Anchoring of canine linkage groups with chromosome-specific markers

A high-resolution genetic map with polymorphic markers spaced frequently th roughout the genome is a key resource for identifying genes that control sp ecific traits or diseases. The lack of rigorous selection against genetic d isorders has resulted in many breeds of dog suffering from a very high freq uency of genetic diseases, which tend to be breed-specific and usually inhe rited as autosomal recessive or apparently complex genetic traits. Many of these, closely resemble human genetic disorders in their clinical and patho logic features and are likely to be caused by mutations in homologous genes . To identify loci important in canine disease genes, as well as traits. as sociated with morphological and behavioral variation, we are developing a g enetic map of the canine genome. Here we report on an updated version of th e canine linkage map, which includes 341 mapped markers distributed over th e X and 37 autosomal linkage groups. The average distance between markers o n the map is 9.0 cM, and the linkage groups provide estimated coverage of o ver 95% of the genome. Fourteen linkage groups contain either gene-associat ed or anonymous markers localized to cosmids that have been assigned to spe cific canine chromosomes by FISH. These 14 linkage groups contain 150 micro satellite markers and allow us to assign 40% of the linkage groups to speci fic canine chromosomes. This new version of the map is of sufficient densit y and characterization to initiate mapping of traits of interest.