Color/Genetics experts....

[attwoode]

I'm just now getting into Sabino genetics and understand that their are some varying thoughts on this, but for discussion sake, I'm going to make some assumptions. I understand that there are several potential causes of Sabino phenotype and that genetic testing or test crossing are a reliable method of Identifying the Sabino1 gene. I'm going to assume that Sabino1 follows single gene, semi-dominant inheritance. Also, lets assume that the roaning i mention below is related to the Sabino1 gene, and not other roan genes.

That being said, if a mare is a heterozygous carrier of the Sabino1 gene and exhibits characteristic blaze, socks, and "sabino roaning" - are the patterns of her markings and roaning closely linked to the Sabino1 gene (these same traits appear similarly in all heterozygous offspring from a cross with a non-carrier) or is the appearance of similar pattern and presence/absense of sabino roaning inconsistent among these offspring. More clearly stated, if a mare showing sabino pattern including roan produces sabino offspring do they inherit the roan too? If they inherit the blaze and socks, are the patterns of foals similar?

 

[Joanne]

We were fortunate to be part of the University of Kentucky study that found the Sabino 1 gene. As you mentioned there are believed to be other sabino genes, but there is currently no test for these.

Here are some known SB1 miniature horses (they were genetically tested and found to be heterozygous carriers).

This full body photo is the sire of the other two stallions. He also carries at least one other sabino gene that adds additional roaning to the coat.

The sb1 sabinos characteristically have bald faces, some mascara around the eye, and frequently patches of color around the eyes. Eyes can be blue or brown (mine seem to be dominant for blue). You can also see the intensity of the blue eyes in these photos. All of our "pure sabinos" have high white stockings, belly white (quite high in the sire's case), color and/or mascara around on or both eyes.

Ours have proven to be quite dominant for the trait and almost always pass it on.

They are excellent crosses with all the other pintos genes (frames, splashed white and tobianos) as they add a sparkle to the pattern that makes them unique.

"If a mare showing sabino pattern, including roan, produces sabino offspring do they inherit the roan too?"

If we are talking about sb1, I would say yes. They could be carrying another sabino gene that we can not test for at this time. We have examples of these on our website.

"If they inherit the blaze and socks, are the patterns of foals similar?"

No more than in any other potential genetic cross.

Feel free to contact me if I have not fully answered your questions.

 

[Mona]

Hi Joanne. Since there is a test available for Sabino 1 only, as you have described it in your post, and since it is said that there are other sabino types also, but that there are not tets available for them yet, can you describe the characteristics of the other "types" of sabino they refer to?

Edited to add: Also, you mentioned the blue eyes as that being common in the Type 1 Sabino. So are they saying they suspect (or maybe have proven) that the blue eyes, once thought to have been related to Splashed White or Frame pattens only, can also be found as a sabino trait too, or are they blue only because they carry one of the other patterns with the Sabino 1?

 

[Joanne]

Hi Mona,

I would NOT say that blue eyes and sb1 go together. My sire which I bought from Knollac farm has been dominant for producing blue eyes and his foals are just now old enough to breed, so we will see what they do. I do believe he is a pure sabino, but carries several sabino genes. He has also been dominant at passing the sabino genes on, though he is heterozygous for sb1. As there is no test for splash white I cannot prove that at this time.

Sabino eyes can be either blue or brown, which is what I said in the original post.

I have over 50 head of horses here and have produced well over 100 foals. There are several kinds of blue eyes. I really see a difference and these sabino blues are different than the darker blues I see with the tobianos, for instance. Many horses produce blue eyes for various reasons; i.e. cremellos, dilutes (palomino and buckskin), silvers. At the risk of being flamed on this forum, I do not believe in the theory that the horse must carry splashed white in order to have blue eyes, as has been suggested on this forum. There are too many variables, and too many genetic traits we cannot test for at this time.

Here are several mares that both the researchers at U of K and we thought would be sb1 BUT did not test as sb1. U of K have kept these samples to try and find one of the other sabino genes.

Note the FLAT blaze that curves around the eyes. These are all unrelated to each other.

This red mare appears to be a roan, but neither sire or dam were.

This is the belly mark on Pacific Justin Time, and his full body photo. He also carries frame. But everyone thought he was SB1 too.

His testing was negative.

This is the dam of the black, bald faced stallion above. She is a frame sabino (sb1), but likely carries other sabino genes as well.

Note that one eye is brown and one is blue. Also note the facial patch.

MANY OF THE MINIATURE HORSES THAT ARE LISTED IN THE PEDIGREES AS "ROAN" ARE REALLY SABINOS.

ALSO, MANY LISTED AS "SILVER" OR "WHITE" HORSES ARE ACTUALLY SABINOS OR MULTIPLE PINTO GENES AND NOT REALLY WHITE AT ALL.

Sorry this is a photo heavy post, but I actually kept this short.

 

[Shari]

Maggie is from two tobiano sabino parents but the only color she got was the Sabino ticking, like she wanted white pinto markings but didn't quite make it...is hard to see the white hairs...and tiny wee bit of white on her forehead.

Can see the tiny wee bit of white on Maggies forehead here.. had just clipped her in this photo and did not go a very good job.

Her Daughter Theia, is Tobiano Sabino(was tested).. is funny.. she just has the ticking on her face like her mother.

 

[Joanne]

Appaloosa-like pigmenting is also common on sabinos , and these can be called appaloosa markings when they are not (no appaloosa in the pedigree). This can occur anywhere on the body, but is common on the genital areas (around the vulva or on the penis).

Here are a couple of examples around the muzzle. Irregular triangular patches and dots are common. These darken significantly as the mare nears foaling. I cannot explain this, but it is apparent:

Sabinos are also confused with greys. There is a grey-like sabino that gets more white hairs during parts of the year and nearly (or does in some cases) whites out. The two heads of the mares above which are also frames, appear to be solid white part of the year and bright colored roans when their new hair comes in. It is this grey-like sabino that is often miscalled a grey in the registration pedigrees. The new grey gene testing can rule this out.

This black mare does also not test for sb 1 and I own both sire and dam and neither are grey horses. She is barely a roan when her new hair comes in and gets more white during the summer. This is her in summer. She is now six years old and should be completely white if she was a grey. She should also ever get more black when her new hair comes in if she was a true grey:

Here is her dam:

 

[Songcatcher]

Joanne, thank you so much for your posts and pictures on this subject. This is the most informative post I have read on Sabino.

 

[Joanne]

You are welcome.

One of the problems of registration color/patterns is that they are phenotypic, which does not keep up with current genetics. I understand it, but it is still frustrating. I have a sold white filly that carries frame, sabino and tobiano. She is pure white with blue eyes. She can only be described on her registration papers as a solid white. Many of these in the past were likely listed as a cremello in the registry, though they were not double diluted horses.

The "Silver" Sabinos: Fake Silver genes

Often these sabinos appear to be a silver when they are born and darken in as they age. These both tested as SB1 Sabinos, but other sabino genes as well ??? Here are a couple of examples:

Casanova was sold to Australia as a silver. The yearling photos were taken here and the four year old in Australia. The silver test was not yet available when he was born. He is not a silver. Neither sire nor dam are either. You can see how the incredible markings show even more as they age. This is an excellent example of a sabino with their jagged markings up on and on their legs.

A second example:

This is Pacific Taboo that is a 2008 colt. Here is a newborn photo and one after he was older and clipped out. He is even darker now. This colt is a frame/tobiano and tested NEGATIVE for sb1, but clearly carries a sabino gene that we cannot test for at this time. This type of sabino darkens as they age:

 

[Mona]

The first horse in the last two examples here...do you have newborn and/or first clipped pics of same horse? Have you had this same patterning/type in sorrel? The reason I ask, is last year, I had a colt born out of my loud/wild sabino mare. He was a red dun actually, but he shows some of this jagged white up his legs and under chin, and he of course also had the wide blazed face. When I clipped him, and after her grew his coat back, he was SOOOOOOOO light you could barely see his color any more. Again, I KNOW he is not grey, but sure seemed to lose his color, I suspected to the sabino roan. Do you think that he will get darker color back in as he ages then??

 

[Knighthawke]

This was so informative!

I just recently got a buckskin leopard stallion that I was told was caring the sabino gene. I have not tested him but saw his dam and she looks sabino. But I didnt see it until I saw his baby pictures. Now he looks all white with buckskin spots. He is my avatar. I guess I need to have him tested for sure. But he doesnt have blue eyes.

Barb

 

[Bunnylady]

I would NOT say that blue eyes and sb1 go together. My sire which I bought from Knollac farm has been dominant for producing blue eyes and his foals are just now old enough to breed, so we will see what they do. I do believe he is a pure sabino, but carries several sabino genes.

Joanne, are you suggesting that there may be more than one locus producing the sabino-type pattern? Because what you said here doesn't add up with what I have heard. My understanding is that there are possibly multiple alleles in the sabino series, only one of which currently has a test for it. If that is so, then your stallion can carry no more than two different sabino genes, not several as you have stated above.

And, while I'm being a pain

, I have a problem with your use of the term "dominant." I think you may be a little confused, at any rate, you are going to confuse people that are reading your post. When speaking of genetic matters, "dominant" just means that, if the gene is present, you will see its effects. It can't "hide." It has nothing to do with the likelihood of the gene appearing in offspring. While it is interesting that a preponderence of your stud's babies have had blue eyes, the odds of it happening should be 50/50 (unless he has multiple genes at multiple loci that can produce blue eyes.) At any rate, saying that he is "dominant for" producing anything is an incorrect use of the term.

 

[midnight star stables]

This is a GREAT thread! Thank you!

I have three horses I feel carry the sabino gene. I am not sure if they would be sb1, but I do feel they have sabino traits.

I have a question regarding my 2007 gelding. Similar to the sorrel posted above he has random white hairs on his flanks where body colours are present. Also on the ridge of his neck and front legs, he clearly roans out. Is sb1 the likely cause? I wouldn't think so after Joanne's first post, but??

I don't think I have a good picture off hand, I'll get one tomorrow.

BTW, Joanne, Casanova is just about the most beautiful horse of yours that I've seen! He is Stunning!

:wub

 

[Joanne]

Mona, at your request, here are the newborn foal photos of Casanova that you wanted. I have not had one is sorrel (red), but we have a high number of homozygous blacks here and have far more blacks and bays with few reds produced. This colt is homozygous black:

BunnyLady I am NOT a geneticist, but have been fortunate enough to work and interact with some of the best in the world (Ann Bowling, Sponenberg, and Samantha Brooks who discovered the SB1 sabino and developed the test.

Mona I think that your sorrel colt has the whiting (looks like greying) sabino trait. He will show his color twice a year when his new hairs come in. They rest of the time he will have so much roaning that it will be hard to see the color. Make sure you take registration photos when he is showing his color or he will be mislabled.

These "fake silvers" are what get darker as they age.

 

[Songcatcher]

Again, I want to emphasize that this has been the most enlightening discussion I have read on Sabino. Joanne has presented the most compelling evidence I have seen on the possibility of blue eyes being associated with Sabino.

I do want to point out though that the way the white falls off to the side of the face on the foal above is typical of Splash. Of course nothing can be proven regarding that until a test is developed for Splash. I have read they are working on one. I can hardly wait.

Thank you again Joanne for your VERY excellent examples.

 

[Joanne]

For those that may be interested in additional information here is the link to the Sabino Horse Registry which has a lot of photos:

Sabino Horse Registry

This is from their site and they have a number of photos. Look under "About Us". The photos may be of help to you.

I know MY horses and their lines and had the opportunity for both Samantha Brooks (again, the founder of the sb1 gene and its testing) and the late Ann Bowling to review my horses. We test all our horses here as new tests become available that fit their criteria. This costs us hundreds of dollars a year, but is very useful for us in designing our breeding program, and for our clients who leave knowing what they have.

We are also looking forward to a splashed white test and will be using that on our horses when it is available.

This is a quote from the Sabino Horse Registry site which may be of use to you. You will note that either eye color is acceptable.

[SIZE=18pt]ThPatterns[/SIZE]

* This page is graphic intensive, please be patient while loading *
WHITE MAXIMUM SABINO: (MW)[SIZE=10pt] Horse born white with dark or blue eyes. Skin is mottled or pink. A Maximum Sabino may have ink dot spotting throughout the body. These spots may be limited to skin or may carry over to actual dots of color within the coat itself. [/SIZE]

ROANED SABINO, NO SPOT: (RN)[SIZE=10pt] Horse that develops a roan coat with evenly distributed roaned hairs at ratios of 50% or more throughout to include the head area. White markings to include excess white on face, legs, belly or jaw are allowed so long as no independent spots are located on body trunk. Horses carrying the true roan gene must also carry distinctive Sabino markings to qualify for this category. [/SIZE]

MEDICINE HAT/WAR BONNET: (MH) [SIZE=10pt]Horse should have white body with a colored skull cap. Color in tail, chest plate, flank patch is allowed. Roan ticking preferred within spots. Edges of spots must be irregular or roaned to indicate the pattern is caused by the Sabino action. Ink dots are desired on white areas. Horses of this pattern must show proof of at least one Sabino parent and no Tobiano or Frame parentage. [/SIZE]

LOUD SABINO: (LS) [SIZE=10pt]Horse should have spots, splashes, or lacing of white throughout the coat. These horses should also have facial and leg white evident. Ink dots are allowed and desired within this pattern. Roaning is desirable. Frame patterns are not allowed. [/SIZE]

MODERATE SABINO: (MO) [SIZE=10pt]Horse must have high white stockings on one or more legs with white running up above knees or hocks, belly spots and preferably jaw and /or throat splashes. Facial markings such as bald or apron face is desired however horses without excessive face white are allowed provided they meet the other criteria of Moderate Sabino. Roaning, roan ticking, and/or roan patches are allowed. Chin and/or lower lip spots highly desired. This pattern must display at least two of the following: Belly spots, high white stockings above knee or hock, lightning strike leg markings whether attached or disattached from leg white; leg patches, bald or apron face. [/SIZE]

MINIMUM SABINO: (MI) [SIZE=10pt]Horses who do not display loud or moderate Sabino markings but who have minimal leg white and/ or facial white with roaned edges, irregular shapes or edges, leg markings coming to a point. Minimal roan ticking is allowed and desired. Chin/lower lip spots are desired. This category must display at least one of the following: chin spot, lower lip spot, roan ticking, ink dots, jaw or throat spots, leg markings that come decidedly up to a point and/ or are irregularly shaped, an odd white spot on legs or body without other spotted markings. [/SIZE]

SPLASHED WHITE: (SW) [SIZE=10pt]Horses who appear to have been dipped in white. These may NOT be horses of Overo parentage. Typical patterning includes apron faces with blue or partially blue eyes, white legs, white belly spotting, white underjaw and throat spotting or splashes. These horses may have an isolated spot on the body trunk or may exhibit this pattern on top of a laced or roaned body pattern. Crisp lines are allowed so long as the pattern indicates Sabino. All classifications of patterns may be over any recognized coat color. There will be no discrimination between base colors when judging. Sabino patterns mixed with other known spotted patterns are disallowed. [/SIZE]

 

[Mona]

Thanks Joanne...that just amazes me at how light his mane was as a young foal and how dark it got!! Thanks for sharing!

 

[attwoode]

Thanks everybody. After seeing all of the variations of sabino 1, I remember seeing a solid black mare with just a small patch of white roaning on body (it almost looked like a scar), she was bred to a red "roan" stallion with a blaze and minimal white leg markings. I suspect they both may have been sabino. They produced a heavily roaned mare that was very light red or maybe palomino. This mare was bred to a solid black stallion and produced a very gold palomino with gorgeous high socks, blaze, small belly spot, and no roaning. Althoug hwe can't know for sure which of the sabino complex genes may have been involved, at least it answers my original question. It appears that although the inherited sabino markings can be very similar among relatives, then can produce very different phenotype whether because of multiple genes being involved or differences in expression of the same gene.

Thanks everyone for contributing to this post!

 

[Joanne]

This horse which is listed as:

"SBH Jack Be Silver, true blue roan 30.5" stallion, picture taken @ 9 years old" by Fantacsix on another post,

may actually be a misidentified Sabino stallion (IMHO).

These not really roan horses, like the misidentified silvers, greys, solid whites, and appaloosas can prove to be challenging when researching a sabino's color pedigree. Without photos like this one which gives us a substantial clue we would be lost. The sabino is perhaps the most misunderstood pinto gene.

A "True Roan" does not have white hairs in the head, mane, tail or legs. This horse has it more or less uniformly throughout the body. Roans are born roan, and do not grey over time.

 

[Bunnylady]

Ok, let me rephrase my question, and see if I can get someone to answer it. I have heard the term "sabino complex." What I thought I understood that to mean was a single gene, at one locus (with possibly multiple alleles,) that sets the sabino pattern, and a number of genes at other loci that modify its expression. Now it sounds like a different situation entirely. The scenario that I seem to be hearing now is one of several mutations, at totally unrelated loci, that result in very similar patterns that have all been lumped together and called "sabino." An example of this would be if the Clydesdale "sabino" and the Arabian "sabino" turned out to be at completely different loci, and were, in fact, unrelated and separate patterns that just happened to look alike. Which is the current theory? Does anyone know?

 

[Joanne]

It is my understanding from rereading the genetic study results that there are more than one gene believed to be involved. I have a busy day here today, but I will type out some of the passages from the final submitted scientific paper that explains their findings. The scientific paper is 15 pages long. So I will only share a few excerpts.