The LP Complex

I have some questions about the LP genes.

1) When crossed with solid colored horses who do not carry the LP gene will you still get spots?

2) What is the most dominant LP gene? I think I read that varnish roan was incomplete dominance... What exactly does that mean? And is this true for all the separate LP patterns? Like blankets, roans, leopards, few spot, ect...

3) Is there any way to determine what pattern a foal will get or is it just kind of an act of God so to speak?

I think that's all for now. Thanks in advanced!

I am not an expert but I love Appaloosas!

When a horse is LpLp, they carry one copy of the gene and can pass it on. The foal could be a solid or have a pattern but even if a solid, it would still carry a copy of the gene and produce a foal with spots when bred to another horse that also carries it.

LPLP are homozygous for it and will produce a pattern 100% of them time. These horses will also suffer from congenital stationary night blindness.

Anyone better than me feel free to correct me if I'm wrong.

EDIT: From what I've been reading and hearing in the Appy community, the snowcap pattern tends to produce colored foals most of the time. I have no clue if snowcaps are LpLp or LPLP.

I've always wondered if the different types of patterns were the results of different genes but I've never asked nor researched that completely. No test exists yet to test for them anyway as far as I know.

EDIT II: Also I understand that few spots are very desirable because they tend to be high color producers.

Appaloosa LP and CSNB Testing

I'll answer what I can as best I can...

A colored/spotted Appy will throw color/spots on 25% of foals when crossed with a solid horse if the Appy is heterozygous, and 100% of the foals if it is homozygous (true fewspot or true snowcap).

I am not sure there is a "dominant" LP gene. We still do not know everything there is about Appy genetics and exactly why some are blankets, some are varnish roans, and why some have more than one pattern.

Normally there is no way to determine what pattern (if any) a foal will have, other than it will have something if one of its parents is homozygous. However, there are lines and combinations of lines that do produce a high incidence of leopards, and their are some lines and combination of lines that very rarely produce a solid foal. As we continue to discover more about Appy genetics, more and more of the answers will become clear...


ETA...Just a short opinion-editorial - Horses should not be bred only for color, so a fewspot should not be any more desireable as breeding stock than any other pattern. Horses should be bred for ability - not color. Sorry for the op-ed...the devil made me do it...

Incomplete dominance means a single gene will produce a certain effect, while carrying both genes will cause a different effect. That's about as basic as I can figure out how to explain it. Cream is an incomplete dominant. Crcr will give you palomino, buckskin, and smoky black. CrCr will give you cremello, perlino, and smoky cream.

I'm awful at how Appy genes actually work, I just know how to determine the pattern of them.

If the appy color is dominant, defined as that the color will show whether the horse is homozygous or heterozygous, and it is bred to a solid horse, which would not carry the gene, then how do you get the 25% rather than 50% if the appy horse is heterozygous? Would it not have a 50/50 chance of producing a foal with the appy trait?

Am I missing something?

Is there anyway to tell if a horse is homozygous or heterozygous without testing? Or do you always have to test? I have a mare that shows a blanket with some spots and varnish roan, are those indicators of homo or hetero?

Face- I don't plan on breeding for color, but if I do want to breed it's nice to know whats going on genetically. I know that tempermant and conformation trump color. Appy's are my breed of choice so it's nice to know about their different pattern traits.

(recessive/non-existent alleles will be "n" for extra clarity)
Let's say a stallion is heterozygous for whatever pattern, nLP.
The mare is solid, doesn't carry any appaloosa pattern, nn.

---- n -- LP
N -- nn - nLP
N -- nn - nLP

So yes, there's a 50/50 chance with a heterozygous leopard and a non-leopard. Now, if it were two heterozygous leopards...

---- n -- LP
N -- nn - nLP
LP - nLP - LPLP

Then we get the 25% for both non-leopard and homozygous leopard and still 50% for heterozygous leopard.

So yes, you're correct...though I don't think we can really place a completely accurate number on what a foal will be...it's not like literally one out of four foals will be non-leopard and everything...XD

From what I have read (there's a good article I am trying to find for you, I'll post if I find it), Lp is an incompletely dominant gene. (Appaloosa Genetics: Part I | Appaloosa Journal)

As far as we know there is only ONE gene that causes appaloosa characteristics -- The Lp gene -- it's kinda confusing because obviously not every appaloosa is a leopard, however, all appaloosas when combined with a specific mate CAN produce a leopard.

So, as much as I hate the term, a "varnish" roan, looks the way it does as a result of the Lp gene. There are no other genes involved, that people know of yet, to cause such a phenotype.

As Faceman said, yes, there are ways to tell if a horse is homo/heter w/out testing.

A few spot (nearly "white") is considered homozygous as well as a TRUE snowcap.

FOUND IT!!!

Appaloosa Colour Pattern Transmission

Yall have been very helpful!

I found one of this studs foals for sale on Craigslist and I just think he is gorgeous.
He is a snowcap correct? Is there something else at play causing his spottiness in the other areas?