Canine behavioral genetics: pointing out the phenotypes and herding up the genes

Abstract

An astonishing amount of behavioral variation is captured within the more than 350 breeds of dog recognized worldwide. Inherent in observations of dog behavior is the notion that much of what is observed is breed specific and will persist, even in the absence of training or motivation. Thus, herding, pointing, tracking, hunting, and so forth are likely to be controlled, at least in part, at the genetic level. Recent studies in canine genetics suggest that small numbers of genes control major morphologic phenotypes. By extension, we hypothesize that at least some canine behaviors will also be controlled by small numbers of genes that can be readily mapped. In this review, we describe our current understanding of a representative subset of canine behaviors, as well as approaches for phenotyping, genome-wide scans, and data analysis. Finally, we discuss the applicability of studies of canine behavior to human genetics.

Figure 1

Canine Variation Shown are examples of the cane corso and a Chihuahua mix (A). The cane corso is a large breed weighing, on average, 110 lbs (males) in contrast to the Chihuahua, one of the smallest, sometimes weighing under 3 lbs. Also shown are (B) the pug and (C) Afghan hound, which exhibit dramatic differences in head shape. Most dog breeds were developed in Europe within the last 300 years. The AKC recognizes nearly 157 breeds, although there are about 350 noted worldwide. Breeds differ in phenotype in terms of overall body size, coat color, length and texture, head shape, leg length, and dozens of other attributes.

Figure 2

Herding Behavior Dogs have been bred for a large number of behaviors including hunting, pointing, herding, guiding, etc. Shown is an example of the border collie herding livestock. Photo by Dan Weber.