This filly is dark bay (crooked blaze and a lip-snip; no other white markings.)
Mom’s black-bay (lots of chrome.)
Dad’s blood bay (small star.)
She. Is. Dark. Bay.
But, as her winter coat’s coming off, and I’m spending plenty of time rubbing on her, I see that she’s got lots of white hair/roaning around her flanks and rump! And some up on her neck!
Color/genetics gurus – WTF??
What color pattern/throwback controls this? Would this mean she might pop out in Birdcatcher spots or something?
It’s cute, but … perplexing!
PS I just looked up her pedigree - not a single gray in her 5 gen-x. You have to go back 3 lines to even find a chestnut!
Rabicano and/or Sabino 
Well that’s a fine how-do-you-do Jb!
BUT WHAT DOES THAT MEAN???!!
I don’t know nothin’ about no rabicano. Or Sabino.
!!!
What controls this and what does it mean??
OP I have the same thing! My mare shed out the same way as a two year old and it is coming back again (3). The BO tried to tell me she’s going grey (she’s not). I can get a picture, but it won’t be for a week (at the trainers). Do you have a picture of yours? Her baby pics are in my signature line, but you can’t see it in those. Overall her base coat color is the same, however.
I thought the 'cinos 
had white? All she has is a little bitty star.
Her mother was a chestnut and her sire a bay.
What’s your horse’s breeding? Mine: http://www.horsetelex.com//horses/pedigree/608147
I have always admired red bay roan cow ponies, but this is a bit weird. She’s also got dark dapples this year (what causes those)?
Funky!
I thought a roan, like a gray, HAS to have a gray parent.
JB can you help us noobs understand the science that governs rabicano?
Are you actually alarmed by this? lol
Rabicanos tend to have a lot of roaning on the belly and flanks, and usually at least some white hair at the base of the tail.
Sabinos can have a lot of roaning all over, and often have a lot of white.
My bay gelding has both rabicano (from mom) and sabino (from mom and/or dad) although mostly he looks like a bay with two white socks and a star. The white spot on the underlip, the roaning around the star, and the outline of his socks belie his sabino-ness. I wish he had a real skunktail, just because it would be so fitting, but alas he just has a few white hairs.
Here’s a rabicano (who also has sabino): http://www.allbreedpedigree.com/skunktail
An article on sabino: http://en.wikipedia.org/wiki/Sabino_horse. If you click on this, keep reading, because the genetics of only one type of sabino has been worked out so far.
Found this on rabicano: http://equinegenetics.blogspot.com/2010/02/rabicano-not-roan.html (from Riddlemethis’ blog)
And this also on sabino: http://equinegenetics.blogspot.com/search?q=Sabino
I would love some strategically placed bling, but all I get is white hip hairs sigh. [I’m so kidding]
Mine has no white on the tail. Lots of white hair on the flanks, less on the belly. Definitely not a sabino.
Does the roaning emerge more and more with age, or is it basically what it will be? Just thinking how greys get whiter…
Genetics are fascinating.
[QUOTE=TrotTrotPumpkn;6948188]
I would love some strategically placed bling, but all I get is white hip hairs sigh. [I’m so kidding]
Mine has no white on the tail. Lots of white hair on the flanks, less on the belly. Definitely not a sabino.
Does the roaning emerge more and more with age, or is it basically what it will be? Just thinking how greys get whiter…
Genetics are fascinating.[/QUOTE]
My horse didn’t have any white in his tail until he was a few years old, so it may show up yet!
I had a chestnut gelding who was Sabino with roaning. Large blaze and chin white, two hind socks one extending up above hock. He was registered as ‘grey’ on his papers and did have a grey parent but he was not grey. He had the roaning always, but every year he got more white hairs. It was not isolated to his flanks but all over. It was such a beautiful colour. The roan hairs were super silver and gave him an overall shimmer, almost metallic.
I also have a bay yearling colt who is likely Sabino, maybe Rabicano. He has two hind socks and chin white and has had roaning across his flanks since he shed out his foal coat. His seems to be isolated to his flanks, unlike my chestnut horse who had it everywhere.
My understanding is that roaning as a ‘side effect’ of Rabicano/Sabino is very different from a Roan horse. A true roan horse has many more white hairs and often their head and legs are excluded and stay darker. I was also under the impression that Sabino is alway expressed, a horse must have chin, upper leg or belly white to be Sabino.
Tell me about it - I got a dime-sized white spot on hind heel LOL Ok, I got lots of white hairs all over his body once he sheds, which will be from Sabino.
Mine has no white on the tail. Lots of white hair on the flanks, less on the belly. Definitely not a sabino.
If there is absolutely not a single white hair in the tail, but lots of white on the flanks and some on the belly, it’s more likely Sabino than Rabicano
Does the roaning emerge more and more with age, or is it basically what it will be? Just thinking how greys get whiter…
It’s not the same as gray, where pigment is systematically removed from all the hairs over time, but yes, Sabino and Rabicano can indeed cause white hairs to start showing up, and multiply, as the age progresses
[QUOTE=winter;6948246]
My understanding is that roaning as a ‘side effect’ of Rabicano/Sabino is very different from a Roan horse. A true roan horse has many more white hairs and often their head and legs are excluded and stay darker. I was also under the impression that Sabino is alway expressed, a horse must have chin, upper leg or belly white to be Sabino.[/QUOTE]
Yes, totally separate, all 3, though there COULD be a link between Sabino (in some form) and Rabicano - not ruled out.
However it’s not true that a true Roan will have many more white hairs, nor that the legs and head will always be excluded Nor that a horse must have the white you described to be Sabino. Sabino can be extremely minimal, just a low coronet for example. Upper leg white is actually not very common with Sabinos, and in fact, many Sabino’s I’ve seen with white coming above the knees/hocks are also likely Dominant White (just to throw more into the fun mess :D).
Is there any connection to Birdcatcher spots here?
Nope
[QUOTE=JB;6948277]
Upper leg white is actually not very common with Sabinos, and in fact, many Sabino’s I’ve seen with white coming above the knees/hocks are also likely Dominant White (just to throw more into the fun mess :D).[/QUOTE]
Is that true of the roany drafts with lots of white?
We used to own a TB mare who I would have thought was sabino; she was a light gingery bay with four white stockings, a big white blaze and white underlip. Before we owned her she threw a bay with even more white than her, by a dark stallion with minimal white. Her offspring had white up over the knees and hocks and a belly spot.
A belly spot on a TB is most likely Splash. Given that, the high leg white was probably due to Splash, but it’s shape could have been influenced by Sabino. If it was jagged, nearly guarantee it was high due to Splash and jagged due to Sabino.
There are drafts who are Dominant White and “roany” like I think you’re thinking of, and there are those who are a “lit up” Sabino, and phenotypically it can be impossible to tell the difference.
Ah, OK.
How long can Sabino, Rabicano, and Splash “hide” in a pedigree/bloodline? Is it always there and just so minimal that you can’t see it or can it actually skip generations?
No gene skips a generation.
But that’s different from whether it’s hiding. Both S and R can hide and then suddenly pop out quite visibly when the right combination of genetics from both parents combine.
I have learned soooo much on this forum over the last two years! I have learned in my pasture right now i have a rabicano (very expressed skunk tail and all), a sabino with three high (and jagged) white legs and a belly spot, and another sabino with four white legs and a lower lip! I musta struck the lotto! And they are all three different breeds… 
[QUOTE=JB;6950188]
No gene skips a generation.
But that’s different from whether it’s hiding. Both S and R can hide and then suddenly pop out quite visibly when the right combination of genetics from both parents combine.[/QUOTE]
I didn’t really think it did but it was the easiest way to phrase my question. So… I have an Appaloosa with four high whites (middle of the knee and bottom of the hock) and dam has NO white on her legs, sire has one rear sock to the bottom of his fetlock, where did four white stockings come from? 
(I know, the Lp gene complicates matters to say the least…)
The Equine Tapestry blog has lots of great information about colors and how patterns can interact. I think OP may especially enjoy this page of tagged articles:
http://equinetapestry.com/category/sabino/
This is an article about anomalous little white spots:
http://equinetapestry.com/2013/01/24/little-white-dots/
