dun on bay vs dun on wild bay

[motorgypsy]

Got these photos and though some of you might like to see the difference.

Brilliant is the product of a flame colored orange/red bay plus pangare and a grulla dun. His body is pale gold and he has very very dark points. His great grandmother has brown points but I think his are black.

http://img.photobucket.com/albums/v99/motorgypsy/IMG_2129a.jpg

SloughP is a Florida cracker horse, descendant of the original Spanish horses and very closely related to the paso fino according to DNA tests. I don't know his parentage but he is wild bay plus dun, a coppery gold body color actually darker than Brilliants and you will notice that his dun stripes are NOT black but dark red. His mane and tail are very black and from the fetlock down you can see that he has black points but this wild bay gene seems to add an additional dilution to the points. His dorsal which is very prominent is also dark red, not black.

http://img.photobucket.com/albums/v99/motorgypsy/IMG_2136a.jpg

This and other genes could explain why dun seems to pop out of nowhere in foals. If it is a separate gene and is diluting the dun markings to the point where the horse is registered as bay or buckskin the dun could express in the foal with full intensity. One more thing to confuse those of us who love color coat genetics!! :roll: :roll: :roll: :roll:

[Carol Nelson]

Yeah, REALLY!! I'm just learning about silver, and fading black, and smokey black...and this word comes up there too...

pangere

So explain what this means.

[motorgypsy]

I'll check the spelling CarolN but it's the mealy gene. the one that gives a horse cream colored flanks, muzzle, underbelly and is very common in draft horses. OK it's pangare and it appears to be an incomplete dominant gene also since two of them give more cream color than one.

Here is what one website has to say about it.


The Pangare, or Mealy, Modifier

This is a subject that is the center of much discussion and dissension.
In the past this has been suggested as a single gene that causes a bay to have the "wild donkey" look, a chestnut to have the pale muzzle, underbelly, etc. like the typical Haflinger or Belgian, and a black to be a seal brown (also known as brown, dark brown, black bay and dark bay.)
However, newer research has proven this theory false. See the Base Colors page for a genetic explanation of seal brown. Now that there is a test for the "a" allele, and we know that seal browns do not test "a", they cannot be black + pangare or black plus anything. In addition, population studies had already shed doubt on the theory (there are breeds in which seal browns outnumber blacks by about 10 to 1, so if seal was caused by a pangare gene, it should occur in the majority of bays and chestnuts, as well - but it doesn't. In fact it's very rare to find a pangare-marked bay or chestnut at all in that breed..)
We have been shown photos of pangare-marked horses from parents that had none, and horses with no pangare from parents which were both pangare-marked. This rules out a simple, single gene, either dominant or recessive. It is now believed to be some sort of multi-gened effect, like flaxen. But nobody has studied it thoroughly yet, to our knowledge, so many questions about it remain unanswered.

This is the link
http://www.horsecolor.com/

[PasoVicki]

Now that there is a test for the "a" allele, and we know that seal browns do not test "a", they cannot be black + pangare or black plus anything.

Brown is one of the colors that I don't understand. Every "expert" source explains it differently (and some don't include it at all as a separate & distinct color). Some "expert" sources say brown, seal brown and seal bay are the same color, some say they're different (and some say they're just slang terms with no genetic "meaning").

What exactly are browns (and/or seal browns) if they aren't "black plus anything" as quoted above?

[motorgypsy]

In one of the sites they said the latest was that brown/sealbay/ black bay is black plus wild bay or E and A+. The test for A+ is unfortunately not yet available in this country. We have two black horses with the brown muzzles and flanks. One has a black sire, the other has a grey sire and bay mother. The info we read says if you breed two black bays you will never get bay. We're thinking we'll breed one of our black bays to our grulla stallion. We should get grulla 50% chance, black or black bay if the info is correct. The grulla though could be black bay grulla which will not have as dark a face - perhaps like Lori West's General, or the true grulla with the really dark face. I would think if the grulla is base black plus wild bay that the muzzle and flanks would have a more golden color than the body. Really interesting!

Another really interesting piece of info on one of the color site is that if the horse is sooty smutty rather than black plus + there will be bay color under the tipping of black rather than solid black or dark brown except for the muzzle and flanks.

One more interesting fact was that the fading black is not necessarily heterozygous. According to the source almost all blacks will fade whether heterozygous for E or homozygous for it. Many so called brown horses are just faded black. A very black TW stallion that we boarded with turns noticeably brown in the summer in the hot Florida sun. Our black bay also fades but oddly enough our graying black bay does not. She does not fade at all and never did even when she had no grey other than the tail. Can't tell you why though.

[Mellifluous]

In my mind, grulla is another one of those confusing "terms" that describes a shade of color rather than the genotype. I have heard it to refer to black based duns but not bay based ones.

In my mind, there are 3 basic dun colors:
bay dun, chestnut dun and black dun. They can come in a variety of shades and can be dressed up by other genes like cream or roan but these are the basics.

:D

[PasoVicki]

In my mind, grulla is another one of those confusing "terms" that describes a shade of color rather than the genotype. I have heard it to refer to black based duns but not bay based ones.


I've read that if the horse has an agouti (bay) gene, it can't be considered grullo -- a horse can be either grullo (black dun) OR bay dun, but not both. But again, no two "expert" sources seem to agree on these issues.

[Mellifluous]

if it has agouti, it will be bay and not black as the agouti will limit the black to the points of the horse.

So, you can't have a black dun horse with agouti unless you term it correctly as a bay dun. ;-)

[motorgypsy]

Ahh but there is more than one agouti gene. There is A for bay and A+ for wild bay. Black (E) plus A gives bay. Black plus A+ give an essentially black horse except for the lighter flanks and so on. The brown/sealbay/black bay in other words. They did think that these were caused by the pangare gene but the latest info says it is not. That it is caused by the A+ gene.

The latest literature says that you cannot get a bay horse by breeding two black plus A+ genes either. They will always be black bay/sealbay/brown

Grulla/o is indeed black plus dun but since black plus A+ is an essentially a black horse I suspect that if you add dun to it you will have a horse that looks grulla but has a slightly lighter head and a bit more goldish silver color on the flanks and belly. This horse will very likely be registered grulla because there is no other color description that would even come close to the real color. Lori West's General comes to mind. We are seriously considering breeding our black bay to our grulla stallion not only because I think it would be great cross without considering color but the color cross would be very interesting.

And the other thing we haven't yet discussed is if grulla is black plus dun, why are there so many shades of grulla??? Possible answer - there are other modifiers that affect just how much dun dilutes the base color including the A+ modifier

So - possible duns

black plus dun - grulla

black bay plus dun - grulla but a little different

regular red bay plus dun - anything from bay colored dun to peanut butter dun, copper gold dun all the way to pale cream with dun or what we call buckskin colored dun

chestnut plus dun - liver red with stripes to tan with darker stipes all the way to almost pink cream with stripes - claybank dun, dun, red dun, pink dun and so on

black plus creme plus dun - perhaps the silver grulla

black bay plus creme plus dun - again silver grulla but a little different

regular bay plus creme plus dun - really pale body coat and lighter points but all dun markings

chestnut plus creme plus dun - dunalino

And we haven't even considered what the sooty gene added to the above will do to the final color????

So - according to what we've read so far grulla dun colored horses can be black plus dun but can have other modifiers as well and still be categorized as grulla. And there are two very different color modifiers at the agouti locus that produce quite different coat colors but both only act on a black color based horse.

What new tomorrow???

[Mellifluous]

Also those terms are simply descriptors for the various shades of dun that can occur. They are still the same basic colors genetically.

Remember, I am the oddball that likes to refer to genotype only so you can really ignore me. There are so many regional and global terms for shades of color that it can be very confusing. I like to know the genotype of a horse, then I will look at a picture to determine what shade, etc.

a bay is a bay, no matter what shade it is it still has agouti. ;-) Like I said, there are other genes that can "dress up duns." I was just listing the basics.

Cream, sooty, roan, silver etc. can all add to the genotype of a dun horse.

[motorgypsy]

That's why I listed the genotype fist and the phenotype second. Genotype should be on reg paper - it is silly to put just the phenotype on reg papers for example.

But there is a big difference for example in A and A+, both genes at the agouti locus. They are not the same gene.

As far as dun is concerned I don't know if dun is one gene or several genes which can cause the variation in the striping and intensity. Can't wait for that test.

Sooty smutty makes a huge difference and is another modifier that needs to be listed as well as creme, roan and all the other modifiers. But we really don't know them all. Sponenberg's article at least addresses color intensity while most color genetics sources ignore it.

One reason I'm so interested in the A+ or wild bay gene is that not only do we have four duns whose color would be changed by wild bay but we have two black bays who according to the latest information we've read cannot produce red bay unless bred to a horse that carries the A gene. This is totally new information to me.

And then we can go on about phenotypes that look the same but aren't the same like silver bay and flaxen chestnut.

I'm hoping that under all these paso finos greys there is a REAL tiger horse hiding.

Imagine the thrill of the owner of the grey mare who when bred to a chestnut stallion produced a dunalino colt. Our mare is the grandmother of this colt and we considered buying him but his price was too high for his age. So the grey mare has a pale buckskin colored brown pointed dun mother and a grey father. So where in the world did the creme gene come from??? I have no clue but the colt is a very obvious palomino with very much darker gold stripes on legs, big dorsal and so on.

Here are our two black bay mares (one is greying but very slowly - she's five and her body is nearly black still)

Kalua, black bay, has a black father and chestnut mother. The mother has a bay father and chestnut mother so she could be carrying the A+ gene. Can't wait for test for it.

http://img.photobucket.com/albums/v99/motorgypsy/kahluashowsmall.jpg

Arwen, black bay going grey, has a red bay PPR mother but I think she's carrying the wild bay gene. Her father is grey son of 222. Notice how jet black she is except for the muzzle and flanks

http://img.photobucket.com/albums/v99/motorgypsy/IM000302a.jpg

[Cindy]

Kalua, black bay, has a black father and chestnut mother. The mother has a bay father and chestnut mother so she could be carrying the A+ gene. Can't wait for test for it.


Zapata was not black. He was bay.

[motorgypsy]

THANKS!! He looks black - was he black bay??? I thought that picture of you was on him??? That would explain Kalua's color.
http://img.photobucket.com/albums/v99/motorgypsy/Zapata.jpg

She really is black with the exception of her muzzle and flanks if I keep a fly sheet on her. I was trying to figure out how she got that black bay color if he was black. Where did I get the idea that he was black??? Oh - I know - from that picture of him with the I think black fresian that was his buddy????

[Cindy]

Everyone called him black but he was not. He was the same color that she is. Dark bay, black bay, seal bay. whatever you want to call it. But not black.

And yes, that is him.

[PLEASURE PASOFINO]

What is the name of the rider?.......dark blonde? light blonde? ash blonde?

[Mellifluous]

I did some asking around on the agouti thing. This is what I was told.

Apparantly it is a hypothosis that

...(postulates A+, A, At, and a alleles in that dominance order where A+ causes wild bay and At causes seal bay). There is actually not any evidence for that hypothesis. Scientists have sequenced agouti and found only two alleles, denoted A and a.

Yes, complete sequencing of the agouti gene in the horse did not reveal any At or A+ alleles. That was an old theory that does not appear to be true. We don't know what makes some bays "brown" and some bays "wild bay."

[motorgypsy]

That is what I thought also until I read it recently. Let me find the article. This is soooo interesting!
The latest from France supposedly has disputed this. OK here's a quote on the article.

http://www.mustangs4us.com/Horse%20Colors/agouti.htm

NEWS FLASH!!!
Preliminary testing by a laboratory in France indicates that a form of the AGOUTI gene ("A+" or "Wild Type Bay") may be the agent that creates the Seal Brown pattern, which has up until now been attributed to the Pangare gene working on a Black base.

Apparently, all Seal Browns so far have tested by the French lab are positive for Agouti, indicating that they are perhaps a form of very dark, sooty Wild Type Bay.

-from "The Horse" Second Addition. Authors J. Warren Evans, Anthony Borton, Harold F. Hintz, L. Dale Van Vleck.
Copyrighted 1990. On page 479-481.

However, if you breed 2 Seal Browns you don't necessarily get a Bay, which indicates that more research is needed.

- Thanks to Joycelyn Kasmir
www.DiamondJFarms.com for this information!


I'll look for the Sponenberg article again on it also. Notice this one says At was once in favor, then out of favor in favor of pangare causing black bay which has been disproved so At is back in favor again but not proved.

OK - Sponenberg says the pangare gene causes black to become black bay or seal bay but according to other articles there is now a test for the pangare gene and black bays don't carry it so that theory is disproved.

One more article


Locus Category Alleles Description Action
Basic Color Loci
The two Epistatic Loci that determine the most basic underlying color of the horse, to which all other loci are modifiers (according to current studies).
Agouti/Bay Basic A+=Wild Type Bay
A=Common Bay
a=no effect

Modifier color that limits black to the points.
This allele has no effect if it is homozygous recessive or the horse is not genetically black. Hypostatic to E (extension) or black/red locus. Multiple Dominant/Epistatic

source

http://www.mhref.com/color/genetics/loci.html

and one more quote

Brown is probaby recessive to bay; it is caused by the Agouti gene At on a black horse.

It was thought in the past that seal browns were just black horses with the Pangaré (mealy) gene, but in 2001 when the "a" allele was isolated and researched in France, none of the seal browns tested were "aa"-- showing that seal brown IS caused by an Agouti allele, and not by Pangaré.

http://www.ultimatehorsesite.com/colors/sealbrown.html

So it seems there is still disagreement over whether the A+ or the At gene cause brown color. I'll keep looking. But it does appear that the A+ is pretty widely accepted as existing in addition to the A gene that produces red bay.

[Candice Burger]

Not everyone, Cindy, I called Zapata bay.

MGs, I need some clarification please. What are you calling black bays?

There is the red gene, which determines black or red.
There is the augoti gene which determines bay on black horses.

So what is a black bay because a bay horse is genetically a black horse with the augoti gene. Are you talkinga about a different gene other than augoti?

Question for both MGs and Mellwhatshername: Could you date your references because the augoti theory for A+, A, At, a is in 1990 and there may be more recent information.

You can breed two bays and not get a bay. A bay horse can be EEAA or EEAa or EeAA or EeAa.

Only EEAA will guarantee a bay horse every time. EEAa will give a black or bay horse depending. EeAA will give a bay or chesnut horse and EeAa will give bay, black or chestnut.

[motorgypsy]

OK Candice I'll try to do a 50 cent summary which for a naturally verbose person like me is not easy!)

There appear to be at least two and very likely more genes at the agouti locus that modify black base color

A which produces red bay,

A+ or wild bay which further dilutes the points almost down to the fetlcok (see first photo) and is now speculated to produce brown/black bay seal bay as illustrated by Zapata and Kalua's photos. and described as a black horse with brown on the muzzle and flanks to a varying degree

and there is also speculation that there is an At gene separate from the A+ gene that produces black bay.

The wild bay or A+ wild bay gene is pretty much accepted as being different from A or normal bay gene. There is less evidence so far for the At gene.

I've not found definitive evidence as to which of the two A+ or At or something else produces black bay.

I believe my other post had in it that the study in France was in 2002. When I'm not feeling so lazy I'll check.

The end

Related info

There is no evidence so far that black and black that sun bleaches are different genetically. According to all the articles I've read all blacks will fade under the right circumstances.

I noted this because black bays will also fade to brown color as well as true blacks. Kalua was brown when we got her but shed to jet black excluding head and flanks the next summer and stayed black with a fly sheet on. Both EEaa and Eeaa horses (true black) will sun bleach to brow as well EEA+a and EeA+a or EeA+A (black bay)

Apparently one can tell if the black bay looking horse is produced by sooty gene on red bay or the A+ or other unknown gene because the sooty gene has black on the end but red in the middle of the hair. True black bay doesn't have this tipping effect.

[Cindy]

What is the name of the rider?.......dark blonde? light blonde? ash blonde?


You can call it whatever you want to, Caliber. :D

[PLEASURE PASOFINO]

those where the days!!!!!!!!! my friend!!!!! but I think you look better now!!!! lol

[Cindy]

I love you Caliber. Kisses, kisses.

[motorgypsy]

All right you guys can cool it!!!:twisted: :twisted: :twisted:

It is a great picture!!!

[Mellifluous]

MG - I have $10 that says your agouti info is outdated.


:twisted: :razz:

[Mellifluous]

I asked about the websites, this is what I got back...

That's pretty outdated. The "News Flash" about the French lab was simply what has been stated above...the French lab sequenced the entire agouti gene. They found that all black horses (non-bays) carried two copies of a mutation which we call the "a" allele. They also found that all seal browns carried at least one normal "A" allele. Basically what that means is that brown (or seal) is genetically the same as a bay at the agouti locus. However, no differences were found between browns and bays at agouti, so whatever causes a bay horse to darken to brown is something else, not an At allele. Sponenberg did hypothesize the existence of the At allele, which is why everyone still throws it around, but it was just a theory and has been disproven by the research.

Seal browns breed just like bays, with respect to extension and agouti. People have bred seals together and gotten bays, and they've bred two bays together and gotten seals, so the difference in shade is not something simple like a single allele. The inheritance of the seal color is probably very complex--the action of several genes working together to darken the coat.

[motorgypsy]

Whew - we're pulling all the ceramic tile in our Florida place and resetting since many of the tiles are loose. A serious pain!!

You certainly could be correct. I wouldn't even allow my students to use 5 year old studies in any of their research projects.

The info on the existence of A+ wild bay gene - I'm more inclined to believe but I could be wrong. I think there is one or several genes maybe at the agouti locus that causes the wild bay dilution like SloughP's where the points are diluted down to the fetlock and dun stripes are also diluted. Perhaps it's not at the agouti locus but it's somewhere because the effect is very dramatic.

As far as the cause of seal bay - the only thing I mentioned that was definitive was that it was NOT caused by the pangare gene. There was fairly strong speculation that it was caused by the pangare gene but it is now know that this is NOT correct. There is speculation that it COULD be caused by wild bay or even an At gene but there was nothing on any website that convinced me that this was fact. So the jury is definitely out on that one.

I was under the impression that the French study was able to distinguish between A and A+ but I haven't found an article that said that today.

As I did mention the mechanism for color intensity does not appear to understood at all so there's a lot of work to be done there.

As far as red bay not producing black bay - Bee Gee, our red bay did indeed produce Arwen, our black bay when bred to a grey. But one study said that black bays don't produce red bays when bred to each other. Don't know about that.

As far as we're concerned there are too many missing pieces to the puzzle at this point to explain many color phenotypes adequately. It is interesting that since we began studying color there have already been three new discoveries that I can recall right off the top of my head - white, pearl and champagne. I'm also not satisfied with the explanations for appy colors. Is varnish a form of greying or totally different???

But the one I'm most interested in right now is the cause of the wild bay dilution and the test for dun.