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SEAL Brown - discussion.

Here you go ACC. Bay mare from two seal parents. [attachment=1]mimi april2006 2.jpg[/attachment] As a foal with mum, sire is the same colour as mum. [attachment=0]mimi and nenah.jpg[/attachment]

duncentralstation Tue, 08/25/2009 - 19:50

Nutritional deficiencies can indeed be responsible for washed out coats in horses, too. But what I'm talking about when I say fading black are blacks who lighten after spring shedding regardless of sun exposure. These shouldn't be called fading blacks, probably, but maybe "light blacks"?

Either way, some non-black, red tinged pigment is showing through, and as we know with clear red bay horses, red is expressed visually on the body regardless of whether they are "EE" or "Ee". Most browns who don't also have pangare, also exhibit red pigment in their soft areas. So we do know that otherwise "black" horses can express red pigment.

But it because ALL horse can produce phaeomelanin (red pigment), or is it that agouti does flip a switch from eumelanin to phaeomelanin when it is in dominant form (A or At)??

BTW, if you want to see a non-black black (tested to be just black, not smoky black, not black silver ... nothing but just black), check him out here ...
http://www.tamarsventures.com/Prophet.h…" onclick="window.open(this.href);return false;

He has darkened in the past couple of years, but he is still never truly black to the naked eye. I owned his non-fading, without a doubt black (EE) sire for a while, and this horse's chestnut silver dam has produced a non-fading jet black in the past. So what's up with this stallion and his other siblings by the same black sire is a mystery to us!!

accphotography Tue, 08/25/2009 - 19:51

I think she means an EE A_. How can a horse with the "inability to produce red pigment" look red? That's agouti's job.

I was always told that agouti essentially kills the eumelanin producing cells, and in horses, that causes them to default to pheomelanin.

duncentralstation Tue, 08/25/2009 - 19:56

[quote="accphotography"]I think she means an EE A_. How can a horse with the "inability to produce red pigment" look red? That's agouti's job.

I was always told that agouti essentially kills the eumelanin producing cells, and in horses, that causes them to default to pheomelanin.[/quote]

Exactly! But how does that work? To me, the whole "defaults to red" isn't logical. I'm not saying it isn't true, mind you. But by what genetic or physiological process does this happen?

I understand that the cream gene acts to dilute red pigment in heterozygous form, for example. That's fairly simple. But if cells are programmed to be black, how can the 'default' to red when agouti blocks the hormone stimulating receptor ... blah, blah, blah ...

Know what I mean??

Or is it actually that all horses are already producing red pigment, but when the extension locus is "E" at both places, the red pigment is covered by black pigment? But in the absence of the ability to produce black pigment (either due to "ee" or "A-") we get to see the red pigment?

Like I said, I'll try to contact someone who can answer this more accurately tomorrow! :o)

duncentralstation Tue, 08/25/2009 - 20:01

[quote="accphotography"]I've seen some Friesians look like that, or even redder.[/quote]

Yeah!! And what's bad is that this guy was born before the silver test. We (his owner and I) thought he had to be some odd expression of black silver. She had him tested for cream, since his sire was out of a line that had cream a couple of generations prior behind two blacks. But he tested "Ee aa" and N/N for cream. Worse yet, we were seeing a ton of Rocky horses this same coloration out of known silver dapple parents. So we were so sure ....

But, then we got to eat crow, because this stallion, his dam and a few of his siblings were included in the silver study and the researchers sent her results before the study was published ... he was definitely NOT silver. Bummer!! But we accepted it and publicly announced the results. He had never bred a mare at that time, so it's not like she was promoting/guaranteeing him to be a silver to mare owners, mind you. She was very upfront that it was not proven, just suspected.

Anyway, this particular expression of black seemed to be common in the Rocky breed as far as we saw. We just don't know what is causing it.

accphotography Tue, 08/25/2009 - 20:15

Well I think pheomelanin is produced the whole time, it's just covered by eumelanin.

Horsegen knows this, she explained it on the other forum several times.

duncentralstation Tue, 08/25/2009 - 20:31

[quote="accphotography"]Well I think pheomelanin is produced the whole time, it's just covered by eumelanin.

Horsegen knows this, she explained it on the other forum several times.[/quote]

OH! So you're saying that my first post was actually accurate, then?!

BTW, no disrespect to this forum or the original forum site, but I generally don't have time to keep up with this site. I have slow dial up service and am quite often busy enough with my own Yahoogroups lists, clients, etc.

It's just a time thing ... not personal!!

At any rate, I surely never saw Horsegen's posts on this exact topic before. But thanks for letting me know that she has explained it essentially the way I did in my first post today.

I don't like to be wrong (who does?!), but if and when I am, I want to learn it right! I would rather find out right away that I'm wrong and fix my knowledge base with the accurate info. :)

accphotography Tue, 08/25/2009 - 20:55

Oh no, I didn't mean to say you'd missed it. Shoot I've read it several times and I STILL don't know if I'm relaying it correctly. Not to mention it's probably been a year since she did that.

Andrea Wed, 08/26/2009 - 11:05

I think I'm not in this deep enough...
If a horse tests E_ and A_ meaning it's bay... Does brown really need it's own distinction?
Or is there a third gene causing it to be brown: Need to be black with agouti AND a different gene making it brown? That's the only case I could say where it would matter, but that's just me...

accphotography Wed, 08/26/2009 - 11:26

It matters if a person is trying to breed for this:
[img]http://www.angelfire.com/on3/TrueColour…]

and they keep getting this instead:
[img]http://colormorgans.tripod.com/devinegu…]

In super simplistic terms it might as well be another gene in addition to agouti, because the horse will test positive for agouti, but it won't look normal bay if it has this "other gene" (which is really just another allele of agouti).

My Lace is homozygous agouti. But I would LOVE to know if she has the ability to produce wild bays or browns instead of just red bays.

jafo Tue, 01/05/2010 - 16:08

Well I'm new here so I'm not sure if you guys think it's ok to post to a thread this old or start a newer one with what seems to be a similar topic...so I am guessing, set me straight if this isn't your normal protocol!

I have a very dark buckskin filly out of a (tested) perlino mare and by a brown (by AQHA standards) stallion (I'm aware that brown=bay). The filly looks brown herself but just to calm any naysayers, I had her tested as well and she is buckskin.

Anyway, what I find might be interesting to this thread is that I had a lady post to me on the pleasure horse forum that she believed there to be such a thing as smokey brown just like smokey black. There is (according to her) some gene that makes a brown horse brown (as opposed to just bay) that is not dilutable (like black), and creates what she calls a smokey brown. This color would test out like a buckskin as she said the brown gene would be at a different locus and in order for the brown to even show up, the horse would have to be bay "first."

Just wondering what anyone thought of this theory or if anyone thinks that she could be talking about the seal gene without knowing it?

duncentralstation Tue, 01/05/2010 - 18:50

[quote="jafo"]Anyway, what I find might be interesting to this thread is that I had a lady post to me on the pleasure horse forum that she believed there to be such a thing as smokey brown just like smokey black. There is (according to her) some gene that makes a brown horse brown (as opposed to just bay) that is not dilutable (like black), and creates what she calls a smokey brown. This color would test out like a buckskin as she said the brown gene would be at a different locus and in order for the brown to even show up, the horse would have to be bay "first."

Just wondering what anyone thought of this theory or if anyone thinks that she could be talking about the seal gene without knowing it?[/quote]

Sounds like she's talking about the brown agouti allele to some extent, but then again, it does seem that she's saying a brown horse has an "A" plus something else to make them brown on top of being bay?

That really doesn't work ... not based on the expression of the color (in my opinion and based on my own years of studying the inheritance of brown, etc.), nor based on the science. I realize not everyone is aware of the research done on the brown allele, though.

The thing is, almost all brown buckskins are born looking rather clearly buckskin. They aren't born looking super dark already most of the time. So it's clear that they are "dilutable", at least early in life. And at least on the parts of their bodies that are not darkened to black by their brown gene.

Just as there is a range of expression among browns, ranging from "sooty bay" looking to nearly black looking ... there is also a wide range of expression for brown buckskins. Just because some are darker than others doesn't mean the darker ones are caused by a different (agouti) gene necessarily.

No ... browns are not bay first. I think some folks get the wrong impression/idea of what might be causing the brown expression because they don't understand how the standard agouti test works. And that's understandable because it is not at all explained by the labs offering the test. They don't explain it because it's just easier to report the results.

Now, the lady is right that there is a gene that makes a brown horse brown. But it's not a gene that is in addition to the gene that makes a horse bay. It's a gene that is present *instead of* the bay mutation of agouti. It's the "At" mutation of agouti. And it's the "A" mutation of agouti that causes bay. They are different at the genetic level.

A horse that is visually (and genetically) brown (At/a or At/At) cannot produce offspring that are bay (A-) unless the are bred to a mate who has and passes on an "A". If a brown were bay plus something else, then brown horses would routinely produce bay offspring with mates that are "aa". But that's not the case. Some of them may produce lighter expressions of brown that some might want to call "sooty bay", but they are not bay ... they are lighter expressions of "At", and will test as "At" with the specific brown test offered by Pet DNA Services.

It is important to add here that a horse can be visually bay and also have a brown allele, though. The horse is A/At, although with the conventional agouti test, the results will be reported as "AA". That's only because the conventional agouti test actually detects "a". If only one "a" is found, it's assumed the other must be some form of "for agouti", and if no "a" is found at all, then it's assumed both must be some form of "for agouti". It cannot tell us which form of agouti, though.

Last I knew, the research that identified the mutation for At was stalled due to funding issues, so has not yet been published to the best of my knowledge ... which is really quite a shame, but I'm not wealthy, so cannot help fund the research.

Feel free to share what I wrote with that lady if you like. I am not being critical of her in any way shape or form. I just happen to have the inside scoop on the "At" research, have read (and mostly comprehend) the published studies on many color discoveries, including the study that originally identified a mutation of agouti .... and it actually did not identify the "A" for bay ... it identified "a" for "black distributed over the entire horse if the horse is not ee".

dakotakdq Tue, 01/05/2010 - 21:26

I have just bred my mare to a brown roan stallion that has tested pos for agouti and has sired only black and bay foals to date, no browns.

is he just a really dark bay that looks brown?

dakotakdq Tue, 01/05/2010 - 21:45

bay, chestnut and a black gone grey had bay foals. he is also homo for black.
heres a baby pic of him - what colour is he? bay roan or brown roan?
I recently had him tested at U C Davis and he tested EEAa

accphotography Tue, 01/05/2010 - 22:10

Are you certain the gray was black prior to graying?

Visually he is definitely brown. I think it is being masked in his foals by the mare's colors. I'd like to see him tested though.

duncentralstation Tue, 01/05/2010 - 23:04

[quote="dakotakdq"]I have just bred my mare to a brown roan stallion that has tested pos for agouti and has sired only black and bay foals to date, no browns.

is he just a really dark bay that looks brown?[/quote]

He is visually quite textbook brown expression, IMO.

Are you sure the foals were bay? Keep in mind that brown foals are born bay looking in general. When they shed their foal coat, if dark brown, the shed out fairly dark. If lighter brown, they may shed their foal coat to appear "sooty bay".

Of course, some of the foals could be bay if they got an "A" from their dam.

dakotakdq Wed, 01/06/2010 - 03:45

I didnt think of that either! lol. the bay ive seen is a true bay but her mum was the bay.
I bet the others are browns!

So if hes brown why does he test pos for agouti? sorry to sound dumb :oops:

duncentralstation Wed, 01/06/2010 - 06:11

[quote="dakotakdq"]I didnt think of that either! lol. the bay ive seen is a true bay but her mum was the bay.
I bet the others are browns!

So if hes brown why does he test pos for agouti? sorry to sound dumb :oops:[/quote]

Not dumb at all!! I have answered this question SO many times. There is no way it can be a "dumb" question if so many people ask it!! In fact, the rejuvenation of this thread has inspired me to finally get around to writing an article on agouti ... hopefully explaining it in a way that people can finally understand, clearing up a lot of confusion where black, red and agouti are concerned.

But I'm not going to leave you hanging, waiting for the article.

You said his agouti test results were "Aa", correct? Assuming I understood that correctly, the answer to your question is ....

[b]Technically and literally he did not test positive for "A" ... he tested positive for "a" at one locus, and negative for "a" at the other locus The conventional agouti test can NOT detect any dominant form of agouti (A or At). The original agouti study did NOT find any dominant form of agouti ... [i][u]it only found the recessive form "a"[/u][/i]!![/b]

In short, the conventional agouti test looks for "a" ... the loss of function of agouti.

If the test detects that the horse has "a" and "a", then test results are reported as "aa".

If the test detects that the horse has just one "a", it is *assumed* by default that the other locus is a dominant form of agouti, and results are reported as "Aa".

If the test detects NO "a" at all, it is assumed both are dominant forms of agouti and the results are reported as "AA".

The test CANNOT tell you if the presumed "A" is a true "A" for bay, or if it is actually "At" for brown.

Pet DNA Service of Arizona found a mutation of agouti recently that is associated with the brown phenotype, though, and he does offer a test for "At" (brown) which can tell a person if their horse has "At".

Hope this helps!!

Dogrose Wed, 01/06/2010 - 08:39

Its is really interesting watching this discussion as I have a small animal colour genetics viewpoint and small animal colour genetics looks at agouti, nonagouti and suchlike in a different way.
No one has mentioned melanism yet, this is found to have been caused by a mutation on the MC1r locus in felids and mouse species (same locus as chestnut allele) not the agouti locus but affects agouti making the black more extensive causing the phenotype to be anything from just a dusky version of the original to almost self black looking. It is not on the same gene locus as agouti, where self black, tan and agouti are found. It seems to be very common in a lot of species of wild animal. I think it is dominant, one type recognised in fancy rats is anyway.
In small animals the progression for agouti and tan is agouti>tan>self black. So an agouti could carry self (black) or tan but not both, a tan could carry self (black) but not agouti. By carry I mean have one copy of the recessive allele with the allele not expressed phenotypically. If At in horses is tan and the tan works in the same way as agouti and tan in small animals then a horse that looks bay could carry the tan allele, being AAt, and test positive for it but not look tan phenotypically. If the tan in horses is dominant to bay then it wouldn't be analogous to tan in small animals.

duncentralstation Wed, 01/06/2010 - 09:02

LOL! Taking color genetics of two different species is so incredibly confusing because how agouti expresses on mice/rats may be very different than how it expresses on horses, for example.

MC1R, as you know, encodes for the Extension locus, and the Extension locus is where the "E" or "e" comes from in coat color genetics coding.

I'm covering this in the article I'm working on, actually, because I don't think one can fully understand how agouti works if they don't understand how black/red works. And technically, red is actually considered yellow in genetic terms. Technically, it's eumelanin (black pigment) and phaeomelanin (yellow pigment). But since phaeomelanin is expressed visually as a red color in horses, we just refer to it as red pigment to make it easier to understand, I guess.

The Extension locus determines if a horse CAN produce black pigment or not.

Agouti, when in one of its dominant/active form, blocks the production of black pigment. It does not cause the production of black pigment ... it blocks it from being produced.

In some species, this causes a banded appearance of the individual hair shaft. If you were to pluck a coat hair and look at that single shaft of hair you would see a band of black, then a band of color, then a band of black, etc.

In horses, agouti works a bit differently...
The bay (A) mutation of agouti blocks the production of black pigment on the body, but not at the point areas .... i.e. mane/tail, ear rims, lower legs and nostril rims.

Because Agouti does not cause the production of black, it has no effect on "ee" horses ... after all, they have no black pigment being produced for Agouti to affect.

The brown (At) mutation of agouti is less aggressive, so to speak. Though it has a range of expression, the most classic expression is that "At" blocks the production of black pigment only on the soft areas ... i.e. belly, muzzle, insides of upper legs, flank, etc. ... allowing the production of black pigment on more of the body of the horse than as seen with the "A" mutation.

You wrote:
"If At in horses is tan and the tan works in the same way as agouti and tan in small animals then a horse that looks bay could carry the tan allele, being AAt, and test positive for it but not look tan phenotypically. If the tan in horses is dominant to bay then it wouldn't be analogous to tan in small animals."

"At" in horses is indeed the equivalent of tan. It's my understanding that the "t" in "At" stands for "tan".

Horses that have tested to be A/At do express the bay phenotype because the bay "A" is essentially more aggressive than "At" and restricts the black more, effectively masking the presence of the "At" in that particular horse.

jafo Wed, 01/06/2010 - 13:42

[quote]The thing is, almost all brown buckskins are born looking rather clearly buckskin. They aren't born looking super dark already most of the time. So it's clear that they are "dilutable", at least early in life. And at least on the parts of their bodies that are not darkened to black by their brown gene.[/quote]

THANK YOU so much for clearing up the Agouti testing. I had no idea. I was living under the impression brown was dark bay and it was all the same, with possibly some modifiers that were as of yet untestable or something add'l going on.

Referring to the quote above, I am posting some newborn pix of my previously mentioned filly. She never, ever looked buckskin, and was more similar to what I've had black or brown foals born as than anything. (In fact when she was still wet from birth she LOOKED black!) I have dozens of pix of her but this only lets me list three and I'm sure you can get the point w/o so many examples ;-)

duncentralstation Wed, 01/06/2010 - 15:40

SHE is a great example of just why I used words such as "almost all" and "most of the time" .... because sometimes you do get one who isn't clearly buckskin. ;)

Based on the earlier pic you posted and especially the side shot of her you just posted, I might just as well have guessed smoky black.

BTW, in the earlier pic of her that you had posted, she looks more like a smoky black, but you said she has been tested, right? Or was she only tested for cream and not for agouti to verify that she's not "aa"/smoky black?

Lovely foal!!

jafo Wed, 01/06/2010 - 16:32

[quote="duncentralstation"]SHE is a great example of just why I used words such as "almost all" and "most of the time" .... because sometimes you do get one who isn't clearly buckskin. ;)

Based on the earlier pic you posted and especially the side shot of her you just posted, I might just as well have guessed smoky black.

BTW, in the earlier pic of her that you had posted, she looks more like a smoky black, but you said she has been tested, right? Or was she only tested for cream and not for agouti to verify that she's not "aa"/smoky black?

Lovely foal!![/quote]

Thank you! I like her :D Yes she was tested for everything available from Animal Genetics (meaning not At), even though the dam was tested AA previously and I knew she wasn't smokey black. She is :

Date Received: 11/6/2009
Horse Name Breed Red Factor Agouti Cream
Kara Mel Krymsun Quarter Horse EE Aa nCr

I KNEW she was buckskin but I thought for a simple $40 or whatever it was, I could (perhaps) quit answering the million questions about how I knew it, you know? Also I was told that I would need this proof to get her buckskin papers as well since she looks brown. I haven't done that yet though.

NOW with this new info (new to me LOL!) about the At gene/seal brown, I am really wondering if that could have anything to do with her (Kara's) color and if so how that applies to future breedings. I know that even though the sire IS brown, she only received an "a" from him, since the mare didn't have one to give. The "A" had to come from the mare and I'm wondering if there's any reason to think it might be an At instead? Of course then I have the fact that is mare is absolutely one of the lightest perlinos I've ever seen. She's registered cremello (I tested her on a hunch) and has nearly no color in her mane, and is virtually the same as my other mare that truly is cremello. Seems not to make sense.

For a small farm with only 7 horses, does anyone think I have my share of color oddities LOL???

duncentralstation Wed, 01/06/2010 - 16:46

Since you know for a fact that the mare is homozygous for agouti and the filly HAD to have gotten hers from the mare, it's a given (in my opinion) that at least one of the mare's agouti is "At" and that she passed that on to the filly.

I say it's a given IMO because of the filly's phenotype.

The mare tested "AA" .... and we can be reasonably sure, based on the filly's phenotype that one is "At", but the other one could be "A" (bay). Or she could be homozygous for "At". Hard to say for sure without testing. Or if she should be bred to a stallion who is "aa" and produce an obviously clear coated buckskin, then you could reasonably assume the other is "A" (bay).

While I've certainly seen a good share of perlinos who have rust colored manes, tails and leg points, I've seen quite a few who pass for cremellos, too. I can't honestly say that I have an intelligent answer for why that is, though :o)

Those "odd" colored horses keep things interesting, eh?!

jafo Wed, 01/06/2010 - 16:53

They certainly do Nancy! I thought breeding this mare to OHK would "lock up" a buckskin or palomino for me, and in fact, I had people waiting to purchase a buckskin colt from this cross should I get so lucky...I hate to be a pessimist but I seem to be the only person I know that can mess up a sure thing LOL :flower

accphotography Wed, 01/06/2010 - 19:08

JMO but brown based perlinos tend to be MUCH darker than bay based... so yup, I bet she's AAt as opposed to AtAt.

jafo Wed, 01/06/2010 - 19:27

[quote="accphotography"]JMO but brown based perlinos tend to be MUCH darker than bay based... so yup, I bet she's AAt as opposed to AtAt.[/quote]
Thanks :-) I appreciate that feedback...I wondered if anyone had paid attention to those statistics. I just took the mare to GA last weekend or I'd pull hair and do the new At test just to see.