Epigenetics, Responsiveness and Embodiment

This short paper comments on the connections between epigenetics, responsiveness and embodiment. Epigenetics has solidified a new conception of DNA as “responsive,” and rightfully so. Yet, the discussion too easily falls back to metaphors of agency and can show a tendency to see responsiveness and embodiment as based on epigenetics, which is shown to be wrong

Introduction: sketches of a conceptual history of epigenesis

This is an introduction to a collection of articles on the conceptual history of epigenesis, from Aristotle to Harvey, Cavendish, Kant and Erasmus Darwin, moving into nineteenth-century biology with Wolff, Blumenbach and His, and onto the twentieth century and current issues, with Waddington and epigenetics. The purpose of the topical collection is to emphasize how epigenesis marks the point of intersection of a theory of biological development and a (philosophical) theory of active matter. We also wish to show that the concept of epigenesis existed prior to biological theorization and that it continues to permeate thinking about development in recent biological debates

Conceptual Histories in Psychiatry: Perspectives Across Time, Language and Culture in the Work of German Berrios

Psychiatry is inherently complex and vast amounts of material have been written on the topic. One of the largest collections of the extant material is archived in German Berrios’ personal library. The synthesis of this material has come to life through his rare powers of intellect, eidetic memory, and decades of early morning reading in a variety of languages. Its expression has taken many forms, including a series of conceptual histories on psychiatric topics. Conceptual history teases out the historical semantics of a concept, what it meant to people using the term in different ages, in different languages, against what contextual background. Accompanying German Berrios on these journeys has for many clinicians, academics, and others been a stimulating, thought-provoking, and mind-opening experience. An early adopter of and advocate for information technology in publishing both old and new, Berrios continues to influence the way we think, and his legacy will shape the minds of many people addressing the mysteries in the mind and brain sciences in years to come. This paper attempts to bring together some of the extraordinary characteristics of German the person and his remarkable contributions to scholarship

Histone Methylome of the Human Parasite Schistosoma Mansoni

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Phenotypic plasticity: From microevolution to macroevolution

International audienceThis chapter starts with a short history of the concept of phenotypic plasticity (from the seventeenth century to present) in order to distinguish two distinct conceptions of plasticity: one more dynamic (or Aristotelian) according to which the notion has been described as a property inherent to life whose very organization depends upon it, and an other conception, more passive, according to which " plasticity " means the capacity to express different phenotypes for a single genotype depending on environmental conditions. The chapter shows then how Darwinian theories have first favored the second conception, before the emergence of a renewed interest for the first one, which plays the role of an explanans, while the second conception would rather be an explanandum. In so doing, the chapter describes in depth the role of the concept in micro-and macroevolution study. The concept of plasticity is everywhere in the life sciences. As in philosophy, 1 the term can have two meanings: in the active sense, the concept of plasticity is synonymous with " that which has the power to shape or form " with the example in biology being the egg cell development, which has the plastic capacity to generate a mul-ti-celled organism; in the passive sense, the concept expresses a " susceptibility to take on an indefinite number of forms " , with the example in evolutionary biology being " phenotypic plasticity " , which we will define here as an organisms' capacity to express different phenotypes of a single genotype as a function of environmental conditions. The concept of plasticity is then, in its passive sense, linked to evolu-1 Godin (2004), Dictionnaire de philosophie, Fayard/éditions du Temps

Between explanans and explanandum: biodiversity and the unity of theoretical ecology

International audienceBiodiversity is arguably a major concept in ecology. Some of the key questions of the discipline are: why are species distributed the way they are, in a given area, or across areas? Or: why are there so many animals (as Hutchinson asked in a famous paper)? It appears as what is supposed to be explained, namely an explanandum of ecology. Various families of theories have been proposed, which are nowadays mostly distinguished according to the role they confer to competition and the competitive exclusion principle. Niche theories, where the difference between "fundamental" and "realised" niches (Hutchinson 1959) through competitive exclusion explains species distributions, contrast with neutral theories, where an assumption of fitness equivalence, species abundance distributions are explained by stochastic models, inspired by Hubbell (2001). Yet, while an important part of community ecology and biogeography understands biodiversity as an explanan-dum, in other areas of ecology the concept of biodiversity rather plays the role of the explanans. This is manifest in the long lasting stability-diversity debate, where the key question has been: how does diversity beget stability? Thus explanatory reversibility of the biodiversity concept in ecology may prevent biodiversity from being a unifying object for ecology. In this chapter, I will describe such reversible explanatory status of biodiversity in various ecological fields (biogeography, functional ecology, community ecology). After having considered diversity as an explanandum, and then as an explanans, I will show that the concepts of biodiversity that are used in each of these symmetrical explanatory projects are not identical nor even equivalent. Using an approach to the concept of biodiversity in terms of "conceptual space", I will finally argue that the lack of unity of a biodiversity concept able to function identically as explanans and explanandum underlies the structural disunity of ecology that has been pointed out by some historians and philosophers

Phenotypic plasticity and modularity allow for the production of novel mosaic phenotypes in ants

International audienceBackground: The origin of discrete novelties remains unclear. Some authors suggest that qualitative phenotypic changes may result from the reorganization of preexisting phenotypic traits during development (i.e., developmental recombination) following genetic or environmental changes. Because ants combine high modularity with extreme phenotypic plasticity (queen and worker castes), their diversified castes could have evolved by developmental recombination. We performed a quantitative morphometric study to investigate the developmental origins of novel phenotypes in the ant Mystrium rogeri, which occasionally produces anomalous 'intercastes. ' Our analysis compared the variation of six morphological modules with body size using a large sample of intercastes. Results: We confirmed that intercastes are conspicuous mosaics that recombine queen and worker modules. In addition, we found that many other individuals traditionally classified as workers or queens also exhibit some level of mosaicism. The six modules had distinct profiles of variation suggesting that each module responds differentially to factors that control body size and polyphenism. Mosaicism appears to result from each module responding differently yet in an ordered and predictable manner to intermediate levels of inducing factors that control polyphenism. The order of module response determines which mosaic combinations are produced. Conclusions: Because the frequency of mosaics and their canalization around a particular phenotype may evolve by selection on standing genetic variation that affects the plastic response (i.e., genetic accommodation), developmental recombination is likely to play an important role in the evolution of novel castes in ants. Indeed, we found that most mosaics have queen-like head and gaster but a worker-like thorax congruent with the morphology of ergatoid queens and soldiers, respectively. Ergatoid queens of M. oberthueri, a sister species of M. rogeri, could have evolved from intercastes produced ancestrally through such a process