Differential gene expression in brain tissues of aggressive and non-aggressive dogs

This study describes differential expression of the UBE2V2 and ZNF227 genes in brains of aggressive and non-aggressive dogs. It also reports differential expression for eight of the studied genes across four different brain tissues (amygdala, frontal cortex, hypothalamus, and parietal cortex). Sex differences in transcription levels were detected for five of the nine studied genes.The study showed significant differences in gene expression between brain compartments for most of the investigated genes. Increased expression of two genes was associated with the aggression phenotype. Although the UBE2V2 and ZNF227 genes have no known function in regulation of aggressive behaviour, this study contributes to preliminary data of differential gene expression in the canine brain and provides new information to be further explored.The domestic dog (Canis familiaris), with its more than 400 recognised breeds [1], displays great variation in behaviour phenotypes. Favourable behaviour is important for well-being and negative traits such as aggression may ruin the owner-dog relationship and lead to relinquishment to shelters or even euthanasia of otherwise healthy dogs [2,3]. Behavioural traits result from an interaction of both genetic and environmental factors. Breed-specific behavioural traits such as hunting, herding and calmness/aggression are, however, evidence of a large genetic component and specific behaviours show high heritabilities [4-8].Traditionally, rodents have provided the most important models for studies of genes involved in human mental illness. With the whole-genome sequencing of the modern dog completed [9], a new, efficient model for genetic studies has emerged. The dog suffers from a number of behavioural disorders and many of these have human parallels that are treated with the same medicines [10-14]. Canine patients from breeds with an increased risk of aggression, anxiety, and stereotypic behaviours provide important resources for genetic research.Funct