Evidence for the effect of serotonin receptor 1A gene (HTR1A) polymorphism on tractability in Thoroughbred horses |
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| Authors: | Y. Hori T. Tozaki Y. Nambo F. Sato M. Ishimaru M. Inoue‐Murayama K. Fujita |
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| Affiliation: | 1. Department of Psychology, Graduate School of Letters, Kyoto University, Kyoto, Japan;2. Japan Society for the Promotion of Science, Kojimachi Business Center Building, Chiyoda‐ku, Tokyo, Japan;3. Genetic Analysis Department, Laboratory of Racing Chemistry, Utsunomiya, Tochigi, Japan;4. Department of Clinical Veterinary Science, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido, Japan;5. Hidaka Training and Research Center, Japan Racing Association, Urakawa, Hokkaido, Japan;6. Wildlife Research Center, Kyoto University, Sakyo, Kyoto, Japan;7. Wildlife Genome Collaborative Research Group, National Institute for Environmental Studies, Tsukuba, Ibaraki, Japan |
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| Abstract: | Tractability, or how easily animals can be trained and controlled, is an important behavioural trait for the management and training of domestic animals, but its genetic basis remains unclear. Polymorphisms in the serotonin receptor 1A gene (HTR1A) have been associated with individual variability in anxiety‐related traits in several species. In this study, we examined the association between HTR1A polymorphisms and tractability in Thoroughbred horses. We assessed the tractability of 167 one‐year‐old horses reared at a training centre for racehorses using a questionnaire consisting of 17 items. A principal components analysis of answers contracted the data to five principal component (PC) scores. We genotyped two non‐synonymous single nucleotide polymorphisms (SNPs) in the horse HTR1A coding region. We found that one of the two SNPs, c.709G>A, which causes an amino acid change at the intracellular region of the receptor, was significantly associated with scores of four of five PCs in fillies (all Ps < 0.05) and one PC in colts (P < 0.01). Horses carrying an A allele at c.709G>A showed lower tractability. This result provides the first evidence that a polymorphism in a serotonin‐related gene may affect tractability in horses with the effect partially different depending on sex. |
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| Keywords: | behavioural trait genetic polymorphism neurotransmitter sexual difference single nucleotide polymorphism |
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