Study Maps Genes Causing Fear and Aggression in Dogs .

Scientists believe they may have found a genetic trigger for aggression in dogs. The new findings could have applications for both animals and humans. It is common to see dogs with anxiety or aggression issues in veterinary practice. These traits can severely impact quality of life for both the canine and their human owners by influencing the dog’s health and social interactions. In an attempt to better understand these traits, researchers at Nationwide Children’s Hospital worked to identify genetic components, separate from physiology and neuroanatomy, that lead to the development of such traits. In the study, scientists conducted genomewide association (GWA) mapping of breed stereotypes for fear and aggression traits among several hundred dogs. The dogs represented a variety of breeds. The findings were confirmed using GWA in a second test group composed of overlapping breeds of dogs. A previously identified locus – the specific location of a gene’s DNA sequence on a chromosome - was used to create a model predicting fear and aggression stereotypes in a third, final test group of dogs that were not involved in the first two studies. The results of the study showed that four genome loci on two different chromosomes were involved in the development of these traits. Two loci variants, IGF1 and HMGA2, in dogs of small body size were shown to be associated with separation anxiety, touch-sensitivity, owner directed aggression, and dog rivalry. The two other loci, GNAT3 and CD36 were not associated with body size. These two loci were shown to be associated with touch-sensitivity, non-social fear, and fear and aggression directed toward unfamiliar dogs and humans. source