Saddle Tan (As Locus)

General Information: The As Locus (AS), influenced by the RALY gene, plays a crucial role in the expression of the saddle tan pattern in certain dog breeds. This coat color pattern is characterized by an expansion of the tan markings typically found on the muzzle, above the eyes, and beneath the body in the black-and-tan coloration, where the tan extends further, often reducing the black to a patch on the back. Dogs with the saddle tan pattern usually are born black-and-tan, with the black areas receding as the dog matures. The pattern's expression is dependent on the interaction with other genetic loci, such as the E-locus, K-locus, and A-locus. Saddle tan is observed in a select group of breeds, including some terriers, scent hounds, and herding dogs, and is less about the presence of a specific gene and more about the combination and interaction of several genetic factors.

Gene / Testing Information: Genetic testing for the As Locus (AS), specifically examining the RALY gene, can identify the genetic status associated with the saddle tan coat color in dogs. The presence of the WT allele in the RALY gene leads to the saddle tan phenotype, which is dominant, but dogs must also have the appropriate genetic configuration at the E-locus, K-locus, and A-locus to express this trait. Testing can reveal whether dogs carry the dominant WT allele associated with saddle tan or the recessive dup allele associated with the standard black-and-tan pattern. For breeding practices, it is essential to understand the inheritance of these alleles to predict the coat color outcomes of potential litters. Breeders can use this genetic information to make informed decisions and manage expectations regarding the coat colors of their dogs, ensuring adherence to breed standards where applicable. The genetic test provides clarity and assists in maintaining the desired aesthetic traits within the breed lines.