Tobiano is part of the KIT gene. The tobiano allele is dominant, so a horse will exhibit tobiano with even a single allele present. Since it is KIT, it can only be present with another KIT gene if it is heterozygous. If it is homozygous, no other KIT gene can be present.
Tobiano is caused by patches of pink skin, which causes hairs that grows on those patches to be white. Foals with tobiano are born with their markings at birth, and will continue to exhibit the same markings throughout adulthood.
A horse with homozygous tobiano will always produce patterned foals. The only exceptions to this is if one of the parents passes on grey, overo, or double diluted cream.
While tobiano itself is not linked with lethal white syndrome, it may produce lethal white foals if it has overo ancestors and breeds with another career of the gene.
Tobiano is caused by patches of pink skin, which causes hairs that grows on those patches to be white. Foals with tobiano are born with their markings at birth, and will continue to exhibit the same markings throughout adulthood.
A horse with homozygous tobiano will always produce patterned foals. The only exceptions to this is if one of the parents passes on grey, overo, or double diluted cream.
- If a foal is born tobiano with the grey gene, it will only be visibly tobiano while it's young. Tobiano grey horses will grey out just like any other horse, which can cause an effect sometimes called "ghost".
- A foal born with both tobiano and overo may have white markings that combine both patterns, creating what is called tovero.
- A double diluted cream horse can simply be so lightly colored that white markings aren't easily visible.
While tobiano itself is not linked with lethal white syndrome, it may produce lethal white foals if it has overo ancestors and breeds with another career of the gene.
The first known recorded pinto patterned horses was in 1519, during the Spanish expedition to the new world. Diaz del Castillo, a Spanish historian who traveled with the expedition, described a couple of the horses as a pinto with white stockings on it's forefeet, the other as a dark roan horse with white patches.
The word "tobiano" is Spanish in origin, and believed to be named after an immigrant who brought pinto patterned horses to the new world.
The gene itself is believed to be over 3,500 years old, and is distributed among many of the world's breeds.
There used to be no direct test to determine if a horse carried the tobiano gene. After a number of years of research at the University of Kentucky in 2008, however, the gene's location within KIT was discovered and could more reliably be tested for. Today, a number of labs offer testing for tobiano, but is usually only to test whether the gene is homozygous or not.
The word "tobiano" is Spanish in origin, and believed to be named after an immigrant who brought pinto patterned horses to the new world.
The gene itself is believed to be over 3,500 years old, and is distributed among many of the world's breeds.
There used to be no direct test to determine if a horse carried the tobiano gene. After a number of years of research at the University of Kentucky in 2008, however, the gene's location within KIT was discovered and could more reliably be tested for. Today, a number of labs offer testing for tobiano, but is usually only to test whether the gene is homozygous or not.
Genes that are in bold are active on the coat. Genes that are underlined are genes that the horse may carry, but will have no visible effect on the coat.
Gene Sequence
ee · aa · gg · crcr · dd · chch · F_ · zz · stysty · rbrb · rn+rn+ · sb1+sb1+ · w+w+ · TO_ · oo · splspl · lplp · patn1patn1 · patn2patn2
Gene Sequence
ee · aa · gg · crcr · dd · chch · F_ · zz · stysty · rbrb · rn+rn+ · sb1+sb1+ · w+w+ · TO_ · oo · splspl · lplp · patn1patn1 · patn2patn2