Canine olfactory are well adapted for detecting a vast number of odorous substances varying in shape and size. Odour discrimination is made possible when odorants activate olfactory receptors (OR) on the olfactory neuron for further signal transduction to the brain.
A study was carried out to derive the link between polymorphism exhibited by the transmembrane domain loops of the G-protein coupled OR, and accuracy of odour discrimination protein in sniffer dogs. There were three main findings from the study. Firstly, it was discovered that a Guanine to Adenine transition at Position 592 in the cOR9S13 Gene had substituted alanine to threonine at position 198 in the EC2 receptor structure. This improved the receptor-binding affinity of some odorous molecules, improving scent detection skills of the dogs. Secondly, hypothetical polymorphic sites in 2 OR genes were expected to play a role in the effectiveness of odour discrimination. Thirdly, polymorphisms which showed significant influence on the dogs’ detecting abilities were not located in the binding pocket of chosen OR. This suggests that an alteration in other parts of the receptor structure may alter odour detection ability.
It was concluded that the influence of polymorphic sites in detecting different substance will require further study as the performance of sniffer dogs can also be explained by other environmental, behavioural, and genetic factors.
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Links
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References
Lesniak, A., Walczak,M., Jezierski,T., Sacharczuk,M., Gawkowski,M., & Jaszczak,K, (2008) ‘Canine Olfactory Receptor Gene Polymorphism and its Relation to Odour Detection Performance by Sniffer Dogs’, Journal of Heredity, 99(5), 518-527
