Genetic Variation of Guide Dogs: Exploring Insertion Dynamics of Transposable Elements Associated with Hypersociability

Abstract

A recent study by Bridget vonHoldt (2107) identified a region in domesticated canines that parallels Williams-Beuren Syndrome in humans and underlies the hyper-sociability of domesticated dogs. Differences or patterns within these genes- WBSCR17, GTF2I and GTF2IRD1- have not explicitly been made between service dogs and general domesticated canines yet. The aim of this study is to genotype the polymorphic insertions of WBS-associated transposable elements (TEs) in 144 guide dogs and 300 non-guide dogs for comparison. Guide dogs are unique in that they play an extremely valuable role in the lives of the people who need them by granting both confidence and independence (Weiss, 2002). They are desired to have a very specific set of behavioral traits to perform the function well, including low levels of reactivity, hyperactivity, and distraction (Bray, et al, 2017). These behavioral traits suggest a lower level of sociability, so this experiment compared the number of TE insertions present in guide dogs to other dogs in the data set to see if there could be any kind of genetic predisposition. Through comparison of the allele frequency, genotype frequency, median insertion values at each locus, as well as regressional analysis that took into account breed and gender, it was found that two loci, Cfa6.6 and Cfa6.66, may be uniquely specific and therefore desirable for guide dogs. However, the strong likelihood of breed bias limits the ability of this study to conclusively identify unique regions.