title: DRD4 and TH gene polymorphisms are associated with activity, impulsivity and inattention in Siberian Husky dogs.
abstract: Both dopamine receptor D4 (DRD4) exon 3 and tyrosine hydroxylase (TH) intron 4 repeat polymorphisms have been linked to activity and impulsivity in German Shepherd dogs (GSDs). However, the results in GSDs may not be generalisable to other breeds, as allelic frequencies vary markedly among breeds. We selected the Siberian Husky for further study, because it is highly divergent from most dog breeds, including the GSD. The study sample consisted of 145 racing Siberian Huskies from Europe and North America. We found that this breed possesses seven DRD4 length variants, two to five more variants than found in other breeds. Among them was the longest known allele, previously described only in wolves. Short alleles of the DRD4 and TH repeat polymorphisms were associated with higher levels of activity, impulsivity and inattention. Siberian Huskies possessing at least one short allele of the DRD4 polymorphism displayed greater activity in a behavioural test battery than did those with two long alleles. However, the behavioural test was brief and may not have registered variation in behaviour across time and situations. Owners also completed the Dog-Attention Deficit Hyperactivity Disorder Rating Scale (Dog-ADHD RS), a more general measure of activity and attention. Siberian Huskies from Europe with two short alleles of the TH polymorphism received higher ratings of inattention on the Dog-ADHD RS than did those with the long allele. Investigation of the joint effect of DRD4 and TH showed that dogs possessing long alleles at both sites were scored as less active-impulsive than were others. Our results are aligned with previous studies showing that DRD4 and TH polymorphisms are associated with activity-impulsivity related traits in dogs. However, the prevalence of variants of these genes differs across breeds, and the functional role of specific variants is unclear.
authors.affiliation: Department of Psychology, Columbia University, 1190 Amsterdam Ave., New York, NY, 10027, USA.
authors.forename: Michele
authors.initials: M
authors.lastname: Wan
authors.forename: Krisztina
authors.initials: K
authors.lastname: Hejjas
authors.forename: Zsolt
authors.initials: Z
authors.lastname: Ronai
authors.forename: Zsuzsanna
authors.initials: Z
authors.lastname: Elek
authors.forename: Maria
authors.initials: M
authors.lastname: Sasvari-Szekely
authors.forename: Frances A
authors.initials: FA
authors.lastname: Champagne
authors.forename: Adám
authors.initials: A
authors.lastname: Miklósi
authors.forename: Enikő
authors.initials: E
authors.lastname: Kubinyi
mesh_terms: D000818:Animals; D001288:Attention; D017931:DNA Primers / Q000235:genetics; D004283:Dog Diseases / Q000235:genetics*; D004285:Dogs; D005260:Female; D005787:Gene Frequency / Q000235:genetics; D005838:Genotype; D006801:Humans; D007175:Impulsive Behavior / Q000235:genetics*; D008297:Male; D001523:Mental Disorders / Q000235:genetics / Q000662:veterinary*; D009043:Motor Activity / Q000235:genetics*; D011110:Polymorphism, Genetic / Q000235:genetics; D025341:Principal Component Analysis; D050638:Receptors, Dopamine D4 / Q000235:genetics*; D011795:Surveys and Questionnaires; D014446:Tyrosine 3-Monooxygenase / Q000235:genetics*
chemical_list: D017931:DNA Primers; D050638:Receptors, Dopamine D4; D014446:Tyrosine 3-Monooxygenase
keywords: VNTR polymorphism; behaviour; canine; dopamine receptor D4; genetic association; sled dogs; tyrosine hydroxylase