Research collaboration in co-inventor networks: combining closure, bridging and proximities, Regional Studies. This paper investigates the determinants of co-inventor tie formation using micro-data on genomic patents from 1990 to 2006 in France. In a single analysis, it considers the relational and proximity perspectives that are usually treated separately. In order to do so, it analyses various forms of proximity as alternative driving forces behind network ties that occur within existing components (that is, closure ties) as well as those between two distinct components (that is, bridging ties). Thus, the paper investigates not only the respective impacts of network and proximity determinants, but also how they overlap, interact and possibly act as substitutes or complements.