Behavioral genetic study on canine temperament

本研究旨在揭示犬性情的遗传背景。我们首先在美国的“导盲犬”机构收集候选导盲犬的血液样本和行为分数。训练师在判断导盲犬的适宜性时，认为攻击性比焦虑更重要。然后，我们对一些目标基因（神经递质相关基因）进行测序，以寻找这些基因的遗传多态性。我们在已鉴定基因的编码区域发现了几个缺失的snp，如单胺氧化酶亚型A （MAOA）和B (MAOB)，血清素转运蛋白，5-羟雷丁胺受体（5-HTR） 1B， 2A和2C。为了分析这些多态性的品种差异，我们采集了血液样本，并通过兽医从业人员对饲主进行了问卷调查。7个代表性品种间鉴定出的多态性均存在品种差异。通过问卷调查和遗传分析相结合，我们发现多巴胺D4受体基因多态性与“在陌生地方对主人的过度依恋”、5HTR1B基因多态性与“攻击性”之间的关系。这些发现可能表明，神经递质相关基因的多态性与狗的一些行为特征有关，这可能是造成品种间和品种内行为倾向差异的原因。

This study was conducted to reveal the genetic background of canine temperament. We first collected blood samples and behavioral scores of candidate guide dogs at the "Guide Dogs for the Blind" institution in USA. The trainers regarded aggression more important than anxiety when they judged the suitability as the guide dog. We then sequenced some target genes (neurotransmitter-associated genes) to search for genetic polymorphisms of these genes. We found several missence SNPs at the coding regions of identified genes, such as monoamine oxidase subtypes A (MAOA) and B (MAOB), serotonin transporter, 5-hydroxytriptamine receptor (5-HTR) 1B, 2A, and 2C. To analyze the breed differences of these polymorphisms, we collected blood samples and carried out a questionnaire survey to owners via veterinary practitioners. There were breed differences in all the identified polymorphisms among 7 representative breeds. By the combining the questionnaire survey and the genetic analysis, we found the relationships between the polymorphism of dopamine D4 receptor gene and "over-attachment to the owner in an unfamiliar place", that of 5HTR1B gene and "aggression". These findings may suggest that polymorphisms of neurotransmitter-associated genes are related to some of the behavioral traits in dogs, which may be responsible for inter-breeds as well as intra-breed differences of behavior predisposition.