# Color Questions and A Small Game



## tempest (Jan 26, 2009)

This weekend I watched one of my area's local horse shows and I noticed a few interesting coat colors and patterns. I don't know a large amount of horse coloring and a little about genetics, so if you would be so kind as to identify the colors of the horses pictured and explain to me what the satin gene is and how it is represented. And just for kicks I've included a few pictures of two horses I know that show just how strange and strong genes can be.


















The Paint in this picture.



























And now for the genetics, can you guess what the relation between these two horses is?
Horse #1









Horse #2









And together from the front and rear.


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## haviris (Sep 16, 2009)

1. buckskin
2. grulla
3. gray tobiano

Not sure what you're asking on the palominos.


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## Kayella (Feb 11, 2012)

Well horse #2 looks to be a grulla paint. Horse #3 is a fleabitten grey paint. 

As for the genetics, I wanna say horse #1 is dam of horse #2


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## Chiilaa (Aug 12, 2010)

The "satin" gene is only theorised, and lots of people don't believe it exists at all. It appears to be more of a pre-disposition to show a shiny coat as part of good health, combined with other things such as base colour etc.


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## tempest (Jan 26, 2009)

The first horse, the buckskin, and another horse down there actually looked like they had been painted with molten metal. It doesn't show in the buckskin photos and I was not able to get a picture of the other horse. It didn't look like the normal shiny coat on a healthy horse. Do you know what would cause that type of shining then if the satin gene is only hypothetical?


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## Chiilaa (Aug 12, 2010)

Good health and a lot of grooming.

For what it's worth, I do think there is something that does make some horses more prone to being shiny than others, but I think it will be a combination of genes and predispositions toward shininess rather than a single gene that says "make coat shiny".


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## Tintara (May 27, 2012)

If we're thinking about the same thing it's called iridescence. Having seen samples of hair from both highly iridescent and matt coated horses under a microscope it is pretty conclusive that the degree of iridescence is directly controlled by the internal structure of each individual hair shaft. This trait is passed on genetically. Perhaps that is what they mean by 'satin'.

Also, the dilute coat colours, in particular champagnes and pearls, seem to have a higher % of horses exhibiting extreme iridescence than do the base coat colours although of course there are examples of extreme iridescence in the base coats as well. It has something to do with the distribution and modification of the pigment granules in the individual hair shafts in the dilutes. 

If you want the address of a website that has some superb photos illustrating this pm me and I'll give you the URL.


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## Valkyrie1977 (Jun 20, 2012)

Completely agree with you, Tintara. I'm soon to be the owner of a beautiful gold champagne dun mare and every champagne I've seen looks like they've been dipped in a bucket of Show Sheen. The gold champagnes can look like a "high gloss" version of those lovely palominos


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## Tintara (May 27, 2012)

I've seen hair samples from a gold champagne under a microscope too and the structure is very similar to that of other highly iridescent horses.


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## Chiilaa (Aug 12, 2010)

But that's how colours change. By re-distributing the structure. That doesn't mean there is a satin gene, just that some colours have higher iridescence.


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## Tintara (May 27, 2012)

I'm talking about the actual physical structure of the medulla within the hair shaft rather than pigment distribution and the size of the pigment granules. The latter two characteristics for sure are caused or changed by the various dilution genes ie cream creates smaller pigment granules and distributes them towards the tips of the hair shaft whilst dun distributes pigment granules down one side of the shaft leaving the other side translucent hence that muted coat appearance of duns. The pigment distribution in a champagne's hair is similar to that of a cream dilute and homozygous pearls are probably similar again.

However, the physical structure of the medulla itself has very little to do with colour genes - there are iridescent dilutes and there are non-iridescent dilutes. Highly iridescent dilutes have the same type of hair structure as highly iridescent non-dilutes and the same for non-iridescent dilutes. It has to do with the width of the medulla within the cortex of the hair shaft, how fractured or 'layered' it is and therefore how much light is able to be refracted through each hair shaft. 

Highly iridescent horses have very narrow, fractured medullas that allow a lot of light to pass through the hair shaft (iridescence). Non-iridescent horses have very wide, very dense medullas which take up most of the cortex and prevent light refracting through the hair shafts. If a horse also has darker pigment granules floating around in the cortex these have a glitter like effect which adds to the overall iridescence and gives off those flashes of light you sometimes see in a highly iridescent horse depending on how the light hits them.

I suspect that with some of the colours ie champagne and pearl, where iridescence is reasonably common across most individuals with that dilution, the internal hair structure as above that permits high iridescence has now been 'bred' into that colour. As both champagne and pearl can be traced back to a tiny handful of original carriers it isn't unreasonable to assume that with such a small original gene pool, things like hair structure were easily passed on to the majority of offspring carrying those dilution genes. Who in turn bred it on until today those genetic attributes have become part and parcel of the colour itself.

Dun, cream and silver on the other hand have any number of common ancestors or have been around for so long that their genetics are much more diverse. So we see both iridescent and non-iridescent cream dilutes for instance.


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## Chiilaa (Aug 12, 2010)

Don't get me wrong. I do know that there are hairs that have greater iridescence than others. I also believe it is genetic (everything is genetic lol). I don't, however, think there is a single gene responsible for it though. I think it will be a combination of several different things that turn it on instead. 

One only has to look at an Akhal-teke to see that there is something going on which is making the hair so iridescent. And since most specimens of that breed exibit it, there is sure to be something behind it that is genetic. I have not had the privilege to examine hairs under a microscope, and it isn't something I can see happening any time soon, but I trust that your explanation is the correct one.


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## haviris (Sep 16, 2009)

I believe there is a 'satin' gene, I found a horse pic on craigslist of a buckskin w/ a super shiny coat (it is on my other lap top that crashed recently), and he did not look overly healthy either, so I don't think it was a result of good feed and grooming.

I don't know that it is a single gene or what, I just know something makes some horses have that extra shine.


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## DrumRunner (Jan 26, 2011)

As of right now, scientifically proven, there is NO such thing as a "Satin Gene".

Just no, there may one in the future but until then, I, like many many people, will not see it as a real gene.


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## LovesMyDunnBoy (Aug 11, 2011)

Just a comment, the first horse in a dun. Not buckskin.
_Posted via Mobile Device_


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## Chiilaa (Aug 12, 2010)

LovesMyDunnBoy said:


> Just a comment, the first horse in a dun. Not buckskin.
> _Posted via Mobile Device_


What reason do you say this for? Can you tell me what you can see on the horse that points to dun?


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## LovesMyDunnBoy (Aug 11, 2011)

In the second picture it has what APPEARS to be a dorsal stripe, could be dark countershading, but I believe it's dun.
_Posted via Mobile Device_


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## Poseidon (Oct 1, 2010)

It's countershading. If it were a dun, there would be barring on the legs, which there clearly is not.


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## haviris (Sep 16, 2009)

Nope, still say buckskin. Does not look like a true dorsal, just counter shading, and doesn't appear to have any other dun factor.


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## LovesMyDunnBoy (Aug 11, 2011)

My neighbors horse was a dun (on his papers) without leg barring? I cant see too well either, I'm on a cell. So it could very well be counter shading
_Posted via Mobile Device_


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## Poseidon (Oct 1, 2010)

Papers are not a very good thing to go by. My BOs have a "blue roan" that is most definitely the brownest roan I've ever seen. And DrumRunner's black mare is registered bay.


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## DrumRunner (Jan 26, 2011)

Poseidon said:


> Papers are not a very good thing to go by. And DrumRunner's black mare is registered bay.


True story.. Lark is very clearly not a bay but her AQHA registration papers say she is a bay..I am having her tested UC Davis and when I get the results back I can send the results to AQHA and have the color changed on her papers.

My "bay"


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