What is the difference between a Homozygous Tobiano and a Heterozygous Tobiano?
A foal inherits one pattern gene from each parent. If the foal inherits the same gene from each parent, then the foal is said the be Homozygous for that pattern gene. If a foal inherits one pattern gene from the mare and a different pattern gene from the sire, then the foal has two different pattern genes, and is said to be Heterozygous. For example, if a Tobiano mare passes a Tobiano gene to her foal, and the foal’s sire is also Tobiano, and also passes on the gene, then the foal will be Homozygous Tobiano. This foal will only have Tobiano offspring, because Tobiano is the only gene that the foal has. On the other hand, lets say we breed a solid patterned mare to a Tobiano stallion and they both pass on their respective pattern gene. This foal now has one solid and one Tobiano gene, and can have both solid or Tobiano offspring.
