Vmn1r51 (vomeronasal 1 receptor 51; also called VN12) is a member of the vomeronasal organ V1R gene family, whose activation is believed to be involved with pheromone detection. These mice co-express tau-lacZ with pheromone receptor Vmn1r51 (vomeronasal 1 receptor 51; also called VN12) enabling the analysis of sensory neuron projection patterns. This strain provides insight on the workings of olfactory coding in the vomeronasal system. Analysis of whole mounts of the nasal cavity dissected from adult homozygous mice reveals a subpopulation of vomeronasal sensory neurons whose dendrites, cell bodies, and axons display intense blue color after staining with X-gal.