While cats have been living with humans for nearly 10,000 years, selection for specific traits has only recently occurred. While many of these traits are innocuous, others occasionally have associated deleterious phenotypes. These include deafness in dominant white cats, lameness in Manx and Cymrics, and joint problems in Scottish Folds. These are all dominant traits and, in the case of Manx, Cymrics, and Scottish Folds, manifestation of the disease occurs when both maternal and paternal genes are affected. The genes and associated mutations that result in these phenotypes have yet to be identified. Similarly, the genetic mutation for dominant white and the allele for deafness have yet to be determined. This proposal will obtain sample sets sufficient for determining the causative genes for both dominant white/deafness and taillessness. Deaf cats will be determined via hearing tests by qualified veterinarians and small pedigrees, sufficient for candidate gene exclusion, will be established. Using available genetic resources, the samples collected will be used for case control studies to identify candidate genes.