Sie befinden Sich nicht im Netzwerk der Universität Paderborn. Der Zugriff auf elektronische Ressourcen ist gegebenenfalls nur via VPN oder Shibboleth (DFN-AAI) möglich. mehr Informationen...
Deterioration of the G[alpha]o Vomeronasal Pathway in Sexually Dimorphic Mammals
Ist Teil von
PloS one, 2011-10, Vol.6 (10), p.e26436
Ort / Verlag
Public Library of Science
Erscheinungsjahr
2011
Link zum Volltext
Quelle
EZB Electronic Journals Library
Beschreibungen/Notizen
In mammals, social and sexual behaviours are largely mediated by the vomeronasal system (VNS). The accessory olfactory bulb (AOB) is the first synaptic locus of the VNS and ranges from very large in Caviomorph rodents, small in carnivores and ungulates, to its complete absence in apes, elephants, most bats and aquatic species. Two pathways have been described in the VNS of mammals. In mice, vomeronasal neurons expressing G[alpha]i2 protein project to the rostral portion of the AOB and respond mostly to small volatile molecules, whereas neurons expressing G[alpha]o project to the caudal AOB and respond mostly to large non-volatile molecules. However, the G[alpha]o-expressing pathway is absent in several species (horses, dogs, musk shrews, goats and marmosets) but no hypotheses have been proposed to date to explain the loss of that pathway. We noted that the species that lost the G[alpha]o pathway belong to Laurasiatheria and Primates lineages, both clades with ubiquitous sexual dimorphisms across species. To assess whether similar events of G[alpha]o pathway loss could have occurred convergently in dimorphic species we studied G-protein expression in the AOB of two species that independently evolved sexually dimorphic traits: the California ground squirrel Spermophilus beecheyi (Rodentia; Sciurognathi) and the cape hyrax Procavia capensis (Afrotheria; Hyracoidea). We found that both species show uniform expression of G[alpha]i2-protein throughout AOB glomeruli, while G[alpha]o expression is restricted to main olfactory glomeruli only. Our results suggest that the degeneration of the G[alpha]o-expressing vomeronasal pathway has occurred independently at least four times in Eutheria, possibly related to the emergence of sexual dimorphisms and the ability of detecting the gender of conspecifics at distance.