Digging up the canine genome--a tale to wag about

There is incredible morphological and behavioral diversity among the hundreds of breeds of the domestic dog, CANIS FAMILIARIS. Many of these breeds have come into existence within the last few hundred years. While there are obvious phenotypic differences among breeds, there is marked interbreed genetic homogeneity. Thus, study of canine genetics and genomics is of importance to comparative genomics, evolutionary biology and study of human hereditary diseases. The most recent version of the map of the canine genome is comprised of 3,270 markers mapped to 3,021 unique positions with an average intermarker distance of approximately 1 Mb. The markers include approximately 1,600 microsatellite markers, about 1,000 gene-based markers, and almost 700 bacterial artificial chromosome-end markers. Importantly, integration of radiation hybrid and linkage maps has greatly enhanced the utility of the map. Additionally, mapping the genome has led directly to characterization of microsatellite markers ideal for whole genome linkage scans. Thus, workers are now able to exploit the canine genome for a wide variety of genetic studies. Finally, the decision to sequence the canine genome highlights the dog's evolutionary and physiologic position between the mouse and human and its importance as a model for study of mammalian genetics and human hereditary diseases.