title: Origin and evolution of the vertebrate vomeronasal system viewed through system-specific genes.
abstract: Tetrapods have two distinct nasal chemosensory systems, the main olfactory system and the vomeronasal system (VNS). Defined by certain morphological components, the main olfactory system is present in all groups of vertebrates, while the VNS is found only in tetrapods. Previous attempts to identify a VNS precursor in teleost fish were limited by functional and morphological characters that could not clearly distinguish between homologous and analogous systems. In the past decade, several genes that specifically function in the VNS have been discovered. Here we first describe recent evolutionary studies of mammalian VNS-specific genes. We then review evidence showing the presence and tissue-specific expression of the VNS-specific genes in teleosts, as well as co-expression patterns of these genes in specific regions of the teleost olfactory epithelium. We propose that a VNS precursor exists in teleosts and that its evolutionary origin predated the separation between teleosts and tetrapods.
authors.affiliation: Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA.
authors.forename: Wendy E
authors.initials: WE
authors.lastname: Grus
authors.forename: Jianzhi
authors.initials: J
authors.lastname: Zhang
mesh_terms: D000818:Animals; D005075:Biological Evolution; D015415:Biomarkers; D006801:Humans; D000069497:Origin of Life; D015398:Signal Transduction; D014714:Vertebrates / Q000235:genetics* / Q000378:metabolism; D019147:Vomeronasal Organ / Q000378:metabolism*
chemical_list: D015415:Biomarkers