Horse Color Genetics: Tovero

To review paint markings: T=tobiano, O=frame overo, SPL=splashed white, SB1=sabino.

One fact about paint-colored horses that a lot of people don't know is that there are a LOT of paints who have more than just one kind of pinto gene in their coat. They are called 'tovero', although tovero is a frustratingly broad term, and I'll explain why in a minute. For reference, here is a true tobiano, no other paint genes involved. Just so y'all know, those spots are called 'cat tracks' and are fairly common in tobianos.

Here is a person who is partially mistaken on the horse's color. He does have tobiano, but also a different gene as well. 

Compared to horse #1's markings, this horse is actually very different. First off, I know he carries tobiano because the white crosses over his back and his legs are white (see here to re-reference the definition of tobiano). But one of the rules of tobiano that I don't think I mentioned is that tobiano's always have very predictable face markings; a dark head with a 'normal' face marking. 

Now, the above horse has a white head and blue eyes. I've been learning lately that white eyes almost always indicate some kind of overo gene. Here is where it gets confusing: which overo gene is it? Reviewing, there is frame overo, sabino, and splashed white (read more about the difference's here). There are three options, and I'll walk you through why I think this horse is tobiano + splashed white.  Honestly, I am only guessing on the splashed white, it's only a hunch. 

First off, I know it isn't sabino. Frame and splashed white both sometimes cause blue eyes, sabino does not.

The above horse I've seen many people classify as tobiano. He is very beautiful, and I love his cat tracks. However, even though he displays all of the tobiano characteristics, his irregular face markings and blue eyes give away that something else is there. I'm not even going to guess whether he is splashed white or frame overo.

Something that is really important when breeding any paint to another paint at all is to have them genetically tested for frame overo, to save yourself the heartache of an OLWS foal. Because, in thinking that the horse #2 is just tobiano, they could breed him to another frame overo, and surprise! You have a dead foal. While I've talked a little bit about genes 'hiding', frame overo is one of the easiest to hide in a paint that you may think is just any of the other patterns. Even if you are almost positive of it being just tobiano, I would still test.