Genetic testing of dogs predicts problem behaviors in clinical and nonclinical samples

Abstract

Very little is known about the etiology of personality and psychiatric disorders. Because the core neurobiology of many such traits is evolutionarily conserved, dogs present a powerful model. We previously reported genome scans of breed averages of ten traits related to fear, anxiety, aggression and social behavior in multiple cohorts of pedigree dogs. As a second phase of that discovery, here we tested the ability of markers at 13 of those loci to predict canine behavior in a community sample of 397 pedigree and mixed-breed dogs with individual-level genotype and phenotype data. We found support for all markers and loci. By including 122 dogs with veterinary behavioral diagnoses in our cohort, we were able to identify eight loci associated with those diagnoses. Logistic regression models showed subsets of those loci could predict behavioral diagnoses. We corroborated our previous findings that small body size is associated with many problem behaviors and large body size is associated with increased trainability. Children in the home were associated with anxiety traits; illness and other animals in the home with coprophagia; working-dog status with increased energy and separation-related problems; and competitive dogs with increased aggression directed at familiar dogs, but reduced fear directed at humans and unfamiliar dogs. Compared to other dogs, Pit Bull-type dogs were not defined by a set of our markers and were not more aggressive; but they were strongly associated with pulling on the leash. Using severity-threshold models, Pit Bull-type dogs showed reduced risk of owner-directed aggression (75th quantile) and increased risk of dog-directed fear (95th quantile). Our findings have broad utility, including for clinical and breeding purposes, but we caution that thorough understanding is necessary for their interpretation and use.

Genome scans of dog behavior implicate a gene network underlying psychopathology in mammals, including humans

“…In the Supplementary Text, we discuss the strengths and weaknesses of canine interbreed genome scanning. The findings are supported by our unpublished study of pedigree and mixed breed dogs with individual-level genotype and C-BARQ phenotype data 18 . Further support comes from the geneset overlap between the combined interbreed C-BARQ studies and gene-based canine cognition GWASs using individual-level genotype and cognitive testing data 17 (hypergeometric P=2.13x10 -18 ).…”

“…Ten additional loci were supported by another interbreed GWAS 6 . That quasi-replication mitigates possible type I error (see Discussion for support from studies with individual-level phenotypes and genotypes 17,18 ). The geneset analyses below suggest it is unlikely our mapping has a high false positive rate.…”

Aggressive behaviour is affected by demographic, environmental and behavioural factors in purebred dogs

“…In addition, we speculate that, as people may not feel threatened by small dogs, they might not consider behaviour important when making breeding decisions. Further, a recently published study associated several problematic behaviours with genetic variants known to cause small body size 41 .…”

Genome scanning of behavioral selection in a canine olfactory detection breeding cohort

“…Because Labrador Retrievers are very popular working dogs, an important finding is that behavioral haplotypes previously mapped or shown to be under selection in this breed 12 , 27 were not associated with pretraining elimination due to behavior. That was also true for large effect behavioral variation mapped in interbreed GWASs 13 , 14 , 35 , 36 . For instance, a haplotype with a coding variant of IGSF1 that is strongly associated with anxiety and fear traits across breeds and has an allele frequency of 0.18 in pet Labradors 14 was homozygous non-risk in the present cohort.…”