In evolutionary biology and ecology, ontological and epistemological perspectives based on the replicator and the interactor have become the background that makes it possible to transcend traditional biological levels of organization and to achieve a unified view of evolution in which replication and interaction are fundamental operating processes. Using the transactional perspective proposed originally by John Dewey and Arthur Fisher Bentley, a new ontological and methodological category is proposed here: the transactor. The transactional perspective, based on the concept of the (...) transactor, bridges the dichotomy between organisms and environment that characterizes the interactional perspective on evolution and provides epistemological support for the emergentist, systemic view of evolutionary and developmental processes. (shrink)

Understanding community-level selection using Lewontin’s criteria requires both community-level inheritance and community-level heritability, and in the discipline of community and ecosystem genetics, these are often conflated. While there are existing studies that show the possibility of both, these studies impose community-level inheritance as a product of the experimental design. For this reason, these experiments provide only weak support for the existence of community-level selection in nature. By contrast, treating communities as interactors (in line with Hull’s replicator-interactor framework or Dawkins’s (...) idea of the “extended phenotype”) provides a more plausible and empirically supportable model for the role of ecological communities in the evolutionary process. (shrink)

Genes are thought to have evolved from long-lived and multiply-interactive molecules in the early stages of the origins of life. However, at that stage there were no replicators, and the distinction between interactors and replicators did not yet apply. Nevertheless, the process of evolution that proceeded from initial autocatalytic hypercycles to full organisms was a Darwinian process of selection of favourable variants. We distinguish therefore between Neo-Darwinian evolution and the related Weismannian and Central Dogma divisions, on the one hand, (...) and the more generic category of Darwinian evolution on the other. We argue that Hull’s and Dawkins’ replicator/interactor distinction of entities is a sufficient, but not necessary, condition for Darwinian evolution to take place. We conceive the origin of genes as a separation between different types of molecules in a thermodynamic state space, and employ a notion of reproducers. (shrink)

Here we endorse Hull’s replicator/interactor framework as providing the overarching understanding sought by MacCord and Maienschein. We suggest that difficulties in seeing the regeneration of limbs by salamanders and of forest ecosystems after fires as similar evolutionary processes can be overcome in this framework. In generalizing Dawkins’s “selfish gene” perspective, Hull defined natural selection as “a process in which the differential extinction and proliferation of interactors causes the differential perpetuation of the replicators that produced them”. Although genes and bacteria (...) are simultaneously both replicators and interactors, communities and ecosystems are generally only interactors. As reproducers, members of sexual species are intermediate. Within such species, organisms are indeed the interactors whose “differential extinction and proliferation” causes the “differential perpetuation” of replicators. But sexually-reproducing organisms do not individually replicate, persist, or recur as interactors, and in consequence it is only those genes causing an interactor differential that are specifically perpetuated in the long run. Higher-level interactors may seldom if ever reproduce, but their recurrence does enable the “differential perpetuation” of replicators specifically responsible for their “differential extinction and proliferation”. In offering answers to the question “What are the replicators specifically responsible for the differential extinction and proliferation of such higher-level entities?” we hope to unify adaptive regeneration across scales, from organisms to ecosystems. (shrink)

Diverse living systems possess the capacity for regeneration; that is, they can under some circumstances repair, re-produce, and maintain themselves in the face of disturbance or damage. Think of systems as diverse as forests, microbial biofilms, corals, salamanders, hydra, and human skin cells. This capacity is fundamental to life—without it, many biological systems would be too fragile to cope with stress and would frequently collapse—but because it is multiply realized in wildly different living systems at many scales, finding a common (...) understanding may seem futile, and in fact research has proceeded along independent lines. For example, the sciences of organismal regeneration and ecological regeneration appear to have little more than a nominal relationship. Progress towards unification can be made, we think, by turning to evolutionary theory, specifically by synthesizing recent discussions of the evolution of individuals versus collectives with older literature about replicators versus interactors. This allows us to provide a partial answer in response to MacCord and Maienschein’s call for “basic units and mechanisms” of regeneration, relevant when that process is “adaptive.” We argue that the basics of adaptive regeneration can be understood and generalized through a modification of David Hull’s replicator-interactor framework. (shrink)

This paper evaluates and criticises the developmental systems conception of evolution and develops instead an extension of the gene's eye conception of evolution. We argue (i) Dawkin's attempt to segregate developmental and evolutionary issues about genes is unsatisfactory. On plausible views of development it is arbitrary to single out genes as the units of selection. (ii) The genotype does not carry information about the phenotype in any way that distinguishes the role of the genes in development from that other factors. (...) (iii) There is no simple and general causal criterion which distinguishes the role of genes in development and evolution. (iv) There is, however, an important sense in which genes but not every other developmental factor represent the phenotype. (v) The idea that genes represent features of the phenotype forces us to recognise that genes are not the only, or almost the only, replicators. Many mechanisms of replication are involved in both development and evolution. (vi) A conception of evolutionary history which recognises both genetic and non-genetic replicators, lineages of replicators and interactors has advantages over both the radical rejection of the replicator/interactor distinction and the conservative restriction of replication to genetic replication. (shrink)

In an earlier article published in this journal I challenge Reydon and Scholz’s (2009) claim that Organizational Ecology is a non-Darwinian program. In this reply to Reydon and Scholz’s subsequent response, I clarify the difference between our two approaches denoted by an emphasis here on the careful application of core Darwinian principles and an insistence by Reydon and Scholz on direct biological analogies. On a substantive issue, they identify as being the principal problem for Organizational Ecology, namely, the inability to (...) identify replicators and interactors “ of the right sort” in the business domain; this is also shown to be easily addressed with reference to empirical studies of business populations. (shrink)

In an earlier article published in this journal I challenge Reydon and Scholz’s (2009) claim that Organizational Ecology is a non-Darwinian program. In this reply to Reydon and Scholz’s subsequent response, I clarify the difference between our two approaches denoted by an emphasis here on the careful application of core Darwinian principles and an insistence by Reydon and Scholz on direct biological analogies. On a substantive issue, they identify as being the principal problem for Organizational Ecology, namely, the inability to (...) identify replicators and interactors “ of the right sort” in the business domain; this is also shown to be easily addressed with reference to empirical studies of business populations. (shrink)

This paper examines David Hull’s and Peter Godfrey-Smith’s accounts of biological individuality using the case of biofilms. Biofilms fail standard criteria for individuality, such as having reproductive bottlenecks and forming parent-offspring lineages. Nevertheless, biofilms are good candidates for individuals. The nature of biofilms shows that Godfrey-Smith’s account of individuality, with its reliance on reproduction, is too restrictive. Hull’s interactor notion of individuality better captures biofilms, and we argue that it offers a better account of biological individuality. However, Hull’s notion of (...) interactor needs more precision. We suggest some ways to make Hull’s notion of interactor and his account of individuality more precise. Generally, we maintain that biofilms are a good test case for theories of individuality, and a careful examination of biofilms furthers our understanding of biological individuality. (shrink)

In this paper I consider the view that scientific change is the result of a selection process which has the same structure as that which drives natural selection. I argue that there are important differences between organic evolution and scientific growth. First, natural selection is much more constrained than scientific change; for example it is hard to populations of organisms to escape local maxima. Science progresses; it may not even make sense to say that biological evolution is progressive. Second, natural (...) selection depends for its power on the specifics of its domain, so I doubt that there is much point in seeing a selective regime in science as an instance of a more general family of selective regimes. Third, the replicator/interactor distinction fits scientific change much less well than biological evolution. But a family of selective theories of science can be identified ranging from the very ambitious to the very modest. Though the very ambitious programs of evolutionary epistemology are in trouble, there is space for one which is not a trivial redescription of what everyone already knows, but which is sensitive to the peculiarities of its domain. That selective theory explains important aspects of the community organization of science, an organization which is central to scientific progress. (shrink)

In spite of the remarkable progress made in the burgeoning field of social neuroscience, the neural mechanisms that underlie social encounters are only beginning to be studied and could —paradoxically— be seen as representing the ‘dark matter’ of social neuroscience. Recent conceptual and empirical developments consistently indicate the need for investigations, which allow the study of real-time social encounters in a truly interactive manner. This suggestion is based on the premise that social cognition is fundamentally different when we are in (...) interaction with others rather than merely observing them. In this article, we outline the theoretical conception of a second-person approach to other minds and review evidence from neuroimaging, psychophysiological studies and related fields to argue for the development of a second-person neuroscience, which will help neuroscience to really go social; this may also be relevant for our understanding of psychiatric disorders construed as disorders of social cognition. (shrink)

The history and theoretical role of the concept of a ``replicator''is discussed, starting with Dawkins' and Hull's classic treatmentsand working forward. I argue that the replicator concept is still auseful one for evolutionary theory, but it should be revised insome ways. The most important revision is the recognition that notall processes of evolution by natural selection require thatsomething play the role of a replicator.

Two major clarifications have greatly abetted the understanding and fruitful expansion of the theory of natural selection in recent years: the acknowledgment that interactors, not replicators, constitute the causal unit of selection; and the recognition that interactors are Darwinian individuals, and that such individuals exist with potency at several levels of organization (genes, organisms, demes, and species in particular), thus engendering a rich hierarchical theory of selection in contrast with Darwin’s own emphasis on the organismic level. But a (...) piece of the argument has been missing, and individuals at levels distinct from organisms have been denied potency (although granted existence within the undeniable logic of the theory), because they do not achieve individuality with the same devices used by organisms and therefore seem weak by comparison. We show here that different features define Darwinian individuality across scales of size and time. In particular, species-individuals may develop few emergent features as direct adaptations. The interactor approach works with emergent fitnesses, not with emergent features; and species, as a consequence of their different mechanism for achieving individuality (reproductive exclusivity among subparts, that is, among organisms), express many effects from other levels. Organisms, by contrast, suppress upwardly cascading effects, because the organismic style of individuality (by functional integration of subparts) does not permit much competition or differential reproduction of parts from within. Species do not suppress the operation of lower levels; such effects therefore become available as exaptations conferring emergent fitness—a primary source of the different strength that species achieve as effective Darwinian individuals in evolution. (shrink)

Holobionts, consisting of a host and diverse microbial symbionts, function as distinct biological entities anatomically, metabolically, immunologically, and developmentally. Symbionts can be transmitted from parent to offspring by a variety of vertical and horizontal methods. Holobionts can be considered levels of selection in evolution because they are well-defined interactors, replicators/reproducers, and manifestors of adaptation. An initial mathematical model is presented to help understand how holobionts evolve. The model offered combines the processes of horizontal symbiont transfer, within-host symbiont proliferation, vertical (...) symbiont transmission, and holobiont selection. The model offers equations for the population dynamics and evolution of holobionts whose hologenomes differ in gene copy number, not in allelic or loci identity. The model may readily be extended to include variation among holobionts in the gene identities of both symbionts and host. (shrink)

Hierarchical organization is an essential characteristic of living things. Although most biologists affirm the concept of living things as hierarchically organized structures, there are widespread differences of interpretation in the meaning of hierarchy and of how the concept of hierarchy applies to living things. One such basic difference involves the distinction between the concept of control hierarchy and classification hierarchy. It is suggested that control hierarchies are distinguished from classification hierarchies in that while the former involve authority relationships between levels, (...) the latter do not. This is illustrated in an analysis of proposed hierarchies of replicators and interactors.The analysis of levels of hierarchies and their relationships also brings up the part-whole problem. An authority relationship between levels implies that the whole has a determining influence on the parts that make up the whole, and that parts have no independent, meaningful existence apart from the whole. The concept of an authority relationship in a part-whole relationship introduces the question of the independence or sovereignty of the components of the subordinate levels in a hierarchically organized living thing. This problem is discussed along with an analysis of the rather novel theory of enkapsis proposed by H. Dooyeweerd, in which he distinguishes part-whole relationships from enkaptic relationships. (shrink)

Enactivists often defend the following two claims: Successful interactions are not driven and explained by the interactors’ ability to mindread. And the mechanisms enabling 2nd personal social cognition and those enabling 3rd personal social cognition are distinct. In this paper, I argue that both of these claims are false. With regard to I argue that enactivists fail to provide a plausible alternative to traditional accounts of social cognition in interaction. I examine and reject Hanne De Jaegher’s view according to (...) which interaction is “constitutive” for social interaction. Furthermore, I critically discuss Shaun Gallagher’s and Daniel Hutto’s views according to which social interactions are exclusively driven by low level cognitive mechanisms such as “gaze following” and “emotion detection”. Concerning, I rely on data from so called “spontaneous response” false belief tasks to show that interactive and observational paradigms require the same “social-cognitive” interpretation. (shrink)

We present an account of semantics that is not construed as a mapping of language to the world but rather as a mapping between individual meaning spaces. The meanings of linguistic entities are established via a “meeting of minds.” The concepts in the minds of communicating individuals are modeled as convex regions in conceptual spaces. We outline a mathematical framework, based on fixpoints in continuous mappings between conceptual spaces, that can be used to model such a semantics. If concepts are (...) convex, it will in general be possible for interactors to agree on joint meaning even if they start out from different representational spaces. Language is discrete, while mental representations tend to be continuous—posing a seeming paradox. We show that the convexity assumption allows us to address this problem. Using examples, we further show that our approach helps explain the semantic processes involved in the composition of expressions. (shrink)

I consider two attempts to combine realism with pluralism about the units of selection: Sober and Wilson’s combination of “model” and “unit” pluralism, and Sterelny and Griffiths’ “local pluralism”. I argue that both of these attempts fail to show that realism and pluralism are compatible. Sober and Wilson’s pluralism turns out, on closer inspection, to be a kind of monism in disguise, while Sterelny and Griffiths’ local pluralism involves a combination of realism and anti-realism about interactors, and the units (...) of selection, that is fundamentally unstable. My conclusion is that one must choose whether to be a realist or a pluralist in this area: one cannot be both. The question of which we should choose is a further question that I do not take a stand on. (shrink)

Building upon a non-standard understanding of evolutionary process focusing on variation and persistence, I will argue that communities and ecosystems can evolve by natural selection as emergent individuals. Evolutionary biology has relied ever increasingly on the modeling of population dynamics. Most have taken for granted that we all agree on what is a population. Recent work has reexamined this perceived consensus. I will argue that there are good reasons to restrict the term “population” to collections of monophyletically related replicators and (...) interactors, which explains why many existing models in population biology exclude by definition many genuine evolving biological individuals such as communities and ecosystems. By studying a case of community evolution, we will see that it is variation that is important to evolutionary processes, not populations. Variation within a population is only one of many types of variation that can lead to evolution by natural selection. The upshot of focusing on variation is that cases of community and ecosystem adaptive change become tractable in evolutionary terms. I will show that complex emergent individuals such as communities and ecosystems cannot be fully accommodated by conventional population/reproduction models but can be accommodated by variation/persistence models. (shrink)

De Jaegher’s (2009) paper argues that Gallagher, who aims to replace traditional theory-of-mind accounts of social understanding with accounts based on direct perception (hereafter DP), has missed an important opportunity. Despite a desire to break faith with tradition, there is a danger that proponents of DP accounts will remain (at least tacitly) committed to an unchallenged, and perhaps unnoticed, sort of individualism inherent in traditional theories (i.e. those that regard our engagement with others as a ‘problem’ to be solved: a (...) problem of other minds). Taking a more root and branch approach, De Jaegher recommends a complete shift of focus. She proposes that a more thoroughgoing and fruitful response to traditional approaches must attend to, and seek to understand, interactional phenomena proper—for it is the nature of interactions themselves that importantly influence individuals. Hence, it is the processes of interacting which ‘span individuals’ and their specific, dynamic evolution over time that should take pride of place in research into social cognition. De Jaegher wants to put interactional processes – those that can ‘take on life of their own’ and ‘influence interactors’ – at the heart of enquiries into intersubjectivity. Citing other recent work she has done with Di Paolo, she bills this as ‘‘the central task of any account of intersubjectivity” (De Jaegher, 2009, p. 2; De Jaegher & Di Paolo, 2007). The trouble is that this way of putting matters can make it look as if there is just one task facing researchers in this area; that we are faced with an either/or choice. But it is clear that any fully illuminated understanding of interactional phenomena will require accounts of what individuals and their sub-personal processes/mechanisms are doing in this larger process and, presumably, how their mechanisms/tendencies of response constrain and shape local bouts of interacting, even if we assume it is the dynamics of such encounters that importantly influence and shape what comes next.. (shrink)

Reydon and Scholz raise doubts about the Darwinian status of organizational ecology by arguing that Darwinian principles are not applicable to organizational populations. Although their critique of organizational ecology’s typological essentialism is correct, they go on to reject the Darwinian status of organizational populations. This paper claims that the replicator-interactor distinction raised in modern philosophy of biology but overlooked for discussion by Reydon and Scholz provides a way forward. It is possible to conceptualize evolving Darwinian populations providing that the inheritance (...) mechanism is appropriately specified. By this approach, adaptation and selection are no longer dichotomized, and the evolutionary significance of knowledge transmission is highlighted. (shrink)

This article presents research on assemblages among humans and computational systems in which physical and virtual autonomous processes occur in order to create artworks allowing the emergence of mixed sensory set-ups. It begins with triadic relationships computer, physical objects and participants aimed at co-relations among bands of bots (virtual and physical) with groups of humans (interactors). The bots have a representation of the virtual world: physical bots live on a flat surface (Abbot 1991), a projection of the 3D environment (...) where the virtual bots live. The artwork also explores the metaphor of higher dimensions being understood through their projections in lower dimensions. Its goal is to weave interaction and autonomous processes, looking for poetic results integrating art, science and technology; results with aesthetic, poetic and functional qualities; and results exploring emergency and agency for design, construction and set-up of expressive systems. For these symbioses to happen the assemblage of environments with aesthetic and poetic appeal leads one to think about mixed cognitive processes that provoke emergent behaviours. I am interested in the behaviours emerged in such inter-relationships. Therefore, to achieve this goal, I have created a Java framework that allows me to program interfaces weaving such behaviors1 and also I have programmed a set of sketches using Processing2 to test the hypothesis. The main inquiries of such research are as follows: What kind of artwork could mix people with autonomous computational processes without becoming invasive? and Is such a dichotomy possible? To answer these questions, I came up with the idea of playing with swarms and flock algorithms mixing virtual and physical domains. Will this create the mixed behaviour I am looking for? Will the participants contribute with their actions, emotions and affects while the computer develops its own autonomous processes? (shrink)

The theory of evolution is supported by the theory of genetics, which provides a single causal mechanism to explain the activities of replicators and interactors. A common misrepresentation of the theory of evolution, however, is that interaction (involving interactors), and transmission (involving replicators), are distinct causal processes. Sandra Mitchell (1987) is misled by this. I discuss why only a single causal mechanism is working in evolution and why it is sufficient. Further, I argue that Mitchell's mistaken view of (...) the causal mechanism in evolution prevents her from resolving the conflict between Dawkins and Brandon. I conclude that the unit-of-selection question remains very much alive. (shrink)

Minichromosome maintenance (Mcm) proteins are well‐known for their functions in DNA replication. However, their roles in chromosome segregation are yet to be reviewed in detail. Following the discovery in 1984, a group of Mcm proteins, known as the ARS‐nonspecific group consisting of Mcm13, Mcm16‐19, and Mcm21‐22, were characterized as bonafide kinetochore proteins and were shown to play significant roles in the kinetochore assembly and high‐fidelity chromosome segregation. This review focuses on the structure, function, and evolution of this group of Mcm (...) proteins. Our in silico analysis of the physical interactors of these proteins reveals that they share non‐overlapping functions despite being copurified in biochemically stable complexes. We have discussed the contrasting results reported in the literature and experimental strategies to address them. Taken together, this review focuses on the structure‐function of the ARS‐nonspecific Mcm proteins and their evolutionary flexibility to maintain genome stability in various organisms. (shrink)

Digital artifacts from iPads to databases pervade our lives, and the design decisions that shape them affect how we think, act, communicate, and understand the world. But the pace of change has been so rapid that technical innovation is outstripping design. Interactors are often mystified and frustrated by their enticing but confusing new devices; meanwhile, product design teams struggle to articulate shared and enduring design goals. With Inventing the Medium, Janet Murray provides a unified vocabulary and a common methodology (...) for the design of digital objects and environments. It will be an essential guide for both students and practitioners in this evolving field. Murray explains that innovative interaction designers should think of all objects made with bits--whether games or Web pages, robots or the latest killer apps--as belonging to a single new medium: the digital medium. Designers can speed the process of useful and lasting innovation by focusing on the collective cultural task of inventing this new medium. Exploring strategies for maximizing the expressive power of digital artifacts, Murray identifies and examines four representational affordances of digital environments that provide the core palette for designers across applications: computational procedures, user participation, navigable space, and encyclopedic capacity. Each chapter includes a set of Design Explorations--creative exercises for students and thought experiments for practitioners--that allow readers to apply the ideas in the chapter to particular design problems. Inventing the Medium also provides more than 200 illustrations of specific design strategies drawn from multiple genres and platforms and a glossary of design concepts. (shrink)

In this paper it is argued that much can be gained for the analysis and evaluation of arguing when fallacies are not, or not only, conceived of as flawed premise–conclusion complexes but rather as argumentative moves which distort harmfully an interaction aiming at resolving communication problems argumentatively. Starting from Normative Pragmatics and the pragma-dialectical concept of fallacy, a case study is presented to illustrate a fallacy which is termed the 'revelation argument' because it is characterized by an interactor's revealing her (...) thoughts and/or emotions to the addressees and claiming that these would have justificatory or refutatory potential with respect to the problem discussed. Although the revelation argument may not be a paradigm case of resolution- hindering moves, it is an extreme case of flawed reasoning that illustrates plainly the advantages of a communicational perspective on arguing and fallacies. (shrink)

'Unit of selection' is a polysemic expression, meaning interactor, replicator/reproducer or manifestor of adaptation/type-1 agent in today's biological research. This Element presents each of these concepts and demonstrates the necessity of their isolation.

This paper argues that a plant together with the symbiotic fungus attached to its roots, a mycorrhizal collective, is an evolutionary individual, and further, that mycorrhizal individuality has important implications for evolutionary theory. Theoretical individuation is defended and then employed to show that mycorrhizal collectives function as interactors according to David Hull’s replicator-interactor model of evolution by natural selection, and because they have the potential to engage in pseudo-vertical transmission, mycorrhizal collectives also function as Darwinian individuals, according to Peter (...) Godfrey-Smith’s Darwinian Populations model of evolution by natural selection. Mycorrhizae in nature usually connect the roots of multiple plants, so mycorrhizal individuality entails the existence of overlapping evolutionary individuals, and because the potential to engage in pseudo-vertical transmission comes in degrees, it follows that these overlapping evolutionary individuals also come in degrees. I suggest here that the degree of evolutionary individuality in a symbiotic collective corresponds to its probability of reproducing with vertical or pseudo-vertical transmission. This probability constitutes a fourth parameter of graded Darwinian individuality in collective reproducers and warrants an update to Godfrey-Smith’s 3D model. (shrink)

This paper introduces the reconstitutor as a comprehensive unit of heredity within the context of evolutionary research. A reconstitutor is the structure resulting from a set of relationships between different elements or processes that are actively involved in the recreation of a specific phenotypic variant in each generation regardless of the biomolecular basis of the elements or whether they stand in a continuous line of ancestry. Firstly, we justify the necessity of introducing the reconstitutor by showing the limitations of other (...) evolutionary conceptions of the unit of heredity, such as the replicator, the reproducer, and the Darwinian individual. We argue that these conceptions are based on the requirement of lineage formation, which we argue to be unnecessary for the existence of evolutionary heredity. In the second part, we introduce the reconstitutor, which we base on the concept of Stability of Traits, and illustrate how it covers cases of hereditary phenomena not covered by the previous accounts. Secondly, we illustrate how the reconstitutor could serve as a platform to rethink ecological inheritance and other forms of inheritance that have been recently introduced under the song/singer model of evolution. (shrink)

This article proposes two conditions to assess whether an entity at a level of description is a unit of selection qua interactor. These two conditions make it possible to (1) distinguish biologically relevant entities from arbitrary ones and (2) distinguish units that can _potentially_ enter a selection process from those that have already done so. I show that the classical approaches used in the literature on units and levels of selection do not fare well with respect to either or both (...) of these desiderata. (shrink)

Considers the paradox of demonstrative retreat from public life, as illustrated by scenes like Sen. Ep. 78.20f. and Epict. 3.22.23 with ailing philosophers almost scurrilously eager to display their heroism. Why would a philosopher want to withdraw and, at the same time, make a show of his withdrawal? How can this kind of exemplarity fulfill its therapeutic function? And how is this kind of communication, with one’s back turned to the audience, as it were, supposed to work? Tacitus’ narrative of (...) Thrasea Paetus’ end in the Annales (16.22ff.) is analyzed as illustrating this form of communication and compared with a similar communication strategy of Seneca’s Epistulae morales as a document of exemplary withdrawal. Concentric circles of audiences and interactors are layered around the role model, and he reader is pulled into the center of the circle, into direct contact with the exemplum. The way in which this happens determines the reader’s role in the story and thus the import the role model. (shrink)

The yeast two‐hybrid system is a genetic method that detects protein‐protein interactions. One application is the detection by library screening of new interactors of a protein of known function. In the August issue of Nature Genetics, Fromont‐Racine et al.1 showed for the first time that the construction of the protein interaction map of a complex pathway, such as that of the mRNA splicing machinery, is now possible, because of the combination of recent technical improvements elaborated in several laboratories. With (...) a yeast cell mating procedure that increases screen efficiency, they used their complex yeast genomic library of 5 × 106 clones to test 700 × 106 interactions against 15 proteins. They identified and classified 170 potential interactors, including approximately 70 proteins of previously unknown function. More than 25% of the interactors are probably biologically relevant. The achievements of Fromont‐Racine et al. have opened the way to the systematic analysis of the protein interaction networks of the 6,000 open reading frames‐yeast proteome. This task requires, however, automation of the library screens and creation of a two‐hybrid library database. BioEssays 20:1–5, 1998. © 1998 John Wiley & Sons, Inc. (shrink)

G. H. Mead developed an alternative "metaphysics" of selfhood and agency that underlies, but is seldom made explicit in discussions of, his social developmental psychology. This is an alternative metaphysics that rejects any pregiven, fixed foundations for being and knowing. It assumes the emergence of social psychological phenomena such as mind, self, and deliberative agency through the activity of human actors and interactors within their biophysical and sociocultural world. Of central importance to the emergence of self-consciousness and deliberative forms (...) of human agency is the ability of developing individuals to take the perspectives of others within their own conduct. However, precisely what is involved in this process, and whether or not it assumes the preexistence of exactly those forms of selfhood and agency, the emergence of which it seeks to explain, have been much disputed. In this essay, recent reinterpretations of Mead's "metaphysics" are used to argue that his overall theoretical program contains resources necessary to overcome charges of ontological and epistemological circularity. In particular, once his interactionism, perspectivism, emergentism, and compatibilism are explicated, it is possible to see that Mead's "taking the perspective of the other" is not primarily a process of internalization that requires a preexisting "internalizer," but a process of participation with others within conventionalized sequences of interactivity. This participatory process enables the development of prereflective forms of perspective taking and self-other differentiation that serve as necessary conditions for the further emergence of more reflective forms of perspective taking, self-consciousness, and deliberative agency. Compatibilist interpretations of deliberative agency, thus understood, also are discussed. (shrink)

In their account of learning and behavior, the authors define an interactor as emitted behavior that operates on the environment, which excludes Pavlovian learning. A unified neural-network account of the operant-Pavlovian dichotomy favors interpreting neurons as interactors and synaptic efficacies as replicators. The latter interpretation implies that single-synapse change is inherently Lamarckian.

The proteasome family of proteases comprises oligomeric assemblies of very different symmetry. In different sizes, it features ring‐like oligomers with dihedral symmetry that allow the stacking of further rings of regulatory subunits as observed in the modular proteasome system, but also less symmetric helical assemblies. Comprehensive sequence and structural analyses of proteasome homologs reveal a parsimonious scenario of how symmetry may have emerged from a monomeric ancestral precursor and how it may have evolved throughout the proteasome family. The four characterized (...) representatives—ancestral β subunit (Anbu), HslV, betaproteobacterial proteasome homolog (BPH), and the 20S proteasome—are outlasting cornerstones in the family's evolutionary history, each marking a transition in symmetry. This article contextualizes the evolutionary and functional key aspects of these symmetry transitions, explaining how they facilitated the diversification and concurrent evolution of independent proteolytic systems side by side, each with its customized network of auxiliary interactors. -/- . (shrink)

Since most of the functions in cells are mediated by multimeric protein complexes, the determination of protein–protein interactions is an important step in the study of cellular mechanisms. Traditionally, after screening for possible target interactors by means of a yeast two‐hybrid screen, several methods are used to validate the initial result before carrying out functional experiments. Nowadays, non‐invasive fluorescence‐based methods like Bioluminescence Resonance Energy Transfer (BRET) and Fluorescence Resonance Energy Transfer (FRET) are widely used in the study of protein–protein (...) interactions in living cells. In the present review, we address the individual strengths and weaknesses of both RET approaches, providing information on their possible future use in the study of G protein‐coupled receptor oligomerization. BioEssays 30:82–89, 2008. © 2007 Wiley Periodicals, Inc. (shrink)

David Hull’s book (1988) provides an evolutionary account of the development of science which pays attention to both the social and conceptual aspects of that process. Unlike most philosophers who only invoke Darwinian metaphors in a casual way, Hull takes the analogy between the biological evolution of species and the growth of scientific knowledge quite seriously and by providing abstract definitions of terms such as replicator, interactor and lineage, he makes it possible for us to see clearly the structural similarities (...) between the two historical processes.Other symposiasts will comment on how tight that analogy really is. I must remark in passing that I have never understood the intense interest which evolutionary epistemologists take in this comparison. Surely our major job is to understand how science works, perhaps by using evolutionary theory as a fallible heuristic, but nothing seems to hinge on the extent of the formal analogy. (shrink)

In communication studies, in contrast to the approach of the information-transmission hypothesis, the dynamic systems theory tackles the problem of continous feedback between interactors. However, Shanker & King's (S&K's) account seems to lack methodological elaboration, for the reader is presented with anecdotes. Furthermore, in contrast to the authors' beliefs, chimpanzees (and humans) are not the only animals able to show coregulated communicative interactions, for similar phenomena can be found in other animals, as for example in dogs.

The units or levels of selection debate concerns the question of what kind of biological systems are stable enough that part of their evolution is a result of the process of natural selection acting at their level. Traditionally, the debate has concerned at least two different, though related, questions: the question of the level at which interaction with the environment occurs, and the question of the level at which reproduction occurs. In recent years, biologists and philosophers have discussed a new (...) aspect of this debate, namely the possibility that certain multi-species consortia formed by a host and its microbiome may act as a unit of selection. This thesis, however, has not been without criticism, as it is doubtful that such consortia could meet the conditions required to achieve the degree of stability that would allow them to experience natural selection. The purpose of this paper is to systematically examine such criticisms and to defend the thesis that the holobiont/hologenome can act as a genuine level of selection both in the form of an interactor and in the form of a reproducer. To do so, it will be argued that the microbiome should be characterized in functional rather than taxonomic terms. (shrink)

Chromatin‐bound proteins underlie several fundamental cellular functions, such as control of gene expression and the faithful transmission of genetic and epigenetic information. Components of the chromatin proteome (the “chromatome”) are essential in human life, and mutations in chromatin‐bound proteins are frequently drivers of human diseases, such as cancer. Proteomic characterization of chromatin and de novo identification of chromatin interactors could, thus, reveal important and perhaps unexpected players implicated in human physiology and disease. Recently, intensive research efforts have focused on (...) developing strategies to characterize the chromatome composition. In this review, we provide an overview of the dynamic composition of the chromatome, highlight the importance of its alterations as a driving force in human disease (and particularly in cancer), and discuss the different approaches to systematically characterize the chromatin‐bound proteome in a global manner. (shrink)

Many things evolve: species, languages, sports, tools, biological niches, and theories. But are these real instances of natural selection? Current assessments of the proper scope of Darwinian theory focus on the broad similarity of cultural or non-organic processes to familiar central instances of natural selection. That similarity is analysed in terms of abstract functional descriptions of evolving entities (e.g. replicators, interactors, developmental systems etc). These strategies have produced a proliferation of competing evolutionary analyses. I argue that such reasoning ought (...) not to be employed in arbitrating debates about whether particular phenomena count as instances of natural selection. My argument is based on hierarchical functional descriptions of natural selection. I suggest that natural selection ought not to be thought of as a single process but rather as a series of processes which can be analysed in terms of a hierarchy of functional descriptions (in much the same way as many people think of cognition). This, in turn, casts doubt on the idea that it is possible in principle to settle debates about whether particular phenomena count as instances of natural selection. (shrink)

Frente a una América Latina movilizada, conflictuada y atravesada por conatos de violencia interactoral, cívica-contestataria y política, y ante los abusos de gobiernos que resultan en reclamos y nuevas prácticas políticas de los sujetos sin derechos, se genera un escenario de riesgo para la endeble democracia. En virtud de esto el autor analiza la democracia no sólo en torno a los procesos y eventos electorales sino tambi{en abarcando otras aristas de este fenómeno, como la participación, las movilizaciones, los nuevos actores (...) y los comportamientos de las multitudes, buscando dar cuenta sobre los riesgos de la democracia. (shrink)

: This article describes a psychological test of Hull's (1988) theory of science as an evolutionary process by seeing if it can account for how scientists sometimes remember and cite the scientific literature. The conceptual adequacy of Hull's theory was evaluated by comparing it to Bartlett's (1932) seminal theory of human remembering. Bartlett found that remembering is an active, reconstructive process driven by a schema that biases recall in the direction of proto- typicality and personal involvement. This account supports Hull's (...) theory of science because it shows that the characteristics of reconstructive remembering are consistent with the generic properties of an evolutionary process. The empirical adequacy of Hull's theory was evaluated by comparing the predictions made from this evolutionary viewpoint against evidence from the history of science. Six cases studies of well-known psychological experiments that had been subject to repeated miscitation errors were collected and reviewed. All six case studies revealed a systematic pattern of distortions that is consistent with the schema-induced biases of reconstructive remembering. These findings support Hull's claim that science is an evolutionary process with scientists as interactors, scientific beliefs as replicators, and schemata as means for that replication. (shrink)

SummaryMis‐regulation (e.g. overproduction) of the human Ndc80/Hec1 outer kinetochore protein has been associated with aneuploidy and tumourigenesis, but the genetic basis and underlying mechanisms of this phenomenon remain poorly understood. Recent studies have identified the ubiquitous Ndc80 internal loop as a protein‐protein interaction platform. Binding partners include the Ska complex, the replication licensing factor Cdt1, the Dam1 complex, TACC‐TOG microtubule‐associated proteins (MAPs) and kinesin motors. We review the field and propose that the overproduction of Ndc80 may unfavourably absorb these (...) class='Hi'>interactors through the internal loop domain and lead to a change in the equilibrium of MAPs and motors in the cells. This sequestration will disrupt microtubule dynamics and the proper segregation of chromosomes in mitosis, leading to aneuploid formation. Further investigation of Ndc80 internal loop‐MAPs interactions will bring new insights into their roles in kinetochore‐microtubule attachment and tumourigenesis. (shrink)