The Interaction Between LP and PATN1 Genes

As awareness of genetic testing grows and more breeders embrace it, we gain a deeper understanding of what’s really behind our horses' coat.

Yet making sense of all the technical terms, how different genes interact with each other, and knowing what to do with that information isn’t straightforward. But, I think it’s the challenge of these complexities that gets breeders hooked!

The possibilities. The curiosity. The individuality.

Although sometimes it feels like the more we learn about the genetics behind the extraordinary Appaloosa, the more questions we have. Let's see if we can unpack some of the basics…

Firstly, every horse (and living being) inherits two copies of each gene – one from each parent. This is why genetic results show two notations (like lp/LP or n/PATN1). These paired copies determine which traits appear. Understanding this is key to making sense of all the combinations that follow.

The Leopard Complex (LP) Gene

I recently read an article that explained the Leopard Complex gene (LP) as the torch illuminating the PATN1 gene to bring out Appaloosa spotting patterns. To unlock the full range of spotting possibilities LP requires PATN1 as a genetic partner. As a dominant gene with incomplete dominance, the number of LP copies a horse inherits directly affects white patterning – one copy allows for variable patterns, while two copies typically produce more extensive white markings.

LP Gene Results

• n/n = Negative

This horse does not carry the LP gene and will not show leopard spots.

• n/LP or lp/LP* = Heterozygous

This horse has one copy of the LP gene, allowing for a wide variety of patterns (leopards, blankets, frosting, or roaning). They will pass the LP gene to approximately 50% of their foals.

• LP/LP = Homozygous

This horse has two copies of the LP gene and tends to have much more white on their body, such as fewspots or snowcaps. They will pass the LP gene to 100% of their foals.

Regardless of coat pattern, all horses carrying the LP gene will exhibit the characteristic Appaloosa traits – mottled skin, white sclera and striped hooves.

*Note: In NZ when there is only 1 copy of LP, the negative copy is often represented as a ‘little lp’ which is the same as ‘n or N’ used in American terms. Just to confuse us further.

The PATN1 Gene

If we imagine that LP is the torch switch for spotting, PATN1 acts as the brightness dial. When a horse carries both the LP gene and PATN1, it produces larger, louder white patterns – typically 60% or more of the body – such as spotted blankets, full leopards, or fewspots.

If a horse carries PATN1 but no LP gene, the PATN1 has no visible effect on coat colour. The horse is a genetic carrier for spots but won't display them itself. This is an important distinction – PATN1's role only activates in the presence of the LP gene.

Putting It Together: What the Combinations Mean

Here's a quick guide to understand what different genetic combinations produce:

• n/n LP with n/PATN1

Solid coloured horse, but if bred to an LP carrier, offspring can show a surprising amount of white if they inherit the PATN1 gene.

• lp/LP or LP/LP without PATN1

Generally displays white blankets or roan like markings with less dramatic patterning.

• lp/LP with n/PATN1

Shows spotting patterns with an unusually high amount of white – often 60% or more of the body at birth.

• LP/LP with n/PATN1

Produces snowcaps and fewspots.

• lp/LP or LP/LP with PATN1/PATN1 (two copies)

Has the greatest chance of throwing leopards, snowcaps, and fewspots. When bred to a horse carrying two copies of PATN1, this maximises the odds of spotted foals.

How This Helps

Each parent contributes one copy of each gene – LP and PATN1 – to their foal, so breeding outcomes depend on what both parents carry and pass down.

When considering breeding, whether you're a mare owner looking for the right stallion or a stallion owner wanting to make informed decisions, knowing both their LP and PATN1 status gives you crucial information about what you're working with and improves your odds of achieving the results you want in the next generation - whether you’re aiming for colour or otherwise.

What we see on the exterior doesn't give us the full picture. A beautiful spotted horse might carry genetics that surprise us in the next generation – or a seemingly solid coloured horse might be hiding incredible potential underneath. You can't always judge a book by its cover, and with horses, you certainly can't judge their genetic potential by appearance alone.

Of course, as with all genetics, nothing is set in stone. Variations do occur, and nature always has surprises!

Dianne Udy - Councilor

To get your horse tested or find out more get in touch with InfogeneNZ

If you've never collected hair samples for testing before, check out this video from UC Davis Veterinary Genetics Laboratory >>>How to collect hair samples