A Note about Sugarbush Draft Horses

I see it over and over again, and no matter how many times it's said, it's still wrong. "Sugarbush Drafts are just an Appaloosa Draft Cross". Uh.... no. The Sugarbush Draft Horse was a breed created many years ago in Ohio. While the initial cross was made using Percherons to Appaloosas, in the many generations following, the breed has been solidified into a consistent type. Saying these horses are "just" a draft cross makes as much sense as saying that AQHA horses are "just" a Thoroughbred cross, American Cream Drafts are "just" a dilute Belgian, or that Morgans are "just" a grade.

Sunday, July 18, 2010

Champagne and Pearl

Sounds like a fancy dinner with a rich man!  But Champagne and Pearl are 2 different genes that cause similar color changes.  They are located on different places on the DNA (I think they are even on different chromosomes, but am not positive) and they are inherited differently.

Champagne is easy, it's a simple dominant gene.  This means a horse either shows it, or it doesn't have a dominant copy.  Horses who are homozygous (CHCH) look no different then heterozygotes (CHch).
This is my filly Amber, an origonally named Amber dun champagne mare.  Here you can see the metallic shine associated with this gene, as well as the blue and pumpkin colored skin. Amber does not have the striking amber colored eyes often seen with this gene, but many champagne horses have diluted eye color.  Foals are born with light blue or green eyes, and they will darken to grey (for green) or amber to light brown (from blue).

It's the why part that is so interesting!  The Champagne gene causes dilution of the pigment producing ability of cells.  In other animals (it's well documented in mice) this gene is responsible for eye pigment. Interesting that champagne came up in comments a few days ago in regards to eye color!  Seems that is the main function of this gene.

Now, the "why" part gets a bit technical.  What basically happens is that the pigment cells are supposed to "take in food" and "put out color pigment".  At least that's what normal cells do.  In Champagne, the cells are on a diet.  The molecules that should enter the cell are not easily able to enter, and thus, the pigments produced are, well... deficient of everything they need.  This means weak pigment for both red and black.  Because these pigment cells are all over the body, all pigment, from eyes, to skin, hair, and hooves, is affected.

Why the shine?  Well, no where has any one seemed to cover that.  It's my personal opinion that it's the shade of color, and they way human eyes pick up reflections of light.  Red horses have more shine then grey horses, as an example.  Not all Champagnes are shiny.  Mine is in the middle of the spectrum, but I have seen both shiny and dull coated champagne horses.

In past generations, Champagne horses were often mistaken for creme dilutes.  Many gold Champagnes (chestnut with Champagne - ee ??(unknown agouti) CH?) were thought to be palominos.  This confused a lot of breeders as to the inheritance of the gold colored horses.  I have also been asked by "old timers" if a palomino was "pink skinned or dark skinned".  I suspect that this was how to differentiate between Champagne and Creme before people knew that DNA even existed.

Of course, I'm so amazed at how many breeders knew there was a difference!  I'm not sure I would have been so astute!

Now, Champagne dilutes both black and red pigment in a horse.  My filly shown above is genetically:
E? Aa Dd CHch.  I know this because her sire was E? aa Dd CHCH while her dam was E? A? dd chch.  Now... did those strings of letters make a bit more sense after reading the last few entries?  If they didn't, the sire was a black dun champage (E? aa = black, Dd = dun, CHch = Champagne) while the dam was bay (E? A? = bay, dd = no dun effect, chch = no champagne effect).
Here you can see all of the dilution in progress.  She is dominant for extension (E?) so she is black based, but she carries a dominant agouti (Aa).  Because her dam was bay, and her sire recessive for bay, we know that she can only be a heterozygote for this gene.  This means that her base coat is bay.  The yellow areas are from the dilution of red pigment, while her silvery legs are the dilution of the black pigment.  Now, she shows signs of Dun, and most likely inherited it (I haven't gene tested her) and the line is almost tone on tone, so very hard to see or photograph:

Yet, the line is similar in color to her leg markings, which I have both an untouched, and a photo shop edited version of below, to help you see the markings:
Click for larger.

So, the dun would have also diluted her pigments.  Dun can dilute both red and black pigment as well, so the additional dilution effect of champagne on top of that, means a silver and gold horse, in this case.  Normal Amber Champagne horses (those without dun) tend to have darker points then this mare.  I highly recommend this site http://ichregistry.com/colors.htm for pictures and more information on champagne.  They explain it wonderfully!

Pearl on the other hand, is a very similar looking appearance on the horse.  Both Pearl and Champagne are known for the metallic look, but Pearl gives a stronger shine then Champagne.  Pearl is an incompletely recessive gene.  Pearl can be traced through baroque bloodlines, including PRE and Lusitano horses.  As a result, many of our stock breeds have this gene.  It was first found in the Barlink bloodline of Paints!

This is a famous image of a striking pearl colored horse, taken from this link:
Now, incompletely recessive... what does THAT mean?  Well, it's similar to incompletely dominant.  One copy of Pearl gives an effect to the horse's hair coat, although it is almost imperceptible.  Just like Creme on Black is rarely noticed by the naked eye, heterozygous pearl (PRLprl) horses often are thought to be normal colored.  Pearl also really likes Creme.  Horses with a creme gene, and a pearl gene appear to be double dilutes (like cremello, perlino, etc), such as this black, creme, pearl carrying horse:
Notice how this horse looks very similar to a Smokey Creme (E? aa CRCR) horse?  Instead, this horse's genome would be written as E? aa CRcr PRLprl).  Yes, I skipped the genes that don't apply here, such as dun.  If the gene is not mentioned, then it's assumed to be in the "wild type" state, or in other words, what is "normal" for most horses.  For dun, that means "no dun" or dd.  Pearl only affects red pigment on its own, but with the presence of the creme gene, it can dilute both pigment types.

Often, genetics testing results will list a horse as PRL/N.  Another way to write this would be PRLprl.  In the case of pearl horses a horse exhibiting the homozygous recessive (prlprl) is what we would call a "pearl horse".  A horse "without" Pearl would be written as "PRLPRL".  Backwards to what is commonly seen in other genes.


So... ready for your test?  What color is this horse?

EE aa crcr chch PRLprl

A bit of a tricky one!

15 comments:

  1. I'm not ready for the test yet! Our Norman is a overo champagne, with a deeper color mane and tail - his tail actually has a whole mix of colors from a lighter sun-bleached gold to a very deep rich chocolate, and he has the classic amber eyes - very startling the first time you see them. No dun characteristics. He does have darker legs as well - once again more of a chocolate. He does have that metallic sheen, and the oddest thing is that his haircoat seems to just shed dirt and stains - he cleans up easier than any horse with white I've ever seen - I wonder if that is caused by the difference in the hair cells as well?

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  2. The first Champagne horse I ever saw was before the color had a name. He was the funniest lavender gold color, which I now know is really a classic champagne (champagne on black), and he had grayish green eyes. From that point on I have always had a fascination with Champagne horses.

    My Amber also sheds dirt easily, but oddly, she can have some skin conditions as well. Such as when she sheds her hair, she gets flaky skin, almost like rain rot trying to clear up. I am not sure if this is related to the color, as I really don't know many champagne horse owners!

    Kate, does your guy have any skin issues? I have found that Amber does the best on higher fats, and her coat really shows a difference in the smallest changes in her health. If she is a bit under the weather,or stressed for any reason (i.e. change in routine) she doesn't shine.

    I've heard so much about the genetics of this color of horse, but so little about anything else around it, so have no idea if we just got lucky on the dirt, or if that's common.

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  3. Edited the post a bit to try and make the test easier.

    ReplyDelete
  4. It would be interesting to find out if champagne hair has a different character than regular hair, leading both to the metallic shine and the dirt-shedding power. Norman has no skin or coat issues - he's always had a beautiful coat. He doesn't really shine in the winter - it's more a summer coat feature. The only skin issues he has are related to his white areas - he's had a carcinoma on his white eyelid and tends to sunburn easily there and on his pink nose!

    On the test - the horse is a black with (probably almost imperceptible) pearl - perhaps just more metallic in appearance.

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  5. Good to know that it's only Amber then! We wondered if it was something that went with the color, or if it was simply something SHE has.

    And yep, you nailed that one. I would have taken "black" as an answer, but you even got all the details. I think you're a genetics dork too!

    More tomorrow of course.

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  6. It's not fair! Kate seems to have a head start on the test every day! Course, I had a good excuse today--I went on a two hour trail ride! But I was going to say the same thing as Kate.
    My amber champagne tobiano filly never had any skin issues either, other than the fact that she grew more winter coat than any horse I've ever owned. It served her well when she sold to northern Alberta last fall. She has a pale tan body with chocolate points, but only showed the "sheen" in the height of her summer coat. Here's a link (copy and paste):
    http://1.bp.blogspot.com/_h8Tp8AXdL5I/SkjsguQwV8I/AAAAAAAABF0/6FCVaMuFCl0/s1600-h/DSC_2931.JPG
    One of her baby pictures was featured on the cover of the Champagne Horse Journal last year. She was a sweet girl, half sister to my dun, Kate.

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  7. Sorry, EvenSong - I'm a bit of a test nerd and it's hard to hold me back!

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  8. Don't worry Evensong, we just know that Kate's a fellow genetics dork now.

    And nice mare by the way. My champagne horse doesn't grow hardly any winter coat, of course, she was born in Texas, so hasn't really had a need for one (she's also a blanket baby, LOVES her winter blankey).

    I haven't learned yet how to photograph the Champagne horses and capture the beauty of their color. In pictures they are always "meh" colored, but in person everyone drools over mine.

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  9. Good to know that it's only Amber then! We wondered if it was something that went with the color, or if it was simply something SHE has.

    And yep, you nailed that one. I would have taken "black" as an answer, but you even got all the details. I think you're a genetics dork too!

    More tomorrow of course.

    ReplyDelete
  10. Edited the post a bit to try and make the test easier.

    ReplyDelete
  11. The first Champagne horse I ever saw was before the color had a name. He was the funniest lavender gold color, which I now know is really a classic champagne (champagne on black), and he had grayish green eyes. From that point on I have always had a fascination with Champagne horses.

    My Amber also sheds dirt easily, but oddly, she can have some skin conditions as well. Such as when she sheds her hair, she gets flaky skin, almost like rain rot trying to clear up. I am not sure if this is related to the color, as I really don't know many champagne horse owners!

    Kate, does your guy have any skin issues? I have found that Amber does the best on higher fats, and her coat really shows a difference in the smallest changes in her health. If she is a bit under the weather,or stressed for any reason (i.e. change in routine) she doesn't shine.

    I've heard so much about the genetics of this color of horse, but so little about anything else around it, so have no idea if we just got lucky on the dirt, or if that's common.

    ReplyDelete
  12. Hello, I have no idea if you'll see this or answer this but I have a now 10-12(can't remember exactly right now) Appaloosa mare, and she is VERY shiny and from what I can tell has the champagne dilute because shes got gold-ish hair...but also silver...basically think full metallic color. Even her spots are metallic with some being a metallic orange to copper to brownish. She also has some sort of(what I can only think of/find reference too) as brindling...along with the "dark mascara/eyeliner" look everyone refers to but never classifies for me. Here are links to some pics, they're not spectacular because my camera isn't very good but the first shows how bright/shiny she can get and the second better shows her markings...though the few stripes you see on her barrel are on her neck as well. oh, and she has a really wavy tail(not sure that that particularly matters)

    http://i1116.photobucket.com/albums/k578/ExquisiteIllusions/Appaloosa_Mare_Stock_by_xxViatrix.jpg

    http://i1116.photobucket.com/albums/k578/ExquisiteIllusions/Sweetie.jpg

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  13. I don't know...Black?

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