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| Dogs and Separation Anxiety |
Karen L. Overall, MA, VMD, PhD, Steven P. Hamilton, MD, PhD, Melanie Lee Chang, PhDUnderstanding the genetic basis of canine anxiety: phenotyping dogs for behavioral, neurochemical, and genetic assessmentJournal of Veterinary Behavior: Clinical Applications and Research, Volume 1, Issue 3, November–December 2006, Pages 124–141
Introduction: the Canine Behavioral Genetics Project (CBGP)
Behavioral
problems account for the death, relinquishment, or the end of breeding
careers of more dogs than does any other set of problems (
[Miller et al 1996],
[Patronek et al 1996],
[Salman et al 1998] and
[Salman et al 2000];
Scarlett et al., 1999;
[Shore et al 2003],
[Mondelli et al 2004] and
[Shore 2005]).
Whereas many behavioral complaints involve management-related issues or
dog-human temperament mismatches, the behavioral concerns that are most
interesting to scientists and breeders alike are those with familial
patterns.
A number of conditions
have been identified as running in family lines of a number of breeds
including, but not restricted to, generalized anxiety/fear, noise
phobia, impulse/control aggression, conspecific aggression, predatory
aggression, and obsessive-compulsive disorder (
[Overall 1994],
[Overall and Dunham 2002] and
[Overall 2005]).
Most of these conditions appear sometime between one and two years of
age, the social maturity period, during which neural systems are
undergoing extensive developmental changes. The potential benefit of
genetic counseling is clear, and the potential to make dogs “safer” and
happier is substantial. Understanding the genetic bases of behavioral
problems will lead to more humane treatment of dogs, fewer public health
risks, an improved public perception of dogs as pets, and a
considerable lessening in the recycled pet problem. Additionally,
elucidation of the biological systems underlying pathological behavior
will heighten our general understanding of the underlying molecular
biology of behavior, allowing the dog to contribute to this rapidly
evolving field.
Over 50 breeds
across all seven AKC groups have family lines in which
“fear/shyness/nervousness/panic/anxiety” is a major breeder-reported
concern (Overall, unpublished). Within these breeds, this “trait” often
follows familial lines, suggesting a heritable basis. This pattern has
been noted for many physical conditions in dogs (
[Sutter et al 2004] and
[Lark et al 2006]),
but little emphasis has been placed on behavioral conditions because of
the difficulty in defining a clear phenotype. Although recognition of
other genetically mediated conditions is often straightforward, based on
easily observable clinical phenomena that are defined by consensus
(e.g., cancer, retinopathies, narcolepsy), assignment of behavioral
phenotypes can be open to misclassification or misinterpretation (
[Overall 2005] and
[Overall and Burghardt 2006]).
The
broad goal of the CBGP is to explore the genetic background of
anxiety-related behavioral problems in dogs. To do so, we must: (1)
solicit the participation of owners of candidate dogs possibly affected
by anxiety-related behavioral problems; (2) identify affected and
unaffected dogs, using the necessary and specific diagnostic criteria to
make a diagnosis of the condition; (3) confirm the presence of the
relevant diagnosis in these dogs and if possible in their family lines,
using reliable, repeatable, and validated behavioral measures involving
questionnaires and videos; and (4) obtain DNA samples for genetic
linkage and association analyses, along with the relevant pedigrees. In
this article, we discuss the distinction between diagnosis and
phenotype, and we describe our protocol for assessing behavioral
phenotypes in dogs, addressing the second and third aspects of our
project just discussed.
