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Study #3: Appaloosa Spot Regulator (ASR1)

This study looks at how ASR1 is influenced by other genes. 

Study #3: 1yo Bay Appaloosa

E/e, A/A, LP/-, PATN1/-, ASR1/ASR1

Removing ASR1 Genes


Bay LP/-, PATN1/-, ASR1/-


Bay LP/-, PATN1/-


ASR1 is an incomplete dominate gene, and will have a stronger effect on the spots when Homozygous

Adding Sooty (Sty) + Removing ASR1 Genes


Bay LP/-, PATN1/-, ASR1/ASR1, Sty/-


Bay LP/-, PATN1/-, ASR1/ASR1, Sty/Sty



Bay LP/-, PATN1/-, ASR1/-, Sty/Sty


Bay LP/-, PATN1/-, Sty/Sty

Notice how the addition of Sooty causes the spots to spread further apart. Referring back to the original horse, you can see their spots are very close together, even overlapping. When Sooty is added, the Spots spread further apart, giving the distinct impression of larger spots. 

Adding Dense Pheomelanin (DP) + Sooty (Sty)


Bay LP/-, PATN1/-, ASR1/ASR1, DP/-


Bay LP/-, PATN1/-, ASR1/ASR1, DP/DP



Bay LP/-, PATN1/-, ASR1/ASR1, DP/DP, Sty/-


Bay LP/-, PATN1/-, ASR1/ASR1, DP/DP, Sty/Sty

Darkening genes don't add to the Spot Size, but they do make the spots spread further apart. 

Adding Diluting Genes to Appaloosa Spot Regulator (ASR1)


Bay LP/-, PATN1/-, ASR1/ASR1


Palomino LP/-, PATN1/-, ASR1/ASR1

Reducing the pigment concentration through use of Dilution genes makes minute changes to the white pattern. In the case of Bay vs Palomino, the Palomino has lost some of the smaller freckled spots on their Blanket, giving the impression of larger white areas. 

Final Observations

  1. In the presence of Homozygous ASR1, adding and removing pigment doesn't appear to change Spot Size. It does however influence Spot Spread.