The Epic of Evolution is a course taught at Northern Arizona University. It engages the task of formulating a new epic myth that is based on the physical, natural, social, and cultural sciences. It aims to serve the need of providing meaning for human living in the vast and complex universe that the sciences now depict for us. It is an interdisciplinary effort in an academic setting that is often divided by specializations; it focuses on values in a climate of (...) relativism; and it concentrates on an enterprise for which there are few textbooks at hand. The course is presented in three segments: the cosmos before humans appeared, the human phenomenon, and scenarios for the future of evolution. (shrink)

The concept of homology arose from classical studies of comprative morphology, and took on a new signficance with the advent of evolutionary theory. It is currentlyl undergoing antoher metamorphosis: many developmental geneticists now dfine homology as shared patterns of gene expression. However, this ne usage conflaes difinition with criteri, and fails to recognize the meaninful asignments of homology must speify a biologcal level. We argue the although developmental genetic data can help identify homologus structures. they are niether necessary (...) nor sufficient, and do not in any case jutify a new definition of homology. (shrink)

Although features of the dentition figure prominently in discussions of early hominid phylogeny, remarkably little is known of the developmental basis of the variations in occlusal morphology and dental proportions that are observed among taxa. Recent experiments on tooth development in mice have identified some of the genes involved in dental patterning and the control of tooth specification. These findings provide valuable new insight into dental evolution and underscore the strong developmental links that exist among the teeth and (...) the jaws and cranium. The latter has important implications for cladistic studies that traditionally consider features of the skull independently from the dentition. BioEssays 23:481–493, 2001. © 2001 John Wiley & Sons, Inc. (shrink)

The discovery, more than 60 years ago, of a mutant mouse with a short tail led to the birth of the new field of developmental genetics. Over the years since, numerous investigators have probed the biology of the original short‐tail mutation at the T locus, as well the naturally‐occurring t haplotypes that were uncovered as a result of their interaction with this mutation. Although the T locus ranks among the best characterized developmental loci in the mouse, it (...) was not among the first to be cloned. This situation has now been rectified with two recent reports from Herrmann, Lehrach and their colleagues. While the T locus is expressed uniquely in the embryonic tissues predicted from the mutant phenotype, the gene itself, as well as the predicted amino acid sequence of the T product, show no strong homology to any known sequence. For the moment, at least, the mystery behind the function of the T locus still awaits definitive resolution. (shrink)

The mechanisms responsible for the fine tuning of development, where the wildtype phenotype is reproduced with high fidelity, are not well understood. The difficulty in approaching this problem is the identification of mutant phenotypes indicative of a defect in these fine‐tuning control mechanisms. Evolutionary biologists have used asymmetry as a measure of developmental homeostasis. The rationale for this was that, since the same genome controls the development of the left and right sides of a bilaterally symmetrical organism, departures from (...) symmetry can be used to measure genetic or environmental perturbations. This paper examines the relationship between asymmtry and resistance to organophosphorous insecticides in the Australian sheep blowfly, Lucilia cuprina. A resistance gene, Rop‐1, which encodes a carboxylesterase enzyme, also confers a significant increase in asymmetry. Continued exposure of resistant populations to insecticide has selected a dominant suppressor of the asymmetry phenotype. Genetic evidence indicates that the modifier is the L. cuprina Notch homologue. (shrink)

The last decade has seen a dramatic increase in interest in the extent to which morphological evolution depends on changes in regulatory pathways. Insects provide a fertile ground for study because of their diversity and our high level of understanding of the genetic regulation of development in Drosophila melanogaster. However, comparable genetic approaches are presently possible in only a small number of non‐Drosophilid insects. In a recent paper, Hughes and Kaufman(1) have used a new methodology, RNA interference, in the milkweed (...) bug, Oncopeltus fasciatus, to phenocopy the effects of mutations in Hox genes. RNA interference involves the injection of double‐stranded RNA of the same sequence as the relevant mRNA resulting in a depletion of that transcript.(2) Hughes and Kaufman focused on the gnathal segments, which elaborate specialized appendages important to feeding. Their results indicate that gnathal adaptations in this bug are correlated with changes in Hox gene functions and interactions. BioEssays 23:379–382, 2001. © 2001 John Wiley & Sons, Inc. (shrink)

We may now ask the question: In what historical perspective should we place the work of Richard Goldschmidt? There is no doubt that in the period 1910–1950 Goldschmidt was an important and prolific figure in the history of biology in general, and of genetics in particular. His textbook on physiological genetics, published in 1938, was an amazing compendium of ideas put forward in the previous half-century about how genes influence physiology and development. His earlier studies on the genetic (...) and geographic distribution of the various species and races of Lymantria contributed soundly to an understanding of the inheritance and development of sex, as well as the genetics of speciation. He was a curious mixture of the experimentalist, empiricist, and theorizer, who could grasp both the large and the small at once and wrap them into the same integrated and coherent package.In insisting on trying to relate genetics to development, Goldschmidt was continually forced to speculate and to forsake experimental fact for generalized theory. In refusing to reconcile a physiological and developmental conception with a corpuscular theory of the gene, he forced himself to substitute for a large body of experimentally verified evidence, vague and general speculations which did not lead in any precise direction. L. C. Dunn summarizes succinctly the effect of Goldschmidt's thinking on the development of genetic theory: Although Goldschmidt's ideas had a considerable influence in directing attention to the developmental processes intervening between genes and characters, they did not lead to the establishment of a general theory of development in genetical terms. In fact, at the end of the period, as signalized by Goldschmidt's book of 1938 [Physiological Gentics] doubt remained whether there was a field with a defined problem which could be identified as developmental genetics.Yet the frequency with which Goldschmidt is cited by later writers suggests that there is a more positive side to his contribution than this. The early Mendelians had recognized the genic constitution of organisms and the Drosophila workers had uncovered in detail the chromosomal mechanism of heredity. These great discoveries were of classical character, solidly based on a multitude of well established facts. By themselves, however, they would not have been sufficient to place genetics in the central position within biology which it was to assume. Beyond the “static” analysis of gene transmission an insight was needed into the dynamic role of genes in cellular physiology, biochemistry, and development. Goldschmidt recognized this aspect and outlined in brilliant generalizations a physiological theory of genetics. Necessarily the prophetic nature of this achievement — romantic in the sense of Ostwald's classification of great scientists and their discoveries — transcended its factual basis. It was the audacity of the theoretician unimpeded by the still scanty data which gave a new focus to biological thought.Some have called Goldschmidt an “obstructionist” in the history of genetics—one whose efforts were largely directed toward useless and continual criticism — challenge for the sake of challenge. As this line of argument goes, time wasted answering Goldschmidt's poorly conceived criticisms could have been better used to pursue new lines of thought within the classical gene theory. Sometimes historians are upbraided for studying the work of such “obstructionists,” or even the work of those whose ideas have later proved to be inadequate. This argument misses the point of history and the lessons which it can teach. Perhaps Goldschmidt did take the time of a number of the classical geneticists who tried to answer his objections to the gene theory; and perhaps many of his own ideas about genes were, by today's view, “wrong.” These are always easier judgments to make by hindsight than at the moment. But that is not the point. Goldschmidt had a considerable influence on his contemporaries, and to dismiss him as an obstructionist because his opponents later proved to be more nearly right, distorts history and obscures significant questions which we might well be asking. It might be valuable to know why Goldschmidt felt compelled to be an iconoclast —and how that impulse, psychological in orgin, led him to overlook critical items of evidence which his opponents considered more carefully. It might also be valuable to try and understand how a contemporary of Goldschmidt or. Morgan really viewed the gene theory — what were its strong and weak point? Such questions are not readily answered by studying the work of only those men who were correct by later standards.Answers to some of the above questions can be gleaned from this study of Goldschmidt — though the first, and most psychologically oriented, question is largely untouched here.On the one hand, Goldschmidt forced classical geneticists to reexamine the foundation of their ideas about the nature, inviolability, and even physical dimensions of genes. He also kept alive the very real problems of gene physiology and its relations to development — a relationship that was given less attention by the Drosophila school in their pursuit of the transmission process. On a broader level he emphasized to the biological community a principle that was in danger of being lost in the enthusiasm surrounding the expansion of the Mendelian-chromosome theory. The point was that all theories in science are transient, logical constructs which should not be held as sacred. Time and again, as the history of science has shown, theories become rigid structures which retard new modes of thought. From Goldschmidt's perspective, the gene theory was in danger of performing just that function, for it was preventing workers from viewing the gene in a functional as well as a structural light.On the other hand, examining the work of critics (or even of outright “obstructionists”) gives the historian an opportunity to observe how the more established community of scholars at some point in time reacts to challenges of its cherished ideas. The fact that many workers in his own day (such as Beadle, Luria, Delbruck, Sturtevant, Bridges, and others), as well as most geneticists today, saw Goldschmidt as having been largely “obstructionist” is useful historical (and/or sociological) data. Clearly, as this paper has tried to show, Goldschmidt's ideas were not all obstructionist, and his viewpoint that genes must be considered functionally was one which was clearly valid, premature as it may have been from an experimental and technique point of view. Perhaps Goldschmidt's major fault was that he developed alternative theories which were not easily testable. Nonetheless, his challenge to a fundamental and established idea brought forth a reaction from many members of the genetic community which indicates how unwilling they were to reconsider the formalized theory on which their work was based. While many of Goldschmidt's criticisms — and particularly his way of making them — arose out of his own idiosyncrasies, they were also a product of his times. His view of the nature of theory-construction, and his rejection of old-style reductionism and mechanism, were part of a growing awareness within the world scientific community that explanations based on reducing complex phenomena to ultimate particles or units were clearly inadequate. The success of the Mendelian-chromosome theory had obscured that fact for many geneticists, but to Goldschmidt it was a point that could not be allowed to pass unnoticed. (shrink)

One of the bases of developmental genetics resides in the alliance of clonal analysis and genetic analysis. But the study of cell lineage — cells which have their genealogical relationship — and the study of the cellular labelled progeny, have their own history. We have tried to follow it since its foundation with C.O. Whitman (1878) and E.B. Wilson (1892). A.H. Sturtevant (1929) and C. Stern (1936) the first tools to study the 'cell lineage' in Drosophila. We stress (...) the contribution of the pioneer work realised around 1940. In the following period we witness the emergence of developmental genetics in Drosophila mainly with E. Hadorn (1949-1966), C. Stern (1954-1968) and E.B. Lewis (1963-1964). We conclude with A. Garcia-Bellido's view of compartments: supra-cellular units of development (1973). A postcript presents the most recent publications and some critical focuses. (shrink)

Much of the early history of developmental and physiological genetics in Germany remains to be written. Together with Carl Correns and Richard Goldschmidt, Alfred Kühn occupies a special place in this history. Trained as a zoologist in Freiburg im Breisgau, he set out to integrate physiology, development and genetics in a particular experimental system based on the flour moth Ephestia kühniella Zeller. This paper is meant to reconstruct the crucial steps in the experimental pathway that led Kühn (...) and his collaborators at the University of Göttingen, and later at the Kaiser Wilhelm Institutes of Biology and Biochemistry in Berlin, to formulate, in their specific way, what later became known as the "one gene-one enzyme hypothesis." Special attention will be given to the interaction of the different parts of Kühn's Ephestia-based project, which were rooted in different research traditions. The paper retraces how, roughly between 1925 and 1945, these elements came to form a mixed experimental setup composed of genetic, embryological, physiological and, finally, biochemical constituents. Accordingly, emphasis is laid on the development of the terminology in which the results were cast, and how it reflected the hybrid state of an experimental system successively acquiring new epistemic layers. (shrink)

In one of the first genetic screens aimed at identifying induced developmental mutants, Nadine Dobrovolskaïa-Zavadskaïa, working at the Pasteur Laboratory in the 1920s, isolated and characterized a mutation affecting Brachyury, a gene that regulates tail and axial development in the mouse. Dobrovolskaïa-Zavadskaïa's analysis of Brachyury and other mutations affecting tail development were among the earliest attempts to link gene action with a tissue-specific developmental process in a vertebrate. Her analyses of genes that interacted with Brachyury led to the (...) discovery of the t-haplotype chromosome of mouse. After 70 years, Brachyury and the multiple genes with which it interacts continue to occupy a prominent focus in developmental biology research. A goal of this review is to identify the contributions that Dobrovolskaïa-Zavadskaïa made to our current thinking about Brachyury and how she helped to shape the dawn of the field of developmental genetics. BioEssays 23:365–371, 2001. © 2001 John Wiley & Sons, Inc. (shrink)

The existence of a genetic program of development was proposed by molecular biologists in the nineteen-sixties. Historians and philosophers of science have since thoroughly criticized this notion. To fully appreciate its significance, it is interesting to consider the research which was pursued during this period by molecular biologists who proposed this notion. This study focuses on François Jacob's work and on the model of development supported by his lab in the early seventies, the T-complex model. This episode of Jacob's scientific (...) activity has since been forgotten. Characterization of this model shows that the notion of program was used in a metaphoric way and that it did not put any constraint on the work pursued in the lab at that time. Some attention is devoted to the origin of this metaphor in the context of the nineteen-seventies. (shrink)

The C. elegans male tail is being studied as a model to understand how genes specify the form of multicellular animals. Morphogenesis of the specialized male copulatory organ takes place in the last larval stages during male development. Genetic analysis is facilitated because the structure is not necessary for male viability or for strain propagation. Analysis of developmental mutants, isolated in several functional and morphological screens, has begun to reveal how fates of cells are determined in the cell lineages, (...) and how the specification of cell fates affects the morphology of the structure. Cytological studies in wild type and in mutants have been used to study the mechanism of pattern formation in the tail peripheral nervous system. The ultimate goal is to define the entire pathway leading to the male copulatory organ. (shrink)

The study of genetic developmental disorders originally seemed to hold the promise for those of a nativist persuasion of demonstrating pure dissociations between different cognitive functions, as well as the existence of innately specified modules in the brain and the direct mapping of mutated genes to specific cognitive-level outcomes. However, more recent research within a neuroconstructivist perspective has challenged this promise, arguing that earlier researchers lost sight of one fundamental explanatory factor in both the typical and atypical case: the (...) actual process of ontogenetic development. The paper is divided into three parts on evolution, genetics, and ontogeny. Each section starts by examining nativist claims about innateness and modularity of function, and subsequently evaluates them within a neuroconstructivist approach to human development. (shrink)

We examined the association of parents’ genetic causal beliefs and parenting behaviors, hypothesizing a positive association between parents’ genetic causal beliefs and their use of psychological control. Study 1 (N = 394) was a cross-sectional survey and revealed that parents’ genetic essentialism beliefs were positively associated with their self-reported use of harsh psychological control, but only for parents who reported relatively high levels of problem behaviors in their children. Study 2 (N = 293) employed a 4-day longitudinal design and revealed (...) that parents’ genetic causal beliefs positively predicted the use of psychological control, especially on days when they perceived relatively high problem behaviors in children. Overall, the studies demonstrated that parents’ genetic causal beliefs about character positively predicted psychologically controlling and harsh responses to child problem behaviors, which may ultimately be detrimental to child development. (shrink)

Charney's target article convincingly demonstrates the need for the discipline of quantitative human behavior genetics to discard its false assumptions and to employ the techniques, assumptions, and research program characteristic of modern developmental psychobiology.

Adaptive phenotypic plasticity allows organisms to cope with environmental variability, and yet, despite its adaptive significance, phenotypic plasticity is neither ubiquitous nor infinite. In this review, we merge developmental and population genetic perspectives to explore costs and limits on the evolution of plasticity. Specifically, we focus on the role of modularity in developmental genetic networks as a mechanism underlying phenotypic plasticity, and apply to it lessons learned from population genetic theory on the interplay between relaxed selection and mutation (...) accumulation. We argue that the environmental specificity of gene expression and the associated reduction in pleiotropic constraints drive a fundamental tradeoff between the range of plasticity that can be accommodated and mutation accumulation in alternative developmental networks. This tradeoff has broad implications for understanding the origin and maintenance of plasticity and may contribute to a better understanding of the role of plasticity in the origin, diversification, and loss of phenotypic diversity. (shrink)

Maynard Smith notes that he provides a natural history and not a philosophical analysis of the use of concepts of information in contemporary biology. Just a natural history, however rich, would do little to resolve the ongoing controversy about the role of these concepts in biology. None of the disputants deny that the biological use of these concepts is pervasive. The dispute is about whether these concepts—and the framework in which they are embedded—continue to be of explanatory value in contemporary (...) biology. Fortunately, Maynard Smith does much more than provide a natural history: his contribution is also a sustained attempt to justify many of the uses of information in biology. (shrink)

FOREWORD. Gilbert Gottlieb and the Developmental Point of View. I. INTRODUCTION. 1. Developmental Systems, Nature-Nurture, and the Role of Genes in Behavior and Development: On the Legacy of Gilbert Gottlieb. 2. Normally Occurring Environmental and Behavioral Influences on Gene Activity: From Central Dogma to Probabilistic Epigenesis. II. THEORETICAL FOUNDATIONS FOR THE DEVELOPMENTAL STUDY OF BEHAVIOR AND GENETICS. 3. Historical and Philosophical Perspectives on Behavioral Genetics and Developmental Science. 4. Development and Evolution Revisited. 5. Probabilistic (...) Epigenesis and Modern Behavioral and Neural Genetics. 6. The Roles of Environment, Experience, and Learning in Behavioral Development. 7. Contemporary Ideas in Physics and Biology in Gottlieb’s Psychology. III. EMPIRICAL STUDIES OF BEHAVIORAL DEVELOPMENT AND GENETICS. 8. Behavioral Development during the Mother-Young Interaction in Placental Mammals: The Development of Behavior in the Relationship with the Mother. 9. Amniotic Fluid as an Extended Milieu Interieur. 10. Developmental Effects of Selective Breeding for an Infant Trait. 11. Emergence and Constraint in Novel Behavioral Adaptations. 12. Nonhuman Primate Research Contributions to Understanding Genetic and Environmental Influences on Phenotypic Outcomes across Development. 13. Interactive Contributions of Genes and Early Experience to Behavioural Development: Sensitive Periods and Lateralized Brain and Behaviour. 14. Trans-Generational Epigenetic Inheritance. 15. The Significance of Non-Replication of Gene-Phenotype Associations. 16. Canalization and Malleability Reconsidered: The Developmental Basis of Phenotypic Stability and Variability. IV. APPLICATIONS TO DEVELOPMENT. 17. Gene-Parenting Interplay in the Development of Infant Emotionality. 18. Genetic Research in Psychiatry and Psychology: A Critical Overview. 19. On the Limits of Standard Quantitative Genetic Modeling of Inter-Individual Variation: Extensions, Ergodic Conditions and a New Genetic Factor Model of Intra-Individual Variation. 20. Songs My Mother Taught Me: Gene-Environment Interactions, Brain Development and the Auditory System: Thoughts on Non-Kin Rejection, Part II. 21. Applications of Developmental Systems Theory to Benefit Human Development: On the Contributions of Gilbert Gottlieb to Individuals, Families, and Communities. (shrink)

Using samples from three diverse populations, we test evolutionary hypotheses regarding how people reason about the inheritance of various traits. First, we provide a framework for differentiat-ing the outputs of mechanisms that evolved for reasoning about variation within and between biological taxa and culturally evolved ethnic categories from a broader set of beliefs and categories that are the outputs of structured learning mechanisms. Second, we describe the results of a modified “switched-at-birth” vignette study that we administered among children and adults (...) in Puno, Yasawa, and adults in the United States. This protocol permits us to study perceptions of prenatal and social transmission pathways for various traits and to differentiate the latter into vertical versus horizontal cultural influence. These lines of evidence suggest that people use all three mechanisms to reason about the distribution of traits in the population. Participants at all three sites develop expectations that morphological traits are under prenatal influence, and that belief traits are more culturally influenced. On the other hand, each population holds culturally specific beliefs about the degree of social influence on non-morphological traits and about the degree of vertical transmission—with only participants in the United States expecting parents to have much social influence over their children. We reinterpret people's differentiation of trait transmission pathways in light of humans' evolutionary history as a cultural species. (shrink)

More than 40 years ago, Gilbert Gottlieb and like-minded scholars argued for the philosophical necessity of approaching genetic contributions to development through a multilevel, bidirectional systems perspective. Charney's target article builds on this heritage in significant ways, offering more recent examples of the interactions of biology and context, as well as the diversity of developmental mechanisms, and reaffirming a way forward for genetic research.

This chapter contains sections titled: Introduction The Evolving Evolutionary Synthesis Population Genetics vs. Developmental Genetics Evo‐Devo's Central Target: The Study of Evolvability Origins? Conclusion Postscript: Counterpoint Acknowledgments References.

ZusammenfassungDer Artikel führt den Begriff der epistemischen Konkurrenz ein. Im Gegensatz zu „wissenschaftliche Kontroverse“ beschreibt er eine Situation, in der sich zwei Forschungsfelder gegenseitig als mit demselben Bereich von Phänomen befasst wahrnehmen, wobei ihre methodischen Ansätze und theoretischen Erklärungen jedoch so unterschiedlich sind, dass ein offener Konflikt über die Wahrheit oder Falschheit bestimmter Aussagen oder die Genauigkeit in der Anwendung einer Methode nicht stattfindet. Nichtsdestotrotz streben beide Parteien danach, die maßgebliche Erklärung der entsprechenden Phänomene anzubieten. Indem die erweiterte Gemeinschaft der (...) Forschenden oder die Öffentlichkeit einen Ansatz als maßgeblich anerkennt, handeln sie als eine dritte, gewissermaßen neutrale Partei, die einen Preis vergibt, um den die anderen Parteien konkurrieren. Der Artikel beschreibt das Verhältnis von Genetik und Entwicklungsbiologie um 1900 als epistemische Konkurrenz. Diese Forschungsfelder geben unterschiedliche Erklärungen für die Phänomene der organischen Reproduktion. Die Erklärungen unterscheiden sich bezüglich der Formbegriffe und entsprechend hinsichtlich der Begriffe der Vererbung von Aspekten der Form eines Organismus. Zudem basieren die Erklärungen der beiden Felder auf unterschiedlichen Arten kausalen Schließens, die in unterschiedliche experimentelle Ansätze eingebettet sind. Diese Unterschiede können als Instanzen eines allgemeineren Unterschieds zwischen der Tradition der Naturgeschichte, die sich mit Unterschieden zwischen Organismen auseinandersetzt, und der Tradition der Anatomie, die sich mit den Teilen der Organismen beschäftigt, angesehen werden. Dieses Bild der Genetik und Entwicklungsbiologie als Zweige unterschiedlicher fest verankerter Traditionen widerspricht dem Narrativ der Trennung des Begriffs der Vererbung von dem der Entwicklung im Zuge einer Trennung der Disziplinen der Genetik und der Embryologie, das in der Historiographie der Biologie nach wie vor weit verbreitet ist. (shrink)

Despite several decades of criticism, dichotomous thinking about behavioral development remains widespread and influential. This is particularly true in study of birdsong development, where it has become increasingly common to diagnose songs, elements of songs, or precursors of songs as either innate or learned on the basis of isolation-rearing experiments. The theory of sensory templates has encouraged both the dichotomous approach and an emphasis on structural rather than functional aspects of song development. As a result, potentially important lines of investigation (...) have been overlooked and the interpretation of existing data is often flawed. Evidence for a genetic origin of behavioraldifferencesis frequently interpreted as evidence for the genetic determination of behavioralcharacters. The technique of isolation rearing remains the methodology of choice for many investigators, despite the fact that it offers only a rather crude analysis of the contribution of experience to song development and provides no information at all about genetic contributions to development. The latter could in principle be elucidated by the application of developmental-genetic techniques, but it is unlikely that these can easily be applied to the study of birdsong. Because developmental questions are so often posed in terms of the learned–innate dichotomy, “experience” is taken to be synonymous with “learning” and the possible role of nonobvious contributions to song development has largely been ignored. An alternative approach, based on Daniel Lehrman's interactionist theory of development, permits a more thorough appreciation of the problems that have yet to be addressed, and provides a more secure conceptual foundation for theories of song development. (shrink)

Obesity is the focus of multiple lines of inquiry that have -- together and separately -- produced many deep insights into the physiology of weight gain and maintenance. We examine three such streams of research and show how they are oriented to obesity intervention through multilevel integrated approaches. The first research programme is concerned with the genetics and biochemistry of fat production, and it links metabolism, physiology, endocrinology and neurochemistry. The second account of obesity is developmental and draws (...) together epigenetic and environmental explanations that can be embedded in an evolutionary framework. The third line of research focuses on the role of gut microbes in the production of obesity, and how microbial activities interact with host genetics, development and metabolism. These interwoven explanatory strategies are driven by an orientation to intervention, both for experimental and therapeutic outcomes. We connect the integrative and intervention-oriented aspects of obesity research through a discussion of translation, broadening the concept to capture the dynamic, iterative processes of scientific practice and therapy development. This system-oriented analysis of obesity research expands the philosophical scrutiny of contemporary developments in the biosciences and biomedicine, and has the potential to enrich philosophy of science and medicine. (shrink)

The science of genetics is undergoing a paradigm shift. Recent discoveries, including the activity of retrotransposons, the extent of copy number variations, somatic and chromosomal mosaicism, and the nature of the epigenome as a regulator of DNA expressivity, are challenging a series of dogmas concerning the nature of the genome and the relationship between genotype and phenotype. According to three widely held dogmas, DNA is the unchanging template of heredity, is identical in all the cells and tissues of the (...) body, and is the sole agent of inheritance. Rather than being an unchanging template, DNA appears subject to a good deal of environmentally induced change. Instead of identical DNA in all the cells of the body, somatic mosaicism appears to be the normal human condition. And DNA can no longer be considered the sole agent of inheritance. We now know that the epigenome, which regulates gene expressivity, can be inherited via the germline. These developments are particularly significant for behavior genetics for at least three reasons: First, epigenetic regulation, DNA variability, and somatic mosaicism appear to be particularly prevalent in the human brain and probably are involved in much of human behavior; second, they have important implications for the validity of heritability and gene association studies, the methodologies that largely define the discipline of behavior genetics; and third, they appear to play a critical role in development during the perinatal period and, in particular, in enabling phenotypic plasticity in offspring. I examine one of the central claims to emerge from the use of heritability studies in the behavioral sciences, the principle of minimal shared maternal effects, in light of the growing awareness that the maternal perinatal environment is a critical venue for the exercise of adaptive phenotypic plasticity. This consideration has important implications for both developmental and evolutionary biology. (shrink)

Developmental systems theory (DST) is a wholeheartedly epigenetic approach to development, inheritance and evolution. The developmental system of an organism is the entire matrix of resources that are needed to reproduce the life cycle. The range of developmental resources that are properly described as being inherited, and which are subject to natural selection, is far wider than has traditionally been allowed. Evolution acts on this extended set of developmental resources. From a developmental systems perspective, development (...) does not proceed according to a preformed plan; what is inherited is much more than DNA; and evolution is change not only in gene frequencies, but in entire developmental systems. (shrink)

In the past century, nearly all of the biological sciences have been directly affected by discoveries and developments in genetics, a fast-evolving subject with important theoretical dimensions. In this rich and accessible book, Paul Griffiths and Karola Stotz show how the concept of the gene has evolved and diversified across the many fields that make up modern biology. By examining the molecular biology of the 'environment', they situate genetics in the developmental biology of whole organisms, and reveal (...) how the molecular biosciences have undermined the nature/nurture distinction. Their discussion gives full weight to the revolutionary impacts of molecular biology, while rejecting 'genocentrism' and 'reductionism', and brings the topic right up to date with the philosophical implications of the most recent developments in genetics. Their book will be invaluable for those studying the philosophy of biology, genetics and other life sciences. (shrink)

Developmental biology is a theory of interpretation. Developmental signals are interpreted differently depending on the previous history of the responding cell. Thus, there is a context for the reception of a signal. While this conclusion is obvious during metamorphosis, when a single hormone instructs some cells to proliferate, some cells to differentiate, and other cells to die, it is commonplace during normal development. Paracrine factors such as BMP4 can induce apoptosis, proliferation, or differentiation depending upon the history of (...) the responding cells. In addition, organisms have evolved to alter their development in response to differences in temperature, diet, the presence of predators, or the presence of competitors. This allows them to develop the phenotype, within the limits imposed by the genotype, best suited for the immediate habitat of the organism. Most developing organisms have also evolved to expect developmental signals from symbionts, and these organisms develop abnormally if the symbiont signals are not present. Thus Hoffmeyer’s “vertical semiotic system” of genetic communication and “horizontal semiotic system” of ecological communication are integrated during development. (shrink)

Developmental systems theory is an attempt to sum up the ideas of a research tradition in developmental psychobiology that goes back at least to Daniel Lehrman’s work in the 1950s. It yields a representation of evolution that is quite capable of accommodating the traditional themes of natural selection and also the new results that are emerging from evolutionary developmental biology. But it adds something else - a framework for thinking about development and evolution without the distorting dichotomization (...) of biological processes into gene and non-gene and the vestiges of the ‘black-boxing’ of developmental processes in the modern synthesis, such as the asymmetric use of the concept of information. Phenomena that are marginalized in current gene-centric conceptions, such as extra-genetic inheritance, niche construction and phenotypic plasticity are placed center stage. (shrink)

One foundational question in contemporarybiology is how to `rejoin evolution anddevelopment. The emerging research program(evolutionary developmental biology or`evo-devo) requires a meshing of disciplines,concepts, and explanations that have beendeveloped largely in independence over the pastcentury. In the attempt to comprehend thepresent separation between evolution anddevelopment much attention has been paid to thesplit between genetics and embryology in theearly part of the 20th century with itscodification in the exclusion of embryologyfrom the Modern Synthesis. This encourages acharacterization of evolutionary developmentalbiology as (...) the marriage of evolutionary theoryand embryology via developmental genetics. Butthere remains a largely untold story about thesignificance of morphology and comparativeanatomy (also minimized in the ModernSynthesis). Functional and evolutionarymorphology are critical for understanding thedevelopment of a concept central toevolutionary developmental biology,evolutionary innovation. Highlighting thediscipline of morphology and the concepts ofinnovation and novelty provides an alternativeway of conceptualizing the `evo and the `devoto be synthesized. (shrink)

The concept of innateness is used to make inferences between various better-understood properties, like developmental canalization, evolutionary adaptation, heritability, species-typicality, and so on (‘innateness-related properties’). This article uses a recently-developed account of the representational content carried by inheritance systems like the genome to explain why innateness-related properties cluster together, especially in non-human organisms. Although inferences between innateness-related properties are deductively invalid, and lead to false conclusions in many actual cases, where some aspect of a phenotypic trait develops in reliance (...) on a genetic representation it will tend, better than chance, to have many of the innateness-related properties. The account also shows why inferences between innateness-related properties sometimes fail and argues that such inferences are especially misleading when applied to human psychology and behaviour because human psychological development is especially reliant on non-genetic inherited representations. (shrink)

Developmental Systems Theory (DST) emphasises the importance of non-genetic factors in development and their relevance to evolution. A common, deflationary reaction is that it has long been appreciated that non-genetic factors are causally indispensable. This paper argues that DST can be reformulated to make a more substantive claim: that the special role played by genes is also played by some (but not all) non-genetic resources. That special role is to transmit inherited representations, in the sense of Shea (2007: Biology (...) and Philosophy, 22, 313-331). Formulating DST as the claim that there are non-genetic inherited representations turns it into a striking, empirically-testable hypothesis, driving the sort of investigations that are only now beginning to appear in the scientific literature. DST’s characteristic rejection of a gene vs. environment dichotomy is preserved, but without dissolving all potentially explanatory distinctions into an interactionist causal soup, as some have alleged. (shrink)

Using the evolution of the stickleback family of subarctic fish as a touchstone, we explore the effect of new discoveries about regulatory genetics, developmental plasticity, and epigenetic inheritance on the conceptual foundations of the Modern Evolutionary Synthesis. Identifying the creativity of natural selection as the hallmark of the Modern Synthesis, we show that since its inception its adherents have pursued a variety of research projects that at first seemed to conflict with its principles, but were accommodated. We situate (...) challenges coming from developmental biology in a dialectic between innovation and tradition, suggesting on the basis of past episodes that even if developmental plasticity and epigenetic inheritance are aligned with its principles the Modern Synthesis will be significantly affected. (shrink)