Commentary: The epigenotype--a dynamic network view of development (original) (raw)
Related papers
Waddington’s epigenetics or the pictorial meetings of development and genetics
In 1956, in his Principles of Embryology, Conrad Hal Waddington explained that the word “epigenetics” should be used to translate and update Wilhelm Roux’ German notion of “Entwicklungsmechanik” (1890) to qualify the studies focusing on the mechanisms of development. When Waddington mentioned it in 1956, the notion of epigenetics was not yet popular, as it would become from the 1980s. However, Waddington referred first to the notion in the late 1930s. While his late allusion clearly reveals that Waddington readily associated the notion of epigenetics with the developmental process, in the contemporary uses of the notion this developmental connotation seems to have disappeared. The advent and success of molecular biology have probably contributed to focusing biologists’ attention on the “genetic” or the “non-genetic” over the “developmental”. In the present paper, I first examine the links that exist, in Waddington’s work, between the classical notion of epigenesis in embryology and those of epigenetics that Waddington proposed to connect, and even synthesize, data both from embryology and genetics. Second, I show that Waddington’s own view of epigenetics has changed over time and I analyze how these changes appear through his many representations (both schematic or metaphorical images) of the relationships between genetic signals and developmental processes.
The Nurture of Nature: Hereditary Plasticity in Evolution
Philosophical Psychology, 2008
During the late 1930s and the early 1940s, a particularly productive period in his scientific life, Conrad Hal Waddington (1905-75) started to construct a new synthesis between genetics, embryology and evolution. In the 4 years between 1939 and 1943, before he became involved in military activity during the Second World War, he published two substantial books and several seminal papers, all of which were explicitly geared towards constructing of an integrated view of biology. 'The Epigenotype', 1 published in 1942 in the semi-popular science journal Endeavour, is one of these papers. In it, Waddington presented and developed some of the ideas that he had already discussed in his books, and also defined, albeit informally, a new domain of research, epigenetics-the study of the causal mechanisms intervening between the genotype and the phenotype.
From epigenesis to epigenetics: the case of C. H. Waddington
Annals of the New York Academy of Sciences, 2003
One continuous thread in this volume is the name of Conrad H. Waddington , the developmental biologist known as the inventor of the term epigenetics. After some biographical notes on his life, this article explores the meaning of the Waddingtonian equation and the context wherein it was developed. This equation holds that epigenesis + genetics = epigenetics, and refers in retrospect to the debate on epigenesis versus preformationism in neoclassical embryology. Whereas Waddington actualized this debate by linking epigenesis to developmental biology and preformation to genetics, thereby stressing the importance of genetic action in causal embryology, today's epigenetics more and more offers the possibility to enfeeble biological thinking in terms of genes only, as it expands the gene-centric view in biology by introducing a flexible and pragmatically oriented hierarchy of crucial genomic contexts that go beyond the organism.
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.
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
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.
Epigenetics: The origins and evolution of a fashionable topic
The term " epigenetics " was introduced in 1942 by embryologist Conrad Waddington, who, relating it to the 17th century concept of " epigenesis ", defined it as the complex of developmental processes between the genotype and phenotype. While in the years that followed, these processes – in particular gene regulation – were tackled, not in the frame of epigenetics but of genetics, research labelled " epigenetics " rose strongly only in the 21st century. Then it consisted of research on chromatin modifications, i.e. chemical modifications of DNA or histone proteins around DNA that do not change the base sequence. This rise was accompanied by far-reaching claims, such as that epigenetics provides a mechanism for " Lamarckian " inheritance. This article highlights the origin of epigenetics, the major phases of epigenetic research, and the changes in the meaning of the term. It also calls into question some of the far-reaching claims that have accompanied the recent rise of epigenetics.