Polymorphism of olfactory and neurotransmitters receptor genes in drug and explosives detection dogs can be associated with differences in detection performance

Abstract

The aim of this study was to identify candidate genes that could be useful predictors of better detection performance in drugs and explosives detection dogs. Single nucleotide polymorphisms in selected canine olfactory receptor genes responsible for olfactory acuity (OR1P2-like, OR51H5-like, OR52N9-like,OR52P3-like, OR9S13-like), and genes related to the serotoninergic (SLC6A4-like, HTR1A, HTR2B-like) and dopaminergic (SLC6A3-like, DRD1-like, DRD2-like) neurotransmission with a documented role in operant conditioning, were analysed. From a total of 91 certified drug and 57 explosives detection dogs, 10 individuals demonstrating the best and 10 with the poorest detection performance, as evaluated by detection speed and style of searching, were chosen for genetic studies. In this work for the first time we show that not only polymorphisms in selected canine olfactory receptor genes, but also polymorphisms in genes encoding the transporter protein for dopamine uptake or the 5-HT2B receptor, are important for canine olfactory detection. The G allele at the OR52N9-like:c.176 A > G and OR52N9-like:c.288 T > G loci had a negative, whereas the A allele at the OR9S13-like:c.592 G > A locus had a positive, effect on the dogs' detection performance measured as mean search time and mean search style. Additionally, the presence of the C allele in the SLC6A3-like:c.181 G > C locus and the A allele in HTR2B-like:c.596 G > A locus was associated with reduced detection performance. We suggest that good candidate dogs for detection training could be chosen for military and civilian service based on favourable genotypes in the olfactory and monoamine neurotransmitter receptor genes. This, however, should be investigated further in studies, particularly using dogs with the alleles of the candidate genes we have identified as correlated with increased performance.