When the veterinarian encounters a disorder with an unknown etiology, the following criteria can identify the potential contribution of the animals genome to the problem: 1. The disorder occurs with higher frequency in a group of related animals than in the general population. 2. A defect involves the same anatomic site in a group of related animals. 3. The disease has a consistent age of onset and clinical course. 4. The disease increases in frequency with inbreeding. 5. The disorder is consistently associated with a specific chromosomal anomaly. 6. The disorder can be traced to an abnormality in a single specific protein molecule. Veterinarians must access the information that knowledgeable breeders gather and channel that information constructively into diagnostic tests, test breedings, and data banks to work toward a common goal--discovery of the genetic basis of disease and development of appropriate breeding programs to minimize or eliminate debilitating genetic problems in dogs.