Genomics of Canine Detection - Smell Starts Here
Trained dogs are one of the most common, sensitive and versatile means for detecting concealed contraband, such as explosives. What makes a particular dog or breed good or bad at sensing odorant molecules has remained a mystery. The first step is understanding the genetic diversity of the canine olfactory receptors. These olfactory receptors (ORs), which interact with odorant molecules, form the largest known gene superfamily in most mammals. These are expressed on the surface of the cilia of the olfactory sensory neuron lining the nasal cavity. Researchers at the University of Rennes in France have begun to understand this and to answer the crucial questions: Are there any means of identifying animals with olfactory receptors before beginning costly training programs? Do some breeds have better overall sensing abilities? Can breeding further enhance the sensing capabilities of dogs? Can we offer breeders suitable genetic tests? Building on the National Institutes of Health Dog Genome Project sequence, the researchers in France conducted a comprehensive analysis of the canine olfactory receptor repertoire. They assessed canine breed olfactory genetic diversity, developed a preliminary list of OR genes that are essential for the recognition of explosives and laid the basis for the development of a genetic test that is based on a selected subset of OR genes. The diagram shows an olfactory receptor protein with the positions of 55 single nucleotide polymorphisms from http://jhered.oxfordjournals.org/cgi/reprint/96/7/812.