, provided the gene’s function is dispensable. Many vital genetic functions are leaky, thereby unavoidably producing public goods that are available to the entire community. Such leaky functions are thus dispensable for individuals, provided they are not lost entirely from the community. The BQH predicts that the loss of a costly, leaky function is selectively favored at the individual level and will proceed until the production of public goods is just sufficient to support the equilibrium community; at that point, the benefit of any further loss would be offset by the cost. Evolution in accordance with the BQH thus generates “beneficiaries” of reduced genomic content that are dependent on leaky “helpers,” and it may explain the observed nonuniversality of prototrophy, stress resistance, and other cellular functions in the microbial world.

scholarly journals Explaining Cooperative Behavior in Public Goods Games: How Preferences and Beliefs Affect Contribution Levels

Games ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 15 ◽  
Author(s):  
Kurt Ackermann ◽  
Ryan Murphy
Keyword(s):  
Public Goods ◽  
Social Preferences ◽  
Cooperative Behavior ◽  
Large Body ◽  
Individual Choice ◽  
Endogenous Factors ◽  
Individual Level ◽  
Repeated Interaction ◽  
Public Goods Games ◽  
The Individual

There is a large body of evidence showing that a substantial proportion of people cooperate in public goods games, even if the situation is one-shot and completely anonymous. In the present study, we bring together two major endogenous factors that are known to affect cooperation levels, and in so doing replicate and extend previous empirical research on public goods problems in several important ways. We measure social preferences and concurrently elicit beliefs on the individual level using multiple methods, and at multiple times during the experiment. With this rich set of predictor variables at the individual level, we test how well individual contribution decisions can be accounted for in both a one-shot and a repeated interaction. We show that when heterogeneity in people’s preferences and beliefs is taken into consideration, more than 50% of the variance in individual choice behavior can be explained. Furthermore, we show that people do not only update their beliefs in a repeated public goods game, but also that their social preferences change, to some extent, in response to the choices of other decision makers.

Learning Agility

2021 ◽  
pp. 3-30
Author(s):  
Kenneth P. De Meuse ◽  
Veronica Schmidt Harvey
Keyword(s):  
Financial Performance ◽  
Psychological Contract ◽  
Deoxyribonucleic Acid ◽  
Organizational Health ◽  
First Century ◽  
Learning Agility ◽  
Individual Level ◽  
Living Organisms ◽  
The Individual ◽  
The Relationship

Learning Agility: The DNA for Leaders and Organizations in the Twenty-First Century highlights the importance of learning agility for identifying and developing the next generation of leaders. Similar to how DNA (deoxyribonucleic acid) carries the genetic instructions used in the functioning, growth, and reproduction of all living organisms, it can be argued that the selection and development of tomorrow’s leaders is the DNA responsible for the financial performance and organizational health of a company’s future. In the chapter, the need for “agility” at both the individual level and the company level is explored. Initially, the changing corporate landscape is examined and how the relationship between employees and employers (i.e., the psychological contract) has evolved is investigated. The emergence and expansion of the learning agility construct also are reviewed. Ultimately, the goal is to set the stage for a book devoted to assisting scholars and practitioners in their quest to understand and apply learning agility effectively.

Cross-Validation of Two Accelerometers for Assessment of Physical Activity and Sedentary Time in Preschool Children

2017 ◽  
Vol 29 (2) ◽  
pp. 268-277 ◽  
Author(s):  
Sofiya Alhassan ◽  
John R. Sirard ◽  
Laura B. F. Kurdziel ◽  
Samantha Merrigan ◽  
Cory Greever ◽  
...  
Keyword(s):  
Physical Activity ◽  
Mixed Model ◽  
Criterion Measure ◽  
Free Living ◽  
Type Method ◽  
Individual Level ◽  
Cut Point ◽  
Activity Intensity ◽  
The Individual ◽  
Low Sensitivity

Purpose:The purpose of this study was to cross-validate previously developed Actiwatch (AW; Ekblom et al. 2012) and AcitGraph (AG; Sirard et al. 2005; AG-P, Pate et al. 2006) cut-point equations to categorize free-living physical activity (PA) of preschoolers using direct observation (DO) as the criterion measure. A secondary aim was to compare output from the AW and the AG from previously developed equations.Methods:Participants’ (n = 33; age = 4.4 ± 0.8 yrs; females, n=12) PA was directly observed for three 10-min periods during the preschool-day while wearing the AW (nondominant wrist) and AG (waist). Device specific cut-points were used to reduce the AW-E (Ekblom et al. 2012) and AG (AG-S, Sirard et al. 2005; AG-P, Pate et al. 2006) data into intensity categories. Spearman correlations (rsp) and agreement statistics were used to assess associations between the DO intensity categories and device data. Mixed model regression was used to identify differences in times spent in activity intensity categories.Results:There was a significant correlation between AW and AG output across all data (rsp = 0.41, p < .0001) and both were associated with the DO intensity categories (AW: rsp = 0.47, AG: rsp = 0.47; p < .001). At the individual level, all devices demonstrated relatively low sensitivity but higher specificity. At the group level, AW-E and AG-P provided similar estimates of time spent in moderate-to-vigorous PA (MVPA, AW-E: 4.7 ± 4.1, AG-P: 4.4 ± 3.3), compared with DO (5.1 ± 3.5). Conclusion: The AW-E and AG-P estimated times spent in MVPA were similar to DO, but the weak agreement statistics indicate that neither device cut-point equations provided accurate estimates at the individual level.

scholarly journals Extreme Rituals as Social Technologies

2014 ◽  
Vol 14 (5) ◽  
pp. 345-355 ◽  
Author(s):  
Ronald Fischer ◽  
Dimitris Xygalatas
Keyword(s):  
Feedback Loop ◽  
Cultural Practices ◽  
Selective Advantage ◽  
Group Level ◽  
Physical Pain ◽  
Social Functions ◽  
Individual Level ◽  
The Social ◽  
Social Technologies ◽  
The Individual

We often think of pain as intrinsically bad, and the avoidance of pain is a fundamental evolutionary drive of all species. How can we then explain widespread cultural practices like certain rituals that involve the voluntary infliction of physical pain? In this paper, we argue that inflicting and experiencing pain in a ritual setting may serve important psychological and social functions. By providing psychological relief and leading to stronger identification with the group, such practices may result in a positive feedback loop, which serves both to increase the social cohesion of the community and the continuation of the ritual practices themselves. We argue that although the selective advantage of participation lies at the individual level, the benefits of those practices de facto extend to the group level, thereby allowing extreme rituals to function as effective social technologies.

scholarly journals Can mobile genetic elements rescue genes from extinction?

2020 ◽  
Vol 66 (6) ◽  
pp. 1069-1071
Author(s):  
Bram van Dijk
Keyword(s):  
Horizontal Gene Transfer ◽  
Microbial Population ◽  
Gene Loss ◽  
Mobile Genetic Elements ◽  
Sequence Evolution ◽  
Fitness Effect ◽  
Microbial World ◽  
Genetic Elements ◽  
Rapid Changes ◽  
The Individual

Abstract Bacteria and other prokaryotes evolve primarily through rapid changes in their gene content by quickly losing and gaining genes whenever an ecological opportunity emerges. As gene loss and horizontal gene transfer (HGT) appear to be the most common events across the prokaryotic tree of life, we need to think beyond gradual sequence evolution if we wish to understand the microbial world. Especially genes that reside on mobile genetic elements (MGEs) may spread much more rapidly through a microbial population than genes that reside on the bacterial chromosome. This raises the question: why are some genes associated with MGEs, while others are not? Here, I briefly review a recently proposed class of genes for which we have coined the term “rescuable genes”. The fitness effect of carrying these genes is so small, either constantly or on average, that they are prone to be lost from a microbial population. I argue that HGT, even when costly to the individual cells, may play an important role in maintaining these rescuable genes in microbial communities.

scholarly journals A data-driven method for reconstructing and modelling social interactions in moving animal groups

2020 ◽  
Vol 375 (1807) ◽  
pp. 20190380 ◽  
Author(s):  
R. Escobedo ◽  
V. Lecheval ◽  
V. Papaspyros ◽  
F. Bonnet ◽  
F. Mondada ◽  
...  
Keyword(s):  
Social Interactions ◽  
Social Systems ◽  
Quantitative Description ◽  
Group Living ◽  
Quantitative Model ◽  
Individual Level ◽  
Wide Range ◽  
Living Organisms ◽  
Individual Scale ◽  
The Individual

Group-living organisms that collectively migrate range from cells and bacteria to human crowds, and include swarms of insects, schools of fish, and flocks of birds or ungulates. Unveiling the behavioural and cognitive mechanisms by which these groups coordinate their movements is a challenging task. These mechanisms take place at the individual scale and can be described as a combination of interactions between individuals and interactions between these individuals and the physical obstacles in the environment. Thanks to the development of novel tracking techniques that provide large and accurate datasets, the main characteristics of individual and collective behavioural patterns can be quantified with an unprecedented level of precision. However, in a large number of studies, social interactions are usually described by force map methods that only have a limited capacity of explanation and prediction, being rarely suitable for a direct implementation in a concise and explicit mathematical model. Here, we present a general method to extract the interactions between individuals that are involved in the coordination of collective movements in groups of organisms. We then apply this method to characterize social interactions in two species of shoaling fish, the rummy-nose tetra ( Hemigrammus rhodostomus ) and the zebrafish ( Danio rerio ), which both present a burst-and-coast motion. From the detailed quantitative description of individual-level interactions, it is thus possible to develop a quantitative model of the emergent dynamics observed at the group level, whose predictions can be checked against experimental results. This method can be applied to a wide range of biological and social systems. This article is part of the theme issue ‘Multi-scale analysis and modelling of collective migration in biological systems’.

scholarly journals A data-driven method for reconstructing and modelling social interactions in moving animal groups

2019 ◽  
Author(s):  
R. Escobedo ◽  
V. Lecheval ◽  
V. Papaspyros ◽  
F. Bonnet ◽  
F. Mondada ◽  
...  
Keyword(s):  
Social Interactions ◽  
Social Systems ◽  
Quantitative Description ◽  
Group Living ◽  
Data Sets ◽  
Individual Level ◽  
Wide Range ◽  
Living Organisms ◽  
Individual Scale ◽  
The Individual

AbstractGroup-living organisms that collectively migrate range from cells and bacteria to human crowds, and include swarms of insects, schools of fish and flocks of birds or ungulates. Unveiling the behavioural and cognitive mechanisms by which these groups coordinate their movements is a challenging task. These mechanisms take place at the individual scale and they can be described as a combination of pairwise interactions between individuals and interactions between these individuals and the physical obstacles in the environment. Thanks to the development of novel tracking techniques that provide large and accurate data sets, the main characteristics of individual and collective behavioural patterns can be quantified with an unprecedented level of precision. However, in a large number of works, social interactions are usually described by force map methods that only have a limited capacity of explanation and prediction, being rarely suitable for a direct implementation in a concise and explicit mathematical model. Here, we present a general method to extract the interactions between individuals that are involved in the coordination of collective movements in groups of organisms. We then apply this method to characterize social interactions in two species of shoaling fish, the rummynose tetra (Hemigrammus rhodostomus) and the zebrafish (Danio rerio), which both present a burst-and-coast motion. The detailed quantitative description of microscopic individual-level interactions thus provides predictive models of the emergent dynamics observed at the macroscopic group-level. This method can be applied to a wide range of biological and social systems.

scholarly journals Selfishness driving reductive evolution shapes interdependent patterns in spatially structured microbial communities

2020 ◽  
Author(s):  
Miaoxiao Wang ◽  
Xiaonan Liu ◽  
Yong Nie ◽  
Xiao-Lei Wu
Keyword(s):  
Public Goods ◽  
Reductive Evolution ◽  
Individual Level ◽  
Function Loss ◽  
Evolution Dynamics ◽  
New Perspective ◽  
Public Production ◽  
The Individual ◽  
Spatial Positioning ◽  
And Function

AbstractMicrobes release a wide variety of metabolites to the environment that benefit the whole population, called public goods. Public goods sharing drives adaptive function loss, and allows the rise of metabolic cross-feeding. However, how public goods sharing governs the succession of communities over evolutionary time scales remains unclear. To resolve this issue, we constructed an individual-based model, where an autonomous population that possessed functions to produce three essential public goods, was allowed to randomly lose functions. Simulations revealed that function loss genotypes could evolve from the autonomous ancestor, driven by the selfish public production trade-off at the individual level. These genotypes could then automatically develop to three possible types of interdependent patterns: complete functional division, one-way dependency, and asymmetric functional complementation, which were influenced by function cost and function redundancy. In addition, we found random evolutionary events, i.e., the priority and the relative spatial positioning of genotype emergence, are also important in governing community assembly. Moreover, communities occupied by interdependent patterns exhibited better resistance to environmental perturbation, suggesting such patterns are selectively favored. Our work integrates ecological interactions with evolution dynamics, providing a new perspective to explain how reductive evolution shapes microbial interdependencies and governs the succession of communities.

Differential Effects of Competence and Morality on Self-Esteem at the Individual and the Collective Level

2020 ◽  
Vol 51 (3) ◽  
pp. 183-198
Author(s):  
Wiktor Soral ◽  
Mirosław Kofta
Keyword(s):  
Self Esteem ◽  
Differential Effects ◽  
Individual Level ◽  
The Subject ◽  
The Individual

Abstract. The importance of various trait dimensions explaining positive global self-esteem has been the subject of numerous studies. While some have provided support for the importance of agency, others have highlighted the importance of communion. This discrepancy can be explained, if one takes into account that people define and value their self both in individual and in collective terms. Two studies ( N = 367 and N = 263) examined the extent to which competence (an aspect of agency), morality, and sociability (the aspects of communion) promote high self-esteem at the individual and the collective level. In both studies, competence was the strongest predictor of self-esteem at the individual level, whereas morality was the strongest predictor of self-esteem at the collective level.

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