A tobiano horse that is homozygous will ALWAYS throw a spotted coat pattern or a tobiano coat pattern in their offspring. Even if the other parent has a solid, overo, or tobiano coat pattern, the homozygous tobiano gene will be dominant in the offspring's coat color. The tobiano gene is an inherited dominant gene.
To determine if a horse is homozygous, you must evaluate the following:
1. Pedigree: Both parents must be tobiano.
2. Phenotype: The horse should have secondary body spotting such as "ink spots" or "paw print".
3. Test Breeding: The horse should have no solid offspring from solid mates.
4. Studbook Data: The horse has no solid offspring.
5. Genetic Marker Analysis: Genetic testing by approved laboratory.
