Abstract

This paper examines the process that led to the identification of chromosomes as carriers of genes. It focuses on the role played by explanations in theory construction and analyzes the status given to the entities and processes introduced through such explanations. I argue that the theory of the gene was a functional explanation that, as such, could not offer decisive support for the existence of genes. However, I maintain that functional explanations set the conditions of identification needed to discover the physical structure that has a certain function in a given system. In this case, the theory of the gene helped to select the chromosomes as the physical structure responsible for the Mendelian segregation of genes. In its turn, the theory of chromosome inheritance helped to reduce the permissive character of the theory of the gene, regulating its further development.