Although sexual antagonism may have played a role in forming some sex chromosome systems, there appears to be little empirical or theoretical justification in assuming that it is the driving force in all cases of sex chromosome evolution. In many species, sex chromosomes have diverged in size and shape through the accumulation of mutations in regions of suppressed recombination. It is commonly assumed that recombination is suppressed in sex chromosomes due to selection to resolve sexually antagonistic pleiotropy. However, (...) the requirement for a sex chromosome‐specific mechanism for suppressing recombination is questionable, since more general models of recombination suppression on autosomes also appear to be applicable to sex chromosomes. Direct tests of the predictions of the sexual antagonism hypothesis offer only limited support in specific sex chromosome systems and circumstantial evidence remains open to interpretation. (shrink)

The creeping vole Microtus oregoni exhibits remarkably transformed sex chromosome biology, with complete chromosome drive/drag, X‐Y fusions, sex reversed X complements, biased X inactivation, and X chromosome degradation. Beginning with a selfish X chromosome, I propose a series of adaptations leading to this system, each compensating for deleterious consequences of the preceding adaptation: (1) YY embryonic inviability favored evolution of a selfish feminizing X chromosome; (2) the consequent Y chromosome transmission disadvantage favored X‐Y fusion (“XP”); (3) Xist‐based silencing of Y‐derived (...) XP genes favored a second X‐Y fusion (“XM”); (4) X chromosome dosage‐related costs in XPXM males favored the evolution of XM loss during spermatogenesis; (5) X chromosomal dosage‐related costs in XM0 females favored the evolution of XM drive during oogenesis; and (6) degradation of the non‐recombining XP favored the evolution of biased X chromosome inactivation. I discuss recurrent rodent sex chromosome transformation, and selfish genes as a constructive force in evolution. (shrink)

A great deal of progress has recently been made in characterizing the “mechanisms of aging.” A comparison with the mechanisms of development shows that the two sets of mechanisms are different; nevertheless, mechanisms of aging are conditioned by what happens during development. Aging and development also share some characteristics, such as a similar difficulty in attributing a precise temporal boundary to these processes. Other characteristics seem more specific to aging, such as the role of external (to the organism) and stochastic (...) events in its progression. In fact, both development and aging are historical processes with a mixture of stochastic events and deterministic processes, the ratio of the two being different in each process. Therefore, it is concluded that aging does not fit with a broad, lifelong conception of development. (shrink)

Given that natural selection is so powerful at optimizing complex adaptations, why does it seem unable to eliminate genes (susceptibility alleles) that predispose to common, harmful, heritable mental disorders, such as schizophrenia or bipolar disorder? We assess three leading explanations for this apparent paradox from evolutionary genetic theory: (1) ancestral neutrality (susceptibility alleles were not harmful among ancestors), (2) balancing selection (susceptibility alleles sometimes increased fitness), and (3) polygenic mutation-selection balance (mental disorders reflect the inevitable mutational load on the thousands (...) of genes underlying human behavior). The first two explanations are commonly assumed in psychiatric genetics and Darwinian psychiatry, while mutation-selection has often been discounted. All three models can explain persistent genetic variance in some traits under some conditions, but the first two have serious problems in explaining human mental disorders. Ancestral neutrality fails to explain low mental disorder frequencies and requires implausibly small selection coefficients against mental disorders given the data on the reproductive costs and impairment of mental disorders. Balancing selection (including spatio-temporal variation in selection, heterozygote advantage, antagonistic pleiotropy, and frequency-dependent selection) tends to favor environmentally contingent adaptations (which would show no heritability) or high-frequency alleles (which psychiatric genetics would have already found). Only polygenic mutation-selection balance seems consistent with the data on mental disorder prevalence rates, fitness costs, the likely rarity of susceptibility alleles, and the increased risks of mental disorders with brain trauma, inbreeding, and paternal age. This evolutionary genetic framework for mental disorders has wide-ranging implications for psychology, psychiatry, behavior genetics, molecular genetics, and evolutionary approaches to studying human behavior. (Published Online November 9 2006) Key Words: adaptation; behavior genetics; Darwinian psychiatry; evolution; evolutionary genetics; evolutionary psychology; mental disorders; mutation-selection balance; psychiatric genetics; quantitative trait loci (QTL). (shrink)

Ecological Immunology assumes that immunological defenses must be minimized in terms of cost (energy expenditure). To reach this goal, a complex and still largely unexplored strategy has evolved to assure survival. From invertebrates to vertebrates, an integrated immune–neuroendocrine response appears to be crucial for the hierarchical redistribution of resources within the body according to the specific ecological demands. Thus, on the basis of experimental data on the intimate relationship between stress and immune responses that has been maintained during evolution, we (...) argue that a broader perspective based on the integration of immune and neuroendocrine responses should be adopted to describe the comprehensive strategy that the body utilizes to adapt to dynamic environmental conditions. We discuss the hypothesis that a bow‐tie architecture might be suitable to describe the variety of immune–neuroendocrine inputs that continuously target cells and organs while, at the same time, fulfilling the basic requirement of minimizing the cost of immune–neuroendocrine responses. Bow‐tie architectures are able to convert a variety of stimuli (fan in) into a wide range of fine‐tuned responses (fan out) by passing through the integrating activity of a core (knot) constituted by a limited number of elements. Finally, we argue that the ecologically negotiated immune–neuroendocrine strategies may have deleterious effects in the post‐reproductive period of life when, at least in humans, chronic, low‐grade, systemic inflammation develops, in accordance with the antagonistic pleiotropy theory of aging. BioEssays 30:868–874, 2008. © 2008 Wiley Periodicals, Inc. (shrink)

Genomes are inherently unstable because of the need for DNA sequence variation as a substrate for evolution through natural selection. However, most multicellular organisms have postmitotic tissues, with limited opportunity for selective removal of cells harboring persistent damage and deleterious mutations, which can therefore contribute to functional decline, disease, and death. Key in this process is the role of genome maintenance, the network of protein products that repair DNA damage and signal DNA damage response pathways. Genome maintenance is beneficial early (...) in life by swiftly eliminating DNA damage or damaged cells, facilitating rapid cell proliferation. However, at later ages accumulation of unrepaired damage and mutations, as well as ongoing cell depletion, promotes cancer, atrophy, and other deleterious effects associated with aging. As such, genome maintenance and its phenotypic sequelae provide yet another example of antagonistic pleiotropy in aging and longevity. (shrink)

Genetic analysis of Drosophil has provided evidence in support of two proposed evolutionary genetic mechanisms of aging: mutation accumulation and antagonistic pleiotropy. Both mechanisms result from the lack of natural selection acting on old organisms. Analyses of large numbers of flies have revealed that mortality rates do not continue to rise with age as previously thought, but plateau at advanced ages. This phenomenon has implications both for models and for definitions of aging, and may be explained by the (...) evolutionary theories. The physiological processes and genes most relevant to aging are being identified using Drosophila lines selected in the laboratory for postponed senescence. Oxidative stress and insufficient metabolic reserves/capacity may be particularly important factors in limiting the fruitfly lifespan. Genes which exhibit aging‐related changes in expression are now being identified. Transgenic flies are being used to analyze the mechanisms of such aging‐related gene expression, and to test the effects of specific genes on aging and aging‐related deterioration. (shrink)

Understanding how traits are integrated at the organismal level remains a fundamental problem at the interface of developmental and evolutionary biology. Hormones, regulatory signaling molecules that coordinate multiple developmental and physiological processes, are major determinants underlying phenotypic integration. The probably best example for this is the lipid-like juvenile hormone (JH) in insects. Here we review the manifold effects of JH, the most versatile animal hormone, with an emphasis on the fruit fly Drosophila melanogaster, an organism amenable to both genetics and (...) endocrinology. JH affects a remarkable number of processes and traits in Drosophila development and life history, including metamorphosis, behavior, reproduction, diapause, stress resistance and aging. While many molecular details underlying JH signaling remain unknown, we argue that studying “hormonal pleiotropy” offers intriguing insights into phenotypic integration and the mechanisms underlying life history evolution. In particular, we illustrate the role of JH as a key mediator of life history trade-offs. BioEssays 27:999–1010, 2005. © 2005 Wiley Periodicals, Inc. (shrink)

Recent work on gene concepts has been influenced by recognition of the extent to which RNA transcripts from a given DNA sequence yield different products in different cellular environments. These transcripts are altered in many ways and yield many products based, somehow, on the sequence of nucleotides in the DNA. I focus on alternative splicing of RNA transcripts (which often yields distinct proteins from the same raw transcript) and on 'gene sharing', in which a single gene produces distinct proteins with (...) the exact same amino acid sequence. These are instances of molecular pleiotropy, in which distinct molecules are derived from a single putative gene. In such cases the cellular and external environments play major roles in determining which protein is produced. Where there is molecular pleiotropy, alternative gene concepts are naturally deployed; molecular epigenesis (revision of sequence-based information by altering molecular conformations or by action of non-informational molecules) plays a major role in orderly development. These results show that gene concepts in molecular biology do, and should, have both structural and functional components. They also show the need for a plurality of gene concepts and reveal fundamental difficulties in stabilizing gene concepts solely by reference to nucleotide sequence. (shrink)

We contend that social science variables are the product of multiple partly heritable traits. Genetic associations with socioeconomic status (SES) may differ across populations, but this is a consequence of the intermediary traits associated with SES differences also varying. Furthermore, genetic data allow social scientists to make causal statements regarding the aetiology and consequences of SES.

Living organisms are exposed to numerous influencing factors. This holds also true for their infrastructures that are processing and transducing information like endocrine networks or nerval channels. Therefore, the ability to compensate for noise is crucial for survival. An efficient mechanism to neutralise disturbances is instantiated in form of parallel complementary communication channels exerting antagonistic effects at their common receivers. Different signal processing types share the ability to suppress noise, to widen the system’s regulation capacity, and to provide for (...) variable gains while leaving the transferred signal to a large extent unchanged. (shrink)

In the context of the recent proliferation of nationalisms and enemy figures, this paper agrees with the desirability of retaining some of the explanatory and motivational potential of an agonistic account of politics, but gives reasons not to accept too much of Carl Schmitt's account of citizenship. The claim as to the necessarily antagonistic exclusion of concrete others can be supported neither on its own terms nor on Derridian grounds, as Chantal Mouffe, in particular, attempts to do. I then (...) indicate that différance may nonetheless account for strong (but not necessary) tendencies toward exclusion as well as for the intrinsic contradictions of liberal universalism. (shrink)

A systematic treatment of Hume's conception of imagination in all the main topics of his philosophy.

As an outspoken public intellectual Slavoj Žižek’s comments on today’s refugee crisis, particularly in relation to Syria, have been widely criticized. The following essay looks at the philosophy and politics of Žižek in relation to theorists such as Ranciere, Laclau and Mouffe in order to explore where Žižek’s dismissal of migrant struggle highlights the failure of his Lacan inspired Kantian transcendentalism and State based class politics to explore the political and subversive potentials of alternative sites of struggle. While Žižek’s exploration (...) of antagonism as a site of politics remains useful, his vision of State politics and class struggle as the bearers of anti- or alter-capitalist struggle, based on a Universalist politics and transcendental subject, fails to consider the multifarious political aspects of global mobility. (shrink)

This article focuses on three recent controversies in which Žižek has been embroiled and for which he has taken positions that rest on the notion of antagonism. His views on Eurocentrism, the European refugee crisis and trans politics have been the subject of notable disapproval, if not denunciation. Critics reproach him for being Eurocentric, racist and transphobic, charges which he has repeatedly countered. The article will examine the differing theoretical and political positions in these debates, underlining what Žižek’s critics miss (...) or misunderstand about his notion of antagonism. While I side firmly with Žižek on the substance of these issues, I nonetheless consider the extent to which at least part of the disagreement here centres on the performative rather than the strictly “theoretical”: Might his critics be reacting to his overexposure? Could such overexposure be interpreted as an attempt at having the last word? And to what extent does the antagonistic form of Žižek’s interventions militate against their theoretical content? (shrink)

In discussing the relationship between genetically influenced differences and educational attainment (EA), Burt employs the concept of downward causation. I note the similarities between Burt's concept of downward causation and the sociogenomics concept of vertical pleiotropy and argue that her discussion of downward causation introduces an unnecessary normative component. The core problem concerns not the appropriateness of phenotypes that influence EA but mistaken assumptions about which phenotypes are being predicted.

Pleiotropy, in which one mutation causes multiple phenotypes, has traditionally been seen as a deviation from the conventional observation in which one gene affects one phenotype. Epistasis, or gene–gene interaction, has also been treated as an exception to the Mendelian one gene–one phenotype paradigm. This simplified perspective belies the pervasive complexity of biology and hinders progress toward a deeper understanding of biological systems. We assert that epistasis and pleiotropy are not isolated occurrences, but ubiquitous and inherent properties of (...) biomolecular networks. These phenomena should not be treated as exceptions, but rather as fundamental components of genetic analyses. A systems level understanding of epistasis and pleiotropy is, therefore, critical to furthering our understanding of human genetics and its contribution to common human disease. Finally, graph theory offers an intuitive and powerful set of tools with which to study the network bases of these important genetic phenomena. (shrink)

This article offers a pragmatic and relational analysis of the controversial heuristic of cultural resistance and presents some of the problems that affect the production and distribution of the poetic discourses of resistance and emancipation. To that end, it focuses on the incorporation of the historicity and the historic contingency of conflict as key elements of the subjectification constituted by the poem of resistance as “poem for the political”. It also explores the applicability of certain notions common to the contemporary (...) critical tradition, as developed by scholars such as Badiou, Mouffe, Rancière, Bal and Žižek. (shrink)

ABSTRACTThis research examines how fake identities on social media create and sustain antagonistic and racist discourses. It does so by analysing 11 Danish Facebook pages, disguised as Muslim extremists living in Denmark, conspiring to kill and rape Danish citizens. It explores how anonymous content producers utilise Facebook’s socio-technical characteristics to construct, what we propose to term as, platformed antagonism. This term refers to socio-technical and discursive practices that produce new modes of antagonistic relations on social media platforms. Through (...) a discourse-theoretical analysis of posts, images, ‘about’ sections and user comments on the studied Facebook pages, the article highlights how antagonism between ethno-cultural identities is produced on social media through fictitious social media accounts, prompting thousands of user reactions. These findings enhance our current understanding of how antagonism and racism are constructed and amplified within social media environments. (shrink)

We explore the legalization of the cannabis industry in the US, and point at the conflicted path through which this emerging industry has traversed. In particular, we highlight how this industry has navigated controversy to become one of the fastest growing industries in the world. The paper also offers a theoretical model that explains the role played by social movements to propel and shape early antagonism towards increasing protagonism. Evidence of the latter is seen in the form of cannabis laws (...) passing at the state level in the US. We posit that resource mobilization and shaping effects were instrumental in laying the grounds for legalization. A detailed timeline of the legalization for over one and a half centuries is also provided. Our synergistic approach integrates a historical perspective with social movement theory to address a relatively new and under examined phenomenon in the emerging US legal cannabis industry and ensuing ethical implications. (shrink)

To disentangle liberal democratic theory from its rationalism and orientation towards consensus, Chantal Mouffe recommends reviving Machiavelli’s argument about the institutionalization of conflict. Democracy, she argues, needs to establish a vibrant public sphere in which collective identities can openly contend with each other in an adversarial left/right format. Such an institutionalization of conflict is easily imaginable in the form of, and well known from, parliamentary party politics. But is it extendable to those extra-parliamentary forms of politics that increasingly appear to (...) supplement democratic parliamentarism? Does the ‘becoming-other of politics’ suit or defy the institutionalization of conflict? (shrink)

Numerous mediators are involved in both the control and the transmission of nociceptive messages, and several lines of research have been developed in the management of pain. Complete enkephalin- degrading enzyme inhibitors, which produce naloxone-reversible analgesia in all tests where morphine has been found to be active, remains the most promising way. CCK compounds, especially the CCKB antagonists also may be interesting drugs. Indeed, they are able to strongly potentiate the antinociceptive effects of the opioids. [dickenson, wiesenfeld-hallin et al.].

The vast majority (> 95%) of single-gene mutations in yeast affect not only the expression of the mutant gene, but also the expression of many other genes. These data suggest the presence of a previously uncharacterized ‘gene expression network’—a set of interactions between genes which dictate gene expression in the native cell environment. Here, we quantitatively analyze the gene expression network revealed by microarray expression data from 273 different yeast gene deletion mutants.(1) We find that gene expression interactions form a (...) robust, error-tolerant ‘scale-free’ network, similar to metabolic pathways(2) and artificial networks such as power grids and the internet.(3-5) Because the connectivity between genes in the gene expression network is unevenly distributed, a scale-free organization helps make organisms resistant to the deleterious effects of mutation, and is thus highly adaptive. The existence of a gene expression network poses practical considerations for the study of gene function, since most mutant phenotypes are the result of changes in the expression of many genes. Using principles of scale-free network topology, we propose that fragmenting the gene expression network via ‘genome-engineering’ may be a viable and practical approach to isolating gene function. BioEssays 24:267–274, 2002. © 2002 Wiley Periodicals, Inc.; DOI 10.1002/bies.10054. (shrink)

Two classic theories maintain that aging evolves either because of alleles whose deleterious effects are confined to late life or because of alleles with broad pleiotropic effects that increase early‐life fitness at the expense of late‐life fitness. However, empirical studies often reveal positive pleiotropy for fitness across age classes, and recent evidence suggests that selection on early‐life fitness can decelerate aging and increase lifespan, thereby casting doubt on the current consensus. Here, we briefly review these data and promote the (...) simple argument that aging can evolve under positive pleiotropy between early‐ and late‐life fitness when the deleterious effect of mutations increases with age. We argue that this hypothesis makes testable predictions and is supported by existing evidence. (shrink)

There is currently great controversy over the contribution antimicrobial use in animal agriculture has made to antimicrobial resistance in pathogenic bacteria with negative consequences for human health. In light of this, the approval process for antimicrobials used in US animal agriculture, known as New Animal Drug Application or NADA, is currently being revised by the federal government. We explore the public deliberations over the development of these new policies focusing our attention on the interaction between pharmaceutical companies and the U.S. (...) Food and Drug Administration. What appears to be an antagonistic public discourse is examined in terms of its ability to simultaneously legitimate the roles of the Food and Drug Administration as the official arbiter of policy on antimicrobial use in animal agriculture and as a protector of the public welfare, as well as the role of pharmaceutical companies as the producers of safe and effective products necessary for the protection of public well-being. (shrink)

This book combines performance analysis with contemporary political philosophy to advance new ways of understanding both political performance and the performativity of the politics of the street. Our times are pre-eminently political times and have drawn radical responses from many theatre and performance practitioners. However, a decade of conflict in the Middle East and Afghanistan, the eruption of new social movements around the world, the growth of anti-capitalist and anti-globalisation struggles, the upsurge of protests against the blockades of neoliberalism, and (...) the rising tide of dissent and anger against corporate power, with its exorbitant social costs, have left theatre and performance scholarship confronting something of a dilemma: how to theorize the political antagonisms of our day? Drawing on the resources of ‘post-Marxist’ political thinkers such as Chantal Mouffe and Jacques Rancière, the book explores how new theoretical horizons have been made available for performance analysis. (shrink)