Broadly speaking, there are two kinds of gene concepts. In this brief chapter, I offer a modest account of each. I seek to show that both are legitimate and that it is necessary to understand their interplay to understand the history of genetics and a number of current issues in genetics. I argue that the first kind of concept makes sense of the conceptual continuities in the history of genetics but yields concepts that are too generic or schematic to specify adequately what is referred to by “the” gene concept and allied concepts. I show that we cannot do without such generic or schematic concepts. Indeed, without schematic concept(s) of the gene, there would be no such discipline as genetics; however, without supplementation by more specific gene concepts, the schematic concepts do not suffice for specifying the reference of the term “gene” – indeed, they do not specify what genes are well enough to ensure that the term refers successfully at all. In less philosophical language, these schematic concepts are impotent to specify exactly what we are talking about when we talk about genes.

The second kind of gene concept, in contrast, yields specific gene concepts but does so at the price of conceptual discontinuity. I argue that if one restricts oneself to the series of discontinuous gene concepts, the findings of molecular genetics favor abandoning a univocal and specific concept of the gene altogether in favor of a pair of concepts: the concept of genetic material plus that of the expression of genetic information.