August 26, 2016

Dog Aggression Toward Owner Can Be Due to Genetic Predisposition

Researchers at the Nationwide Children’s Hospital have found that dogs have a genetic predisposition to aggression directed towards an owner or a familiar dog; this fear and aggression is not the same as when those feelings are directed toward unfamiliar dogs and humans.
By Kristi Rosa
Everyone experiences some type of anxiety on occasion, but for the most part, it’s fleeting; the feeling comes and goes. For others, the feeling does not go away, instead, it worsens as time goes by: this is an anxiety disorder. According to a Nationwide Children’s Hospital press release, in the United States, anxiety disorders are the most common kind of mental illness. Although much research has been done in the realm of anxiety’s biochemistry, much remains unknown about the role that genetic may play.

Researchers at the Nationwide Children’s Hospital report in a study that was recently published in BMC Genomics, that “man’s best friend” has a genetic predisposition to aggression directed towards an owner or a familiar dog. Additionally, this fear and aggression is not the same as when those feelings are directed toward unfamiliar dogs and humans. Twelve genes are associated with these traits, according to the press release.

Carlos Alvarez, PhD, principal investigator in the Center for Molecular and Human Genetics in The Research Institute at Nationwide Children’s Hospital, said “Our strongest focus is on specific genes related to aggression toward unfamiliar humans and dogs, which are associated with highly relevant genes at two genome regions. Those genes are consistent with the core fear and aggression neural pathway known as the amygdala to hypothalamic-pituitary-adrenal-axis.”

The study conducted by Alvarez and his team aimed to better understand fear and aggression. The team was able to map behavioral traits by using breed stereotypes in order to conduct a series of interbreed genome scans. In order to ensure the validity of their findings, the researchers conducted their study in two phases: discovery and validation. In the first phase, the researchers used nine behavioral phenotypes for fear and aggression to analyze two SNP datasets, according to the study. Then, the researchers set out to validate their findings by predicting behavior for breeds that were not included in the study’s first phase. The researchers hypothesized that they would be able to predict certain behavioral traits based on a few markers.

The discovery data that the team of researchers used was what they refer to as “C-BARQ phenotypes” which are behavioral phenotypes that include “values and distributions for aggression and fear variables” that had previously been published for the 30 “most popular breeds” of the American Kennel Club. The data consisted of a collection of behavior information of dogs that were registered with the American Kennel Club that had been reported by the owners; 6,818 animal subjects were used to compose this set of data.

According to the study, “C-BARQ data decomposes aggression into 4 classes: stranger-directed aggression (towards unfamiliar humans), dog-directed aggression (toward unfamiliar dogs), owner-directed aggression and dog rivalry (towards familiar humans and dogs respectively). In a similar way C-BARQ decomposes fear into 5 classes: stranger-oriented fear (towards unfamiliar humans), dog-oriented fear (towards unfamiliar dogs), nonsocial fear (towards environmental phenomena), separation-related anxiety (being left alone by the owner) and touch sensitivity.” Dog rivalry and touch sensitivity was previously validated using 200 dog subjects that had previously been diagnosed with behavior problems.

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