Jean Gayon

The singular fate of genetics in the history of French biology, 1900–1940

ConclusionIn this study we have examined the reception of Mendelism in France from 1900 to 1940, and the place of some of the extra-Mendelian traditions of research that contributed to the development of genetics in France after World War II. Our major findings are:(1)Mendelism was widely disseminated in France and thoroughly understood by many French biologists from 1900 on. With the notable exception of Lucien Cuénot, however, there were few fundamental contributions to the Mendelian tradition, and virtually none from about 1915 to the midthirties. Prior to 1900, Cuénots work was already marked by a striking interest in physiological mechanisms; his physiological preoccupations played a considerable role in his account of the inheritance of coat color and of susceptibility to tumors in mice. His analysis of the roles of the many genes involved in pigment formation was developed with an eye to one of the first models of the metabolic reactions involved. It yielded one of the earliest suggestions that the steps controlled by single genes involve enzymes as the products of genes.(2)The inflexible structure of the French universities played an important role in discouraging research in genetics and in the failure to train the post-World War I generation in that discipline.(3)During this period the disciplines of physiology, microbiology, and causal embryology were dominant in French experimental biology. The issues that were most prominent within these disciplines—differentiation and development, regulation of growth and morphology, infection and assimilation—were not easily treated within genetics. The failure of Mendelism to resolve a variety of legitimate explanatory issues to the satisfaction of serious investigators trained in the dominant French disciplines also contributed to the failure of Mendelism to penetrate French science. The violent anti-Mendelian polemics put forward by many of the most committed neo-Lamarckians raised many of the same issues regarding the supposed insufficiency of Mendelism. Cuénots reluctance to encourage his students to pursue careers in genetics illustrates the compound nature of the resistance. Despite the absence of a developed tradition of Mendelian research, a French school of molecular genetics had developed by the 1950s. It flourished outside the university system at the Institut Pasteur, the Institut de Biologie physico-chimique, and the CNRS (though some of its leading figures had university connections), and it was only beginning to enter into university curricula. The most important indigenous research that informed the new tradition was that of Eugène Wollman on “paraheredity” of phage infection and lysogeny, of André Lwoff on the physiology and nutritional requirements of protozoa and bacteria, and the embryologically influenced genetic investigations of Boris Ephrussi. The conceptual and methodological resources of the French school were enriched by this background; a full understanding of the products of the fifties, we believe, requires a proper appreciation of these antecedents. Molecular genetics in France grew out of the Pasteurian tradition of microbiology and the highly developed tradition of causal embryology as modified by Ephrussi. Both of these traditions were extra-Mendelian and not anti-Mendelian, but they both shared a number of the problems and assumptions that were at the center of the extremist resistance to Mendelism. In many respects, then, it is more fruitful to see the entry of French biology into molecular genetics as a development of its microbial-physiological and causal-embryological traditions, coopting the tools and techniques of genetics, rather than the other way around.

The Role of the Vilmorin Company in the Promotion and Diffusion of the Experimental Science of Heredity in France, 1840–1920

Institutions in the commercial sector, especially those marketing seeds for agricultural use, have long had an interest in understanding heredity. Much of what we know of this relationship concerns the period since the rediscovery of Mendels work in 1900. Little is known of the nature of this relationship in the nineteenth century. In this paper, we will focus on the role played by one company - the Vilmorin Company in France - in the promotion of an experimental science of heredity from 1840 to 1920.

Defining Life: Synthesis and Conclusions

The first part of the paper offers philosophical landmarks on the general issue of defining life. §1 defends that the recognition of “life” has always been and remains primarily an intuitive process, for the scientist as for the layperson. However we should not expect, then, to be able to draw a definition from this original experience, because our cognitive apparatus has not been primarily designed for this. §2 is about definitions in general. Two kinds of definition should be carefully distinguished: lexical definitions (based upon current uses of a word), and stipulative or legislative definitions, which deliberately assign a meaning to a word, for the purpose of clarifying scientific or philosophical arguments. The present volume provides examples of these two kinds of definitions. §3 examines three traditional philosophical definitions of life, all of which have been elaborated prior to the emergence of biology as a specific scientific discipline: life as animation (Aristotle), life as mechanism, and life as organization (Kant). All three concepts constitute a common heritage that structures in depth a good deal of our cultural intuitions and vocabulary any time we try to think about “life”. The present volume offers examples of these three concepts in contemporary scientific discourse. The second part of the paper proposes a synthesis of the major debates developed in this volume. Three major questions have been discussed. A first issue (§4) is whether we should define life or not, and why. Most authors are skeptical about the possibility of defining life in a strong way, although all admit that criteria are useful in contexts such as exobiology, artificial life and the origins of life. §5 examines the possible kinds of definitions of life presented in the volume. Those authors who have explicitly defended that a definition of life is needed, can be classified into two categories. The first category (or standard view) refers to two conditions: individual self-maintenance and the open-ended evolution of a collection of similar entities. The other category refuse to include reproduction and evolution, and take a sort of psychic view of the living. §6 examines the relationship between the question of the definition of life and that of the origins of life. There is a close parallel between the general conceptions of the origins of life and the definitions of life.

The individuality of the species: A Darwinian theory? — from Buffon to Ghiselin, and back to Darwin

Since the 1970s, there has been a tremendous amount of literature on Ghiselins proposal that “species are individuals”. After recalling the origins and stakes of this thesis in contemporary evolutionary theory, I show that it can also be found in the writings of the French naturalist Buffon in the 18th Century. Although Buffon did not have the conception that one species could be derived from another, there is an interesting similarity between the modern argument and that of Buffon regarding the “individuality of species’. The analogy is strong enough to force us to recognize that genuine evolutionary (or Darwinian) questions might be of secondary importance in the discussion. In consequence, the third section of the paper proposes an alternative schema for the “logical structure” of the Darwinian concept of species. Darwin distinguished the problem of the designation of a concrete species, and the problem of its signification of species within his theory of descent? The resulting notion of species involves a logical structure based on the fusion of the logical operations of classification and ordering. The difficulty — and interest — is that this interpretation of species does not entail any precise operational definition of species; it can only tell us what the ultimate signification of classification is within the theory of descent with modification through natural selection.

Boris Ephrussi and the Synthesis of Genetics and Embryology

The career of Boris Ephrussi (1901–1979) presents a series of fascinating perspectives on the intellectual and sociological difficulties that plagued those who wished to reconcile genetics and embryology during the middle of this century (2–8). Ephrussi was born in a suburb of Moscow, but spent much of his working career in France, with important periods in the United States. He made major contributions to the rapprochement between genetics and developmental biology. His work, which we believe has been undervalued both by historians of biology and by subsequent generations of biologists, is worth studying for at least three reasons: 1. Throughout his long career, he sought an adequate causal analysis of differentiation and development. Relatively early, he saw the need to accomplish this task by uniting the findings of genetics with those of embryology. To this end, he employed a great variety of experimental organisms and techniques and explored numerous conceptual and theoretical models. Accordingly, the study of his work provides considerable insight into the shifts in theory and technique that affected various attempts to come to grips with the problems of differentiation, development, and morphogenesis while maintaining consistency—and serious contact—with genetics. 2. Because he worked in both European and American settings and maintained extremely rich contacts with workers in numerous disciplines on both sides of the Atlantic, his career sheds light on the various integrative efforts—and tensions—that characterize the relationship between embryology and genetics during the middle of the century. He was intellectually central to a number of key debates, a proponent of an integrative view of the organism that, at times, left him at odds with his colleagues in genetics, a prime mover in the institutionalization of genetics in France, and closely involved with institutional developments elsewhere that reconfigured the map of biology. 3. Ephrussi and his co-workers pioneered a variety of experimental approaches to the analysis of the roles of nuclear and cytoplasmic factors in differentiation. They helped shape the transition from Mendelian transmission genetics to molecular genetics and influenced the transition from embryology to developmental biology.

Defining Life: conference proceedings.

There is a long tradition of software simulations in theoretical biology to complement pure analytical mathematics which are often limited to reproduce and understand the self-organization phenomena resulting from the non-linear and spatially grounded interactions of the huge number of diverse biological objects. Since John Von Neumann and Alan Turing pioneering works on self-replication and morphogenesis, proponents of artificial life have chosen to resolutely neglecting a lot of materialistic and quantitative information deemed not indispensable and have focused on the rule-based mechanisms making life possible, supposedly neutral with respect to their underlying material embodiment. Minimal life begins at the intersection of a series of processes which need to be isolated, differentiated and duplicated as such in computers. Only software developments and running make possible to understand the way these processes are intimately interconnected in order for life to appear at the crossroad. In this paper, I will attempt to set out the history of life as the disciples of artificial life understand it, by placing these different lessons on a temporal and causal axis, showing which one is indispensable to the appearance of the next and how does it connect to the next. I will discuss the task of artificial life as setting up experimental software platforms where these different lessons, whether taken in isolation or together, are tested, simulated, and, more systematically, analyzed. I will sketch some of these existing software platforms: chemical reaction networks, Varela’s autopoietic cellular automata, Ganti’s chemoton model, whose running delivers interesting take home messages to open-minded biologists.

THE CONCEPT OF THE GENE IN CONTEMPORARY BIOLOGY: CONTINUITY OR DISSOLUTION?

“Gene” is a theoretical term. Like all theoretical terms, it applies to many different domains of research. Like all theoretical terms, its meaning has dramatically changed over and over in time, and it has been defined in so many different operational ways. The problem is that the descriptive content of the various definitions of the genes that exist do not coincide. This paper provides a general evaluation of this situation. Firstly it shows that the theoretical concepts of classical genetics cannot be correlated unambiguously with the theoretical concepts of molecular genetics. In fact, there is no agreement on such simple questions as: Where are the genes? When do they exist? What are they? How many? Secondly, it provides an interpretation of why biologists continue to use the word ‘gene’. Three complementary explanations are proposed: scientific communication, economical stakes, and struggle for scientific authority among biological disciplines

The Contributions – and Collapse – of Lamarckian Heredity in Pasteurian Molecular Biology: 1. Lysogeny, 1900–1960

This article shows how Lamarckism was essential in the birth of the French school of molecular biology. We argue that the concept of inheritance of acquired characters positively shaped debates surrounding bacteriophagy and lysogeny in the Pasteurian tradition during the interwar period. During this period the typical Lamarckian account of heredity treated it as the continuation of protoplasmic physiology in daughter cells. Félix d’Hérelle applied this conception to argue that there was only one species of bacteriophage and Jules Bordet applied it to develop an account of bacteriophagy as a transmissible form of autolysis and to analyze the new phenomenon of lysogeny. In a long-standing controversy with Bordet, Eugène Wollman deployed a more morphological understanding of the inheritance of acquired characters, yielding a particulate, but still Lamarckian, account of lysogeny. We then turn to André Lwoff who, with several colleagues, completed Wollman’s research program from 1949 to 1953. We examine how he gradually set aside the Lamarckian background, finally removing inheritance of acquired characters from the resulting account of bacteriophagy and lysogeny. In the conclusion, we emphasize the complex dual role of Lamarckism as it moved from an assumed explanatory framework to a challenge that the nascent molecular biology had to overcome.

The “Paramount Power of Selection”: From Darwin to Kauffman

For approximately two decades now, the Darwinian interpretation of evolution has now been challenged in many ways. Modern criticisms make it difficult, even for the staunchest Darwinians, not to take a distance from Darwin’s bold phrases on the “power” of natural selection. Let me remind you of some famous declarations of Darwin on the subject: “It may be said that natural selection is daily and hourly scrutinising, throughout the world, every variation, even the slightest; rejecting that which is bad, preserving and adding up all that is good; silently and insensibly working, whenever and wherever opportunity offers, at the improvement of each organic being in relation to its organic and inorganic conditions of life”.1 “What limit can be put to this power, acting during long ages and rigidly scrutinising the whole constitution, structure and habits of each creature,—favouring the good and rejecting the bad? I can see no limit to this power, in slowly and beautifully adapting each form to the most complex relations of life. The theory of natural selection, even if we looked no further than this, seems to me to be in itself probable”.2 “The long-continued accumulation of beneficial variations will infallibly have led to structures as diversified, as beautifully adapted for various purposes and as excellently co-ordinated, as we see in the animals and plants around us. Hence I have spoken of selection as the paramount power, whether applied by man to the formation of domestic breeds, or by nature to the production of species”.3

Does Oxygen Have a Function, or Where Should the Regress of Functional Ascriptions Stop in Biology?

Biologists apply the notion of function to almost every type of structure and process that enters into descriptions of biological phenomena. They can also generate alarmingly long regresses: x can be the function of y, which is the function of z … and so on. But the functional regress must stop somewhere. This chapter investigates whether the philosophical theories restrict the regress of functional attributions by asking if they legitimate making such attributions to structures at elementary levels of organization (atoms and elementary molecules) and to structures at higher ones (organisms and species). First, I propose a classification of the current theories of functions into three categories, rather than the usual two: Larry Wright’s “etilogical theory” is definetly something different from the “selective etiological theories” that have been developed after him. Then I examine whether these theories can admit or not the ascription of functions to very low or very hig levels of organization. At the most elementary levels, functional ascriptions are unacceptable for the selective etiological theory of functions, because atoms or elementary molecules are not units of selection; they are less problematic for the systemic theory of functions, and also for Wright’s original “etiological theory,” provided that the composition and behavior of the parts constituting the system involved are precisely stated. At the level of organisms and species, functional ascriptions are possible within both the selective etiological and the systemic theory, but this will heavily depend on the theoretical framework involved in both cases. These limit cases show that the selective conceptions of functions are less tolerant than the systemic ones. They also suggest, as already noted by William Wimsatt, that functions are more convincingly ascribed to processes than to structural entities.