I found the COOLEST site! Ok, This site has a function thingy mabob (yep, it's obvious that I'm not technical, eh?) that allows you to click on genes, and see the results of various combinations. It's not perfect (Appaloosa is ALL wrong) but it's pretty close for base colors. Just click on the link, or go to http://www.jenniferhoffman.net/horse/equinegenetics.html and check it out.
I can't believe I've never seen this before. It's cool, and very useful for showing people how the genes stack up on each other's effects. Granted, I couldn't figure out how to save a picture of a horse with Rabicano, so a seal bay with silver will have to do instead.
Now, Rabicano is a white pattern gene. This pattern is a roan type pattern, but it's inherited separately from classic roan. Rabicano is refered to as RB, and it's genetics aren't well known. Currently we discuss it as if it's a simple dominant gene, but again, no one seems to be positive of that, and I can't find any definitive research on it. I think this is a case of horse people knowing the trait exists, and no one has gotten around to studying it yet, because it's not THAT popular (i.e. won't bring THAT much money to the university).
So, Rabicano is most often seen as a racoon tail, or a stripped are at the top of the tail. While there are varying levels of expression, rabicano seems to always affect the tail hairs, resulting in a pattern like this:
First Picture from here, and second picture from here.
As you can see, the first horse has some scattered white hairs in the flank area. The second horse though, shows extensive white markings traveling up towards the front legs across the ribs, as well as a very white area on the top of the tail.
Like all pattern genes, Rabicano can be inherited with other patterns. Yes, it is possible to have Classic Roan with Rabicano, although in some cases it is hard to be sure of this. The best way to check for rabicano, is to look for the stripes in the tail, because white ticking on the sides can be so minimal as to be impossible to see, or it can be covered up by other white markings such as tobiano, or appaloosa.
Because there's no real knowledge about the genetics of Rabicano, I can't go into inheritance of it. There is a similar trait called a gulastra plume. This results in a horse with a white or greyish colored tail. Here is an example:
So, today's test............
What color would this horse be?
EE aa CHch Dd RNrn
A Note about Sugarbush Draft Horses
I see it over and over again, and no matter how many times it's said, it's still wrong. "Sugarbush Drafts are just an Appaloosa Draft Cross". Uh.... no. The Sugarbush Draft Horse was a breed created many years ago in Ohio. While the initial cross was made using Percherons to Appaloosas, in the many generations following, the breed has been solidified into a consistent type. Saying these horses are "just" a draft cross makes as much sense as saying that AQHA horses are "just" a Thoroughbred cross, American Cream Drafts are "just" a dilute Belgian, or that Morgans are "just" a grade.