Do dogs display behavioral traits central to Williams-Beuren Syndrome? Transposons, behavior & training success in assistance dogs

Abstract Williams-Beuren Syndrome (WBS) is a neurodevelopmental disorder in humans caused by a hemizygous deletion of 28–30 genes and characterized by hypersociability and cognitive deficits. In canines, the homologous chromosomal region shows a strong signature of selection in domestic dogs relative to gray wolves, and four structural variants derived from transposons have been associated with social behavior. To explore these genetic associations in more phenotypic detail—as well as their role in training success—we genotyped 1,001 assistance dogs from Canine Companions for Independence®, including both successful graduates and those released from the training program for behavioral problems. We collected phenotypes on each dog using puppy-raiser questionnaires, trainer questionnaires, and both cognitive and behavioral tests. Using Bayesian mixed models, we found strong associations between genotypes and certain behavioral measures, including separation-related problems, aggression when challenged or corrected, and reactivity to other dogs. Furthermore, we found moderate differences in the genotypes of dogs who graduated versus those who did not; insertions in GTF2I showed the strongest association ( β = 0 . 23, CI 95% = -0.04, 0.49), translating to an odds-ratio of 1.25 for one insertion. Our results provide insight into the role of each of these loci in canine sociability and may inform breeding and training practices for working dog organizations. Furthermore, the observed importance of GTF2I supports the emerging consensus that GTF2I genotypes, dosage, and expression are particularly important for the social behavior phenotypes seen in WBS.