The era of epigenetics (original) (raw)
Related papers
Synthesizing embryology and human genetics: paradigms regained
American journal of human genetics, 1992
The only way to get from genotype to phenotype is through development, so nearly all mutations can be seen as affecting developmental processes. Whether a gene encodes a protein needed for limb morphogenesis or for the color of the iris, the effect is developmental. Indeed, a century ago, genetics and embryology were considered to be the same thing. However, within the ranks of fin de siecle physiological embryologists, a problem arose as to which compartment of the zygote-the nucleus or the cytoplasm-contained the hereditary-developmental potentials. Scientists such as T. Boveri and E. B. Wilson claimed that the nucleus carried the potentials, while other embryologists, such as T. H. Morgan, claimed that these inherited potencies lay within the cytoplasm (for details, see Gilbert 1979). This conflict formed the basis for the emergence of genetics out of embryology. Study of the X chromosome led from embryology to genetics. The correlation between nuclear karyotype and organismal phenotype strongly suggested that the number of X chromosomes determined sexi.e., the nucleus contained the potentials (Stevens 1905a, 1905b; Wilson 1905a, 1905b). Morgan's research, first on parthenogenetic hickory aphids and later on Drosophila, began as an attempt to disprove that hypothesis. Instead, he reluctantly confirmed it. In doing so, he and his laboratory established the gene theory and set genetics on a course that diverged from embryology. By 1926, Morgan claimed that in the past a lot of confusion had resulted "from confusing the prob
Structures and Norms in Science, Dordrecht: …, 1997
Embryology and Evolution 1920-1960: Worlds Apart
During the early part of the 20th century most embryologists were skeptical about the significance of Mendelian genetics to embryological development. A few embryologists began to study the developmental effects of Mendelian genes around 1940. Such work was a necessary step on the path to modern developmental biology. It occurred during the time when the Evolutionary Synthesis was integrating Mendelian and population genetics into a unified evolutionary theory. Why did the first embryological geneticists begin their study at that particular time? One possible explanation is that developmental genetics was a potential avenue of alliance between embryology and evolutionary biology, two fields that had been separated since the 1890s. To assess this possible motive it is necessary to explore the methodological contrasts that obtained between embryology and both Mendelian-chromosomal genetics and neo-Darwinian evolutionary theory. Some of these contrasts persist to the present day.
Special Issue 'Sketches for a conceptual history of epigenesis'
Hist. and Phil. of the Life Sciences
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
CAPE Studies in Applied Philosophy and Ethics Series
Overlooked elements in the history of evo-devo 40 2003; Carroll 2005) and comparative studies (Love and Raff 2003). For instance, Love and Raff (2003) argue that we should look not only at developmental genetics but also at comparative embryology, morphology and paleontology because the techniques and tools used in evo-devo today had been created in the tradition of developmental genetics, and the research problem including the relationship between evolution and development in evo-devo had long been studied in the latter disciplines. The second trend is the consideration of individual contributions by pioneers of evo-devo such as Haeckel, Goldschmidt, Waddington and so on (e.g., Laubichler and Maienschein 2007). Although the previous historical studies have focused on a long-term history from 1880s to 1990s or some pioneers' works, they have not paid much attention to the 80s. Some researches mention the challenges to the modern synthesis offered by diverse disciplines (e.g., paleontology, morphology, comparative embryology, and developmental biology) around the 80s and emphasize the importance of developmental genetics, which is said to have brought together the diverse movements and laid the foundation for evo-devo (Love and Raff 2003; Laubichler 2009, 2010). However, more detailed analyses of the 80s are needed because it was the era just prior to the birth of evo-devo 1 and therefore it is important in the prehistory of evo-devo. Thus by focusing on the 80s, the present study intends to make up the lack of the previous studies. Empirical studies on epigenetics: Methodological integration and non-gene-centered framework This section summarizes some empirical works of the anti-gene-centrism such as researches by Alberch, Hall, and Müller, emphasizing the role of non-genetic developmental processes and integrating the methodology of experimental embryology and comparative studies. Before examining them, however, we clarify the word "antigene-centrism" and the concept "epigenetics," which was emphasized by the anti-genecentrists. What are epigenetics and the anti-gene-centrism? The concept of "epigenetics" was coined by Waddington (1942) and it originally The inference from developmental mechanisms to evolutionary processes. American Zoology 40: 819-831.
The Evolution of Views on Embryology
Metascience, 2007
Ron Amundson is both an historian and a philosopher of biology and has done research work that requires such a double ability. In this book, he forces us to look at biology as a whole -history, science, and epistemological models -and calls for a new equilibrium to be achieved by a revision of certain basic tenets that shaped neo-Darwinian biology in the 20th century. The subtitle of his book, Roots of Evo-Devo, and the title of the first section, ''Evo-devo as a new and old science'' shows that a synthetic model, encompassing evolutionary and developmental biology, is the key to such a new equilibrium and that the model is not a recent creation. Actually, it dates back before the neo-Darwinian synthesis. I think the historical framework Amundson has devised can have a part in this project and he has also designed an insightful philosophical plan of his own.
2014
The origin of epigenetics has been traditionally traced back to Conrad Hal Waddington's foundational work in 1940s. The aim of the present paper is to reveal a hidden history of epigenetics, by means of a multicenter approach. Our analysis shows that genetics and embryology in early XX century--far from being non-communicating vessels--shared similar questions, as epitomized by Thomas Hunt Morgan's works. Such questions were rooted in the theory of epigenesis and set the scene for the development of epigenetics. Since the 1950s, the contribution of key scientists (Mary Lyon and Eduardo Scarano), as well as the discussions at the international conference of Gif-sur-Yvette (1957) paved the way for three fundamental shifts of focus: 1. From the whole embryo to the gene; 2. From the gene to the complex extranuclear processes of development; 3. From cytoplasmic inheritance to the epigenetics mechanisms.
The American Development of Biology, 1988
Reflecting on embryology in the 1930s, Johannes Holtfreter stated: We managed more or less successfully to keep our work undisturbed by humanity's strife and struggle around us and proceeded to study the plants and animals, and particularly, the secrets of amphibian development. Here, at least, in the realm of undespoiled Nature, everything seemed peaceful and in perfect order. It was from our growing intimacy with the inner harmony, the meaningfulness, the integration, and the interdependence of the structures and functions as we observed them in dumb creatures that we derived our own philosophy of life. It has served us well in this continuously troublesome world.' The attempts to reintegrate embryology and genetics during the last years of the 1930s represent the last chapter in the emergence of American biology. When had American biology finished "emerging"? I suspect that stage was reached when it had successfully resisted the last attempts to reintegrate it into European-dominated traditions of inquiry. For genetics, this occurred in the late 1930s when Richard B. Goldschmidt and Ernest Everett Just separately countered the American school of genetics with European alternatives. Goldschmidt and Just both attempted to place genetics into a physiological framework. Goldschmidt was the director of the genetics section of the Kaiser Wilhelm Institute before fleeing the Nazis and coming to America in 1936. For Goldschmidt, the "static genetics" of Τ. H. Morgan, centered on individual particulate genes, was to be replaced by "physiological genetics" wherein the gene did not exist as an individual unit, and its activity, not its location, was the focus of research.
1988
Reflecting on embryology in the 1930s, Johannes Holtfreter stated: We managed more or less successfully to keep our work undisturbed by humanity's strife and struggle around us and proceeded to study the plants and animals, and particularly, the secrets of amphibian development. Here, at least, in the realm of undespoiled Nature, everything seemed peaceful and in perfect order. It was from our growing intimacy with the inner harmony, the meaningfulness, the integration, and the interdependence of the structures and functions as we observed them in dumb creatures that we derived our own philosophy of life. It has served us well in this continuously troublesome world.' The attempts to reintegrate embryology and genetics during the last years of the 1930s represent the last chapter in the emergence of American biology. When had American biology finished "emerging"? I suspect that stage was reached when it had successfully resisted the last attempts to reintegrate it into European-dominated traditions of inquiry. For genetics, this occurred in the late 1930s when Richard B. Goldschmidt and Ernest Everett Just separately countered the American school of genetics with European alternatives. Goldschmidt and Just both attempted to place genetics into a physiological framework. Goldschmidt was the director of the genetics section of the Kaiser Wilhelm Institute before fleeing the Nazis and coming to America in 1936. For Goldschmidt, the "static genetics" of Τ. H. Morgan, centered on individual particulate genes, was to be replaced by "physiological genetics" wherein the gene did not exist as an individual unit, and its activity, not its location, was the focus of research.