¶ Leopard Complex
¶ Overview
Achieving leopard complex coloration involves multiple genes (polygenic), many of which are currently unknown and untestable. Determining what their pattern is can be broken down into a multi-step process though, which you can read about below.
¶ Step 1: The 'On/Off Switch'
¶ The Leopard gene (aka TRPM1)
The first and most important gene for leopard complex coloration is actually testable, and is the ‘Leopard’ gene in your horses' Pattern Genetics tests. This gene is often called the ‘on/off’ switch for leopard complex patterning:
If a horse has at least one Lp allele (Lp/n or Lp/Lp), then they are ‘on’, meaning leopard complex coloring is possible (not guaranteed, keep reading). If they do not have an Lp allele (n/n), then they are ‘off’, and cannot have leopard complex patterning.
¶ Step 2: White
¶ The PATN genes
The Leopard allele alone will give a horse some subtle coloration: mottled skin (would be seen under the hair), a white sclera (part of the eye), and sometimes striped hooves too. But, that's all this one allele does on its own. To get the characteristic white patterns with spots, you will also need PATN alleles.
What are PATN genes? Well, PATN is simply an abbreviation for ‘pattern’, and basically these genes increase or decrease the amount of white expressed on a Lp/- horse. Only one PATN gene, called PATN1, has been identified, and it is testable. But, not every horse with leopard complex white patterns has PATN1, so we know there are other genes out there, they just haven't been identified yet.
What about Legacy, since the genes are unknown, how does the game work? We have simulated 10 PATN genes (including PATN1) in the game. These 10 genes work synergistically to determine how much white a Lp/- horse will have. In fact, there are 8 ‘levels’ of leopard complex white in Legacy, and you can breed for as much or as little white as you want! Coats will range from a ‘solid’ leopard complex horse (who only has the mottle skin, white sclera and striped hooves), to snowflakes, to blankets/snowcaps, to full-body leopards/fewspots. Here are a few examples:
One more thing, without Lp, the PATN alleles don't make white. So, if you have a leopard n/n horse with PATN1, they will not have leopard complex patterning.
¶ Step 3: Back to the Leopard Gene
Okay, so now that you understand how Lp is the ‘on’ switch and PATNs make white, there is one more thing you should know about the Leopard gene. It is actually incomplete dominant, meaning a heterozygous Lp/n horse is usually distinguishable from a homozygous Lp/Lp.
We point out usually because, if a horse has very little PATN white (they are solid or snowflake patterns), then you won't be able to see a difference between a heterozygous and homozygous horse. But, if the horse has enough white that they have spots (at least a blanket), then you will see that a homozygous Lp/Lp horse will have much smaller and fewer spots than a heterozygous Lp/n horse. Actually, some Lp/Lp horses won't have spots at all, but will still have white.
Distinguishing homozygous vs. heterozygous Lp is important because it actually changes the name of the horse's pattern (unless they are solid or snowflake, those stay the same). With Lp/Lp, a blanket is instead called ‘snowcap’, and a leopard is instead called ‘fewspot’.
Here are some examples:
¶ Step 4: Other modifiers
Leopard complex patterns vary a lot between horses in real life, so we also added several extra genes into Legacy to try to simulate this variety. For example, some horses have ‘varnishing’, a unique roaning, while others don't. That's just one of the extras we added though, but that's also all we will say about them! Have fun trying to discover them all.
