Impact of Domestication and Artificial Selection on the Genetic Architecture of Canine Phenotypic Diversity

As the first domesticated species, dogs have diversified tremendously compared to their gray wolf progenitors. Extreme differences in morphology, behavior and genetic disease risk are well documented among modern dog breeds, and can be exploited by geneticists to determine the underlying genetic architecture of these traits. Much of this diversification arose from modern breeding practices, including strong artificial selection and closed breeding populations with relatively low effective population sizes. However, most dogs have not been selectively bred and live as free-ranging or free-breeding village dogs throughout the world. Using dense genotyping of a diverse sample of village and purebred dogs from across the world, we can compare the highly modified genetic architecture of morphological diversity among purebred dogs to that observed in the village dogs. Although we observe a simple genetic architecture in village dogs mimicking that of purebred dogs for some traits, we also find evidence of relaxation of selective constraint and adaptation to local environment for others. The ability efficiently find variants underlying phenotyping diversity in purebred dogs coupled with genetic investigation of these variants in natural populations offers a unique system for understanding the genetics of domestication and rapid adaptation.