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, September 12, 2010

The LP gene

The LP gene is the main gene needed for Appaloosa coat color.  LP stands for Leopard comPlex.  It causes a few things to happen on its own:

White Sclera.  This is the white part around the eye.  In most horses they have solid dark eyes, but appaloosas (small "a" refers to color pattern, big A refers to the breed) have a human like eye.

Then there's the striped hooves.  Not all appaloosas have striped hooves.  Some have solid amber colored hooves.  Usually, but not always, the amber colored hooves are seen on horses that are homozygous for the leopard complex gene, or LPLP.

Striped hooves are not unique to appaloosas, but they are one of the many traits.  Many horses will have striped hooves on white or partially white legs, while an appaloosa will have striped hooves on a dark leg.  The second picture shows an amber hoof that's smudged with dirt.  Sadly, I never took pictures of amber hooves, so had to go looking at what I could cut out of another picture!  The amber colored hoof on a dark leg is indicative of homozygosity in this horse.  Sadly, most of my homozygous horses have 4 white legs, which would have a "white" hoof on them anyway.

Then there's mottled skin.  The same way that appaloosas have polka dotted hair patterns, they also get spotty skin.  The amount of mottling in the skin often progresses with age, just as the horse's roaning does.  This mottling is often seen around the eyes and lips, as well as the genitals.  Basically places where there's less hair.


And then, there's the progressive roaning.  Here's an example of a horse that roaned severely in just a couple of years:

Shades of Olympic (aka Shadow) as a yearling
Then, that winter she did THIS:

As a 2 year old the next spring:
And this is where she seems to have stopped.  She looks almost identical to this as a 4 year old. ANd yes, a lot of people ask me why my white horse is named "Shadow".

But the most important thing to know about the LP gene, is that it "lights up" the appaloosa patterns.  LP is an incompletely dominant gene.  This means that with 2 recessive copies (lplp) you get a solid horse, or non appaloosa horse (paints and pintos are lplp).  With one dominant copy and one recessive (heterozygous or LPlp) you will get polka dots in the coat.  This is the type of patterning most people think of when they think "appaloosa".  And with 2 dominant copies you will get a horse with no or very few dots in their white pattern.  These are called snowcaps when there is only a white area on the rump/torso, and fewspots or near fewspots where there's white on over 80% of the horse's body.

Confused?

Lets see if this helps:

Blanket:
This little guy is a bay blanket.  E? Aa LPlp

He is heterozygous for LP (LPlp) so has polka dots in his "dense white area". 









And this is a snowcap:
Notice how this filly has the same size area of white as the colt above?  The difference is that this one doesn't have polka dots in that area, so there's more visible white.

This area is called the "dense white patterning" or a variation thereof (dense white pattern, dense pattern area, etc).

This filly is homozygous for LP, or LPLP.  And yet both of these horses would be considered to have the same "pattern" but a different 'zygosity.



And of course, a horse with 2 recessive lp alleles would look like this:
A normal solid colored horse.  Kiva, shown above, is a great example of what the LP gene does.  Many people assume that because she's solid, she's just like any other horse.  But OH NO!  Kiva there carries a leopard pattern gene.  If she had inherited just one copy of LP, she would have looked like this:
But, without the LP, she looks just like any other seal bay horse.  (That's one of Kiva's ancestors by the way, Stonewall Rebel). The important thing for breeders to know, is that a horse like Kiva can pass on that leopard pattern gene when crossed with a horse carrying at least one copy of dominant leopard complex (LP).

Ok, I think that sentence made MY head hurt.  Lets use pictures instead!

Kiva - E? Ata, lplp, PATN1? (I'll get to the pattern genes later, just trust me for now).  We know that Kiva's parents were both leopards, therefore we know that they both have at least one copy of PATN1.  Kiva could be homozygous for it (PATN1PATN1).

So, if you bred her to a horse with no pattern at birth... such as my lovely Scorch....
Scorch is E? aa LPlp patnpatn.  In other words, he's a solid roan.  Scorch was born with the appy eye, the mottled skin, and has striped hooves.  He's getting a few white hairs, but not a whole lot!

They could produce a foal that looks like this:
Who is really "Formula One Fandango" by my good friend Carrie at Formula One Farms.  Yes, he's an Appaloosa not a Stonewall Sport Horse, but I'm hoping you get the idea.

So, those solid mares from loud pedigrees are rather important in keeping the color alive in the LP breeds.  So often they are thought of as a "waste" or a junk horse, when in fact they have some of the most important genes out there.

If you keep breeding horses with "recognizable" appaloosa patterns back to each other, eventually the recessive lp gene will be lost.  There are many examples of breeding out recessive alleles due to a desired appearance.

Cleveland Bay horses are always bay.  It's extremely rare to find a horse that carries the recessive agouti allele "a".  Friesians require a black coat color for registration.  Before DNA testing, almost all of the stallions were homozygous for Extension of Black (EE).  Today, stallions must be genetically proven to be homozygous in order to be approved for breeding.  You will only find the recessive extension allele "e" in the mares, or stallons that are not accepted as breeding stock.  Soon, it will go away completely.

In appaloosa colored horses, if we breed out the recessive lp gene, we completely change the appearance of the horse.  All horses would end up looking like this:


And I don't know about you, but solid white is BORING!

8 comments:

  1. So basically what your saying is my Solid Paint mare COULD throw a baby with colour? I have no idea her background.. she's a rescue that came with no information. Vet told me Paint\QH. She does have coloured skin where she has colour,

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  2. Interesting, Heather. Appaloosa patterns are one thing I have never studied, so this is all news to me. Will you go in to the issue of the Appaloosa registry allowing out crossings, and how some say this has "diluted" the pattern--too many roans without blankets and spots--is that sort of what you were talking about there at the end of your post?

    Jeni--the pinto patterns (tobiano and the various overos) operate a little differently than appaloosa: they generally don't "hide" for a generation (though they can be minimally expressed, as in face and leg markings). Right, Heather?

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  3. Hi Evensong - Bonnie has the leg and face markings, and a bite injury grew in white... If I ever breed her it won't be for a certain coloured foal. I would be after confirmation and temperment - colour is a bonus in my book.

    Rosie on the other hand is a dappled liver chestnut - who's winter coat is almost roaned with caramel colour of belgians... One of the oddest coloured horses I've seen.

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  4. I think I get most of that - but two questions:

    1. What does a pinto with appaloosa patterns in the dark areas carry?

    2. If Kiva is lplp, what is a "normal" bay horse who has no appaloosa ancestors?

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  5. Jeni, a true solid paint can not have pinto offspring. But here's the kicker... some pinto patters show first as face and leg markings in their most minimal form.

    In other words, a horse with a really crazy blaze could be carrying frame white, and throw a VERY loud foal off of a solid stallion. It's not that both parents are solid (even though APHA says they are). Genetically, the horse with the crazy blaze is actually showing minimal frame.

    So, the simple answer is that it all depends upon the horse.

    And yes Evensong, you're right again! Of course I think you know a lot more about paint patterns then I do.

    And Kate, lets see if I can answer your questions....

    1. The pattern genes aren't an either-or type of scenario. A pintaloosa has both pinto and appaloosa genetics. It gets a bit tricky to wrap your mind around how it works, but, in a paint, the white areas are marked as "no pigment here at ALL". The colored or dark areas are marked "horse colored". Now, in those horse colored areas, the appaloosa gene can do its thing to reduce pigment, resulting in polka dots only in "pinto spot" type areas. That's because the white pinto spots were already completly erased.

    Did that make any sense? So a horse with a blanket appy pattern and tobiano, would have dark spots on its head, and areas of polka dots on its rum. If you took the polka dotted area and filled it in, you can almost imagine a solid pinto spot.

    2. All solid horses are lplp. Quarter horses, solid paints... most spotted paints too. Basically, any horse out there that is not showing at LEAST the white sclera, mottled skin, and stripped hooves, and could be showing the appy patterned coat... the horses that don't have that are lplp.

    It's the pattern genes that make the appaloosa blankets and leopards, and roans, and such. I'll get into that tomorrow (currently writing it for y'all).

    Appy patterns make most people's brains hurt. Keep the questions coming, and I hope that after the next post, it's much clearer.

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  6. >gasp< Don't you even say "boring" within several paragraphs of my darling Daltrey!

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  7. Thanks, that was the most understandable explanation of appaloosa genetics I've seen. I bred my seal brown TB to a leopard appaloosa and got a brown foal with schlera and mottling but no white patterning. She has gotten a few white hairs roaned in her coat since then but that's it.  She is fifteen years old now, so I guess she'll never "color." Recently I bought a lovely leopard mare. She was bred to an Akhal Teke two times before I got her and both times had a solid foal.  I have been fantasizing about breeding her to a Knabstrupper. If I were to breed her, what color of sire would be my best bet for getting a leopard foal? Is it just a crapshoot pretty much? If I bred to a snowcap would I have a better chance of getting leopard than if I bred to a leopard? Thanks again, Joan

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