Experimental Systems in the Co-Construction of Scientific Knowledge.

The publication of Toward a History of Epistemic Things 25 years ago was a landmark in science studies. Not only was the book a brilliant overview of new research trends, but it was also a personal and highly original contribution because of its emphasis on the major role of experimental systems in the construction of scientific knowledge. The paths that it opened have not yet been fully explored. More seriously, the ambition of the author to reinforce the value of scientific knowledge by the role of experimental systems in its construction has not been pursued.

A Time to Model and a Time to Experiment.

The nature and role of models have been amply discussed by philosophers of science. They have emphasized the diversity of models and their functions. Biological sciences in general, and molecular and cellular biology in particular, are no exceptions. The nature and role of models in molecular and cellular biology are also a legacy of the different disciplines that contributed to its formation. Models can be a step toward abstraction, or the opposite, a step toward a material representation of an-to date-abstract phenomenon. Models can also help to collect information and knowledge. I will consider different models that played a highly important role in molecular and cellular biology, up to the Gene Regulatory Network model. There is a right time to model, and a right way to do it. I will try to understand why a model is well received (or not), and what kind of relationship it may or must have with experiments and experimental data.

Homage to Eric Davidson.

The Britten-Davidson model of genetic regulation was well received by American molecular biologists and embryologists, but not by the members of the French School of molecular biology. In particular, François Jacob considered it too abstract and too removed from experiments. I re-examine the contrast between the Britten-Davidson model and the operon model by Jacob and Monod, the different scientific contexts in which they were produced and the different roles they played. I also describe my recent encounters with Eric Davidson, and how I discovered the extraordinary continuity of his work on the development of the sea urchin, as well as his rich personality.

Human germline editing: a historical perspective.

The development of the genome editing system called CRISPR-Cas9 has opened a huge debate on the possibility of modifying the human germline. But the types of changes that could and/or ought to be made have not been discussed. To cast some light on this debate, I will describe the story of the CRISPR-Cas9 system. Then, I will briefly review the projects for modification of the human species that were discussed by biologists throughout the twentieth century. Lastly, I will show that for plenty of reasons, both scientific and societal, germline modification is no longer a priority for our societies.

Introduction: Eric Davidson and the molecular biology of evolution and development.

Between November 30th and December 2nd, 2015, the Jacques Loeb Centre for the History and Philosophy of the Life Sciences at Ben-Gurion University of the Negev in Beer Sheva (Israel) held its Eighth International Workshop under the title "From Genome to Gene: Causality, Synthesis and Evolution". Eric Davidson, the founder of the concept of developmental Gene Regulatory Networks, had regularly attended the previous meetings, and his participation in this one was expected, but he suddenly passed away 3 months before. In this paper, we provide an introduction and overview on five papers that were presented at the workshop and examine the importance of genomes and gene regulatory networks in extant biology, developmental biology, evolutionary biology and medicine, as well as a collection of remembrances of Eric Davidson, of his personality as well as of his scientific contributions. Historical perspectives are provided, and the ethical issues raised by the new tools developed to modify the genome are also discussed.

Genetic modification of the human germ line: The reasons why this project has no future.

Modification of the human germ line has remained a distant but valuable objective for most biologists since the emergence of genetics (and even before). To study the historical transformations of this project, I have selected three periods - the 1930s, at the pinnacle of eugenics, around 1974 when molecular biology triumphed, and today - and have adopted three criteria to estimate the feasibility of this project: the state of scientific knowledge, the existence of suitable tools, and societal demands. Although the long-awaited techniques to modify the germ line are now available, I will show that most of the expectations behind this project have disappeared, or are considered as being reachable by highly different strategies.

Monod and the spirit of molecular biology.

The founders of molecular biology shared views on the place of biology within science, as well as on the relations of molecular biology to Darwinism. Jacques Monod was no exception, but the study of his writings is particularly interesting because he expressed his point of view very clearly and pushed the implications of some of his choices further than most of his contemporaries. The spirit of molecular biology is no longer the same as in the 1960s but, interestingly, Monod anticipated some recent evolutions of this discipline.

Pseudoalleles and Gene Complexes: The Search for the Elusive Link Between Genome Structure and Gene Function.

After their discovery in the first decades of the 20th century, pseudo-alleles generated much interest among geneticists, because they apparently violated the conception of the genome as a collection of independent genes, a view elaborated by Thomas Morgan's group. This article focuses on two issues: the way the phenomenon of pseudoallelism suggests that the genome is more than a simple addition of independent genes, and the connection established between the formation of pseudoalleles during evolution and their functional roles. The article discusses the first explanations for the origin of pseudoalleles elaborated in the mid-1930s, the metabolic/developmental sequential model proposed by Ed Lewis in the 1950s, the disappointments encountered with the T-complex in the 1970s, and the fading of the previous models after the molecular characterization of the pseudoallelic gene complexes in the 1980s. Genomes are more than collections of genes, but their structures are the result of a complex evolutionary history that leaves no place for simplistic models.