The dog and rat olfactory receptor repertoires

Pascale Quignon¹^,4 , Mathieu Giraud² , Maud Rimbault¹ , Patricia Lavigne¹ , Sandrine Tacher¹ , Emmanuelle Morin² , Elodie Retout² , Anne-Sophie Valin² , Kerstin Lindblad-Toh³ , Jacques Nicolas² and Francis Galibert¹

¹UMR 6061, Génétique et Développement CNRS-Université de Rennes 1, 35043 Rennes Cedex, France

²IRISA, campus de Beaulieu, 35042 Rennes Cedex, France

³Broad Institute of MIT and Harvard, Charles Street, Cambridge, MA 02141, USA

⁴NIH/NHGRI/50 South Drive, MSC 8000, Bethesda, MD 20892-8000, USA

author email corresponding author email

Genome Biology 2005, 6:R83doi:10.1186/gb-2005-6-10-r83


Published:	28 September 2005

Subject areas: Neurobiology, Genome studies, Evolution

Abstract

Background

Dogs and rats have a highly developed capability to detect and identify odorant molecules, even at minute concentrations. Previous analyses have shown that the olfactory receptors (ORs) that specifically bind odorant molecules are encoded by the largest gene family sequenced in mammals so far.

Results

We identified five amino acid patterns characteristic of ORs in the recently sequenced boxer dog and brown Norway rat genomes. Using these patterns, we retrieved 1,094 dog genes and 1,493 rat genes from these shotgun sequences. The retrieved sequences constitute the olfactory receptor repertoires of these two animals. Subsets of 20.3% (for the dog) and 19.5% (for the rat) of these genes were annotated as pseudogenes as they had one or several mutations interrupting their open reading frames. We performed phylogenetic studies and organized these two repertoires into classes, families and subfamilies.

Conclusion

We have established a complete or almost complete list of OR genes in the dog and the rat and have compared the sequences of these genes within and between the two species. Our results provide insight into the evolutionary development of these genes and the local amplifications that have led to the specific amplification of many subfamilies. We have also compared the human and rat ORs with the human and mouse OR repertoires.