Abstract
BACKGROUND: Trainability in dogs is affected by learning aptitude and memory capacity. While this trait has a heritable basis in canines, the specific genetic loci responsible for it remain unknown. Our previous results suggested that the BDNF, CCK and TAC1 genes are associated with learning and memory in canines. Experimental validation is crucial to confirm the effects of these candidate genes on trainability. Understanding the genetic foundation of this trait would offer insight into the inheritance pattern of complex behavioural characteristics. OBJECTIVE: This study aimed to assess the genetic variations within candidate genes and explore their potential associations with behavioural phenotypes in dogs. METHODS: The behavioural characteristics of 123 male Belgian Malinois dogs were assessed using a customised questionnaire. Target regions of candidate genes were screened for genetic variation by single-strand conformational polymorphism (SSCP). Following that, SSCP banding patterns were sequenced, and putative transcription factor binding sites were predicted using bioinformatics tools. Quantitative association analysis between identified genetic variants and behavioural trait scores was performed using the general linear model (GLM). RESULTS: Sequencing the coding and flanking regions revealed three mutations (c.-89C>T, c.-162G>C and c.*33T>A) in the dog TAC1 gene. Bioinformatics analysis predicted two single nucleotide polymorphisms (SNPs) were located within the putative TAC1 promoter and could disrupt transcription factor binding sites. Statistical tests revealed that the c.-89C>T was significantly associated with excitability (p < 0.01), while the c.-162G>C was significantly associated with trainability level (p < 0.05). CONCLUSION: In summary, we identified two regulatory SNPs in the 5'-UTR promoter region of the TAC1 gene that are associated with excitability and trainability in Belgian Malinois dogs. These genetic variations have the potential to alter the binding sites of transcription factors NRF1 and OTX1, consequently influencing TAC1 expression and related behavioural characteristics. Our findings implicate TAC1 polymorphisms as candidates influencing breed-specific behavioural characteristics in canines. Further studies on diverse breeds of dogs are necessary to validate these SNPs' effects.