Genetics of domesticated behavior in dogs and foxes

Differences in the behavior of the domestic dog (Canis lupus familiaris) and its progenitor species, the gray wolf (Canis lupus), are well recognized but the mechanisms of the wolf to dog transformation remain an area of scientific debate. A view of dog domestication that is centered on genetic selection for behavioral traits receives support from the famous Russian farm-fox experiment that began in the 1950s. Selection of foxes (Vulpes vulpes), separately, for tame and for aggressive behavior, has yielded two strains with markedly different, genetically determined, behavioral phenotypes. Tame-strain foxes communicate with humans in a positive manner and are eager to establish human contact. Conversely, foxes from the aggressive strain are aggressive to humans and difficult to handle. Although selected solely for behavior, changes in physiology, morphology, and appearance with significant parallels to characteristics of the domestic dog were observed in the selected strains. The genetic analysis of the fox populations identified several genomic regions that are homologous to the regions in the dog genome that differentiate dogs from wolves. Although the genetic regulation of domesticated behavior is far from being completely understood enormous progress has been made in this field. This chapter reviews studies of behavior and genetics in dogs and foxes and highlights the role of selection for behavior in ancient and modern dog formation.