Inheritance: incomplete autosomal-dominant
→ Incomplete means that horses with only one copy of the variant (T/n) will show a less pronounced phenotype than horses with two copies of the variant (T/T).
- Big white patches with distinct edges.
- Usually have a colored head and white patches often reach over back.
- Tobiano pattern may obscure Frame Overo or other patterns.
- Horses with two copies of the variant (T/T) usually have an increased amount of white.
- Although rare, mostly/completely solid horses can be positive for Tobiano. They may be called “cryptic” or “hidden” Tobianos.
- Tobiano is found in many different breeds.
|n/n||No Tobiano mutation.|
|T/n||The horse has one copy of the T-variant → pattern with distinct edges and big patches. Commonly colored head (maybe with white markings).
|T/T||The horse has two copies of the T-variant → pattern with distinct edges, big patches. Very similar to heterozygous (T/n) individuals.|
Test information: This test detects a chromosomal inversion near the KIT gene.
Brooks, S.A., Lear, T.L., Adelson, D.L., Bailey, E.: A chromosome inversion near the KIT gene and the Tobiano spotting pattern in horses. Cytogenet Genome Res.,119(3-4):225-30, 2007. Doi: 10.1159/000112065.
Further information is available at Online Mendelian Inheritance in Animals.