In the last five years, canine genetics has gone from map construction to complex disease deconstruction. The availability of a draft canine genome sequence, dense marker chips, and an understanding of the genome architecture has changed the types of studies canine geneticists can undertake. There is now a clear recognition that the dog system offers the opportunity to understand the genetics of both simple and complex traits, including those associated with morphology, disease susceptibility, and behavior. In this review, we summarize recent findings regarding canine domestication and review new information on the organization of the canine genome. We discuss studies aimed at finding genes controlling morphological phenotypes and provide examples of the way such paradigms may be applied to studies of behavior. We also discuss the many ways in which the dog has illuminated our understanding of human disease and conclude with a discussion on where the field is likely headed in the next five years.

In recent years Canis familiaris, the domestic dog, has drawn considerable attention as a system in which to investigate the genetics of disease susceptibility, morphology and behavior. Because dogs show remarkable intrabreed homogeneity, coupled with striking interbreed heterogeneity, the dog offers unique opportunities to understand the genetic underpinnings of natural variation in mammals, a portion of which is disease susceptibility. In this review, we highlight the unique features of the dog, such as population diversity and breed structure, that make it particularly amenable to genetic studies. We highlight recent advances in understanding the architecture of the dog genome, which propel the system to the forefront of consideration when selecting a system for disease gene studies. The most notable benefit of using the dog for genetic studies is that dogs get many of the same diseases as humans, with a similar frequency, and the same genetic factors are often involved. We discuss two approaches for localizing disease genes in the dog and provide examples of ongoing studies.