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 discipline