Interactions of Appaloosa Spotting with Other Genes

Base Color

Pigment Density

Pinto

Shade

Appaloosa Spotting + Black & Red Pigment

Pigment density (i.g., how dark a color is), can alter the expression of Appaloosa Spotting Genes by changing the rate they Varnish, or modifying spot size. On a scale of most dense to least dense, we have Black being the most dense, then Bay, followed by Chestnut being the least dense. With the addition of Darkening Genes, we can modify spot size even on Black coats.

The chart above illustrates how the horses Base Color can influence Varnishing as well as Spot Size. It is important to note that Varnishing and Spot Size are independent of one another. 

Appaloosa Spotting + Darkening Genes

Currently there are two genes that cause Pigment to darken, they are Sooty (Sty and S+) and Dense Pheomelanin (DP). These genes can work individually, or combine together to increase the range of Shade and Spot Size. 

Sooty (Sty and S+): Darkens a horses coat, and can also increase Spot Size, even in Black Based horses. Sooty + also darkens the coat, but breaks up the pigment to produce heavy dappling. 

Dense Pheomelanin (DP): Increases the production of Red Pigment, and can also increase Spot Size, even in Black Based horses.

The chart above illustrates how the horses Base Color and Darkening Genes can influence Spot Size. It is important to note that these Genes work on Black Based horses as well, even if they are not visually seen. 

Sooty Plus (S+) and Spot Size

All three horses above are LP/-, PATN1/-, S+/S+. While Sooty + changes the shade of a horse, it can also creates larger Spots. 

Appaloosa Spotting + Pigment Density Regulator (Bl)

Currently Pigment Density Regulator (Bl) does three different things in the game:

1. Reduces the amount of White from Pinto Related Genes
2. Adds freckling to White Pinto Related Patterns
3. Deepens the Red in the Base Color

Of these three things, the only one that affects Appaloosa Genes is the deepening of Red. It is a very minor change, unlike Sooty and Dense Pheomelanin.

Pigment Density Regulator (Bl) changed the Shade of the Chestnut horse with each copy of Bl. Because it was Darkening the coat, the effect of Varnishing was also reduced (more Varnishing with no Bl).

Check out Study #4: Appaloosa Spotting + Pigment Density Regulator (Bl) to see more examples of Pigment Density Regulator and Darkening Genes.

Appaloosa Spotting + Lightening Genes

Cream/Pearl/Sun/Sno
Dun/Non-Dun
Champagne
Silver
Mushroom

Appaloosa Spotting + Pigment Removal

Grey

Appaloosa Spotting + Other Genes

Flaxen
Pangare

Appaloosa Varnishing will have different expressions between Mares and Stallions, with Mares varnishing a little faster than Stallions.