A crucial question for anyone willing to defend a process view of the biological world is how to identify a process and how to follow it through time. Here I suggest that the " genidentity " view (suggested first by psychologist Kurt Lewin, and then further explored by philosopher Hans Reichenbach, mainly in the context of physics) can contribute decisively to this project. According to the genidentity view, the identity through time of an entity X is nothing more than the continuous connection of the states through which X goes. In this paper, I explain how the genidentity view addresses the long debated problem of what constitutes diachronic identity in the biological world. I describe the centrality of the concept of genidentity in David Hull's reflection on biological identity, and I then suggest an extension of Hull's view on the basis of recent data demonstrating the ubiquity of symbiotic interactions in the living world. Finally, using immunological interactions as a key example, I show that the genidentity view sheds light on process biology by suggesting that the main interest of a process approach is epistemological rather than ontological, and that the main claim of a process approach is one of priority, that is, the claim that processes precede and define things, and not vice versa.