The T-locus hold several different genetic variants, which are responsible for the appearance of pigmented spots in the unpigmented areas of piebald dogs (through the S-locus) and the expression of these spots as either ticking, dots, roan or mottle. Recent studies found the genetic variant that causes those spots with the dominant Tr-allele. The Tr-allele is dominant to the wildtype allele (N or t) and is the basis for all forms of spots. Therefore, the occurrence of this characteristic can be found with the genetic test for the Tr-allele, while the exact expression cannot be distinguished by this test.
1-2 weeks after arrival of the sample in the lab