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View Full Version : Color genetics experts -- 2yo dark bay Tb shedding out with roan 'snowflakes'! WTF??!



Hunter's Rest
Apr. 19, 2013, 01:43 PM
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!

JB
Apr. 19, 2013, 01:47 PM
Rabicano and/or Sabino :)

Hunter's Rest
Apr. 19, 2013, 02:20 PM
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??

TrotTrotPumpkn
Apr. 19, 2013, 02:26 PM
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)?

Hunter's Rest
Apr. 19, 2013, 02:32 PM
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?

grayarabpony
Apr. 19, 2013, 02:33 PM
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

TrotTrotPumpkn
Apr. 19, 2013, 02:36 PM
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.



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.

grayarabpony
Apr. 19, 2013, 02:49 PM
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.

My horse didn't have any white in his tail until he was a few years old, so it may show up yet!

winter
Apr. 19, 2013, 03:07 PM
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.

JB
Apr. 19, 2013, 03:22 PM
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??
Genetics controls them :D

Ok, but seriously - yes, it's the Sabino genes (only SB1 is testable but there are almost for sure more than one, probably quite a few more), and the Rabicano gene(s) of which none are testable, we just go by phenotype.

Rabicano (see the other recent thread) doesn't make white markings, but it does, in the extreme form, put a "skunk tail (http://www.whitehorseproductions.com/images/horsecolor/oddities/skunktail_rabicanotb.jpg)" on the horse (white hair starting at the top) and puts roaning - white hairs in the coat (http://25.media.tumblr.com/tumblr_m8ovu7rVNf1rzjxmao1_r1_400.jpg) - along the flanks and barrel. in more minimal form it can literally be a couple white hairs in the tail and some scattered white hairs in the flanks

Sabino is responsible for a lot of the "normal" white markings on a horse. Socks with jagged edges are usually Sabino, for example. But it can also be hidden, or extremely minimal


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?
You're right about roan (or really Roan) and gray, but other patterns can mimic Roan, such as Sabino and Rabicano.


I would love some strategically placed bling, but all I get is white hip hairs *sigh.* [I'm so kidding]

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



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.
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).

Hunter's Rest
Apr. 19, 2013, 03:30 PM
Is there any connection to Birdcatcher spots here?

JB
Apr. 19, 2013, 04:43 PM
Nope :)

grayarabpony
Apr. 19, 2013, 08:26 PM
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 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.

JB
Apr. 19, 2013, 09:19 PM
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.

grayarabpony
Apr. 19, 2013, 10:20 PM
Ah, OK.

Miichelle
Apr. 20, 2013, 05:07 PM
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?

JB
Apr. 20, 2013, 05:32 PM
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.

HorseKrazy
Apr. 20, 2013, 06:01 PM
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.... :D

Miichelle
Apr. 20, 2013, 06:29 PM
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 didn't really think it did but it was the easiest way to phrase my question. :D 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? :confused: (I know, the Lp gene complicates matters to say the least...)

poltroon
Apr. 20, 2013, 06:39 PM
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/

JB
Apr. 21, 2013, 09:47 AM
In the case of the appy mare with high whites, it's simply a combination of the right expression genetics coming together, and/or the lack of suppression genetics. You say the dam had no white legs - any face white?

Miichelle
Apr. 21, 2013, 10:45 PM
In the case of the appy mare with high whites, it's simply a combination of the right expression genetics coming together, and/or the lack of suppression genetics. You say the dam had no white legs - any face white?

Attached are the best photos I could find of my mare’s sire, dam (with her as a foal), and her (as a 4 yr. old). It looks like her sire DOES have some white on his legs but not much, can’t tell if he has a star. Dam has a star. Yes, Patoka is a few spot but (in person) you have always been able to see her stockings. About the time she turned eight or nine she started “reverse roaning”, I’ve only came up with a couple of references to it online, she’s getting ticking everywhere she has dark skin. Every spring she sheds out slightly darker, she’s registered as a blue roan fewspot but she’s” roaning in” as a dark bay with four white stockings and a snowcap blanket. None of her original black spots have changed or her “lightening marks” on her legs.

http://i124.photobucket.com/albums/p21/michelletjk/WapSpotWho-Ad-1_zps40dee33b.jpg

http://i124.photobucket.com/albums/p21/michelletjk/Patoka2002-1-1-1_zps3b4e8f74.jpg

http://i124.photobucket.com/albums/p21/michelletjk/0412091548-2_zps5720e1b5.jpg

Sorry to hijack the thread! :)

ETA: Patoka's dam isn't ribby in the photo, she actually has "stripes"!

californianinkansas
Apr. 21, 2013, 11:20 PM
This is such an interesting thread!

harvestmoon
Apr. 22, 2013, 01:37 PM
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/

And I recommend her book, too (more are in the pipeline).

poltroon
Apr. 22, 2013, 02:53 PM
And I recommend her book, too (more are in the pipeline).

Definitely. The Equine Tapestry is terrific and contains a lot of historical insight about breeds and breeding, like the tidbit that you can tell the current dominant color of a breed from its mare base, and the trendy colors from the stallion base. She's been researching the deep history of breeds for some time, and has collected a stunning amount of information that is not always in tune with the conventional wisdom we grew up with. If you ever have a chance to hear Lesli Kathman give a talk, I highly recommend it. I'm quite looking forward to the next book.

(disclaimer: I'm a longtime member of her fan club. :D )