Ce texte a déjà paru dans Recherches en didactique des sciences et des technologies, N° 4, 2012. Nous remercions Maryline Coquidé, Michèle Dell'Angelo, Stanislas Dorey, Corinne Fortin, Magali Gallezot, Sandrine Henocq, Faouzia Kalali, Jean-Marc Lange, Guy Rumelhard et la RDST de nous avoir autorisé à le reproduire ici. Résumé : Les travaux de la biologie intégrative remettent en cause le déterminisme strict de l'organisation spatiale et temporelle du vivant. Ce texte, travail collectif de notre (...) - Biologie – Nouvel article.

This paper discussses various concepts of biological information with particular attention being paid to genetic information.

In 1957, Francis Crick outlined a startling vision of life in which the great diversity of forms and shapes of macromolecules was encoded in the one-dimensional sequence of nucleic acids. This paper situates Crick's new vision in the debates of the 1950s about protein synthesis and gene action. After exploring the reception of Crick's ideas, it shows how they differed radically from a different model of protein synthesis which enjoyed wide currency in that decade. In this alternative model, advocated by (...) Linus Pauling and other luminaries, three-dimensional templates directed the folding of proteins. Even though it was always considered somewhat speculative, this theory was supported by a number of empirical results originating in different experimental systems. It was eventually replaced by a model in which the forms and shapes of macromolecules resulted solely from their amino acid sequence, dramatically simplifying the problem of protein synthesis which Crick was attempting to solve in 1957. (shrink)

François Jacob is known as one of the key figures in the history of molecular biology. His elaboration, together with Jacques Monod, of the operon model and the basic features of the regulation of gene expression in bacteria, as well as the concept of genetic messenger, won him the Nobel Prize in 1965. Both notions were decisive for the novel imagery of molecular genetics in which the notion of information came to stand central. From a close reading, this article tries (...) to reconstruct how the new language of molecular genetics took shape in the scientific writings of Jacob. In particular, it analyzes how the notions of regulation, information, and language came to be articulated, and how this articulation changed and underwent modulations over time. It shows that a scientific language consists of several layers and thus, as a rule, forms a hybrid structure. The time span covered reaches from the early experiments done together with Monod and Arthur Pardee between 1958 and 1960, also known as the “PaJaMo” experiment, to Jacob’s book on the history of heredity, The Logic of Life, which appeared in 1970. (shrink)

Introduction 1) Une épistémologie non fondationnelle § 1. Concernant l?usage philosophique de l?adjectif « vital », on s?attend à voir surgir une distinction entre le vivant et le vécu, comme si d?emblée nous pouvions et devions accepter que le vital soit aussi quelque chose d?éprouvé par la conscience, par opposition au vivant qui serait simplement observé et expliqué par la science. Pourquoi, dès lors, faudrait-il rechercher dans ou chez les êtres vivants quelque chose de vital ? Cela ne reviendrait-il pas (...) à multiplier les entités et à transformer subrepticement le prédicat « vivant » en être ? Cela ne nous engagerait-t-il pas vers une substantialisation de la vie érigée ainsi en réalité métaphysique ? N?est-ce pas justement le défaut des vitalistes comme Bergson (1907) ou Driesch, de créer un tel processus de surdétermination (Mayr, 1961 ; Kim, 1993, 1998) par et à travers lequel, à un phénomène inconnu X devrait correspondre en même temps des causes observables X?, X?? et une force vitale inobservable Y ? Ce processus introduirait ainsi une entité supra­naturelle dans le cours des événements naturels et rendrait impossible toute forme de stabilité et de généralité pour la relation associant X à X?, X?? et X???. § 2. Nous allons pourtant partir d?une position épistémologique in­édite. Il n?est pas question pour nous d?imposer d?emblée aux biologistes l?existence. (shrink)

The chemical characterization of the substance responsible for the phenomenon of “transformation” of pneumococci was presented in the now famous 1944 paper by Avery, MacLeod, and McCarty. Reception of this work was mixed. Although interpreting their results as evidence that deoxyribonucleic acid (DNA) is the molecule responsible for genetic changes was, at the time, controversial, this paper has been retrospectively celebrated as providing such evidence. The mixed and changing assessment of the evidence presented in the paper was due to the (...) work’s interpretive flexibility – the evidence was interpreted in various ways, and such interpretations were justified given the neophytic state of molecular biology and methodological limitations of Avery’s transformation studies. I argue that the changing context in which the evidence presented by Avery’s group was interpreted partly explains the vicissitudes of the assessments of the evidence. Two less compelling explanations of the reception are a myth-making account and an appeal to the wartime historical context of its publication. (shrink)