I love seeing all the ideas that come in for our mystery coloured horses! This time most of you went the same way as me and thought it might be some sort of splashed white gene. It’s not!
This stallion is Coralvale Playboy (https://www.facebook.com/PHAAstallion/). He is a buckskin with … wait for it … the sabino 1 gene.
We tested him for the following genes:
Both base coat colour genes (agouti and red/black)
Two dilutions (cream and dun)
Five common white patterns (frame overo, SW1, SW2, W20 and sabino 1)
The results were as follows:
Agouti (ASIP gene): A A (two copies bay factor)
Red/black (MC1R gene): E e (one copy black, one copy red)
Cream (SLC45A2 gene): Cr n (positive for cream, one copy)
Dun and d1 (TBX3 gene): n n (negative for dun and d1)
So far this tell us that he is buckskin with no dun and will never produce black or smokey black foals. I’ll talk about the iridescent coat at this point too: it is not something we can test for, and it’s definitely not pearl. Buckskin pearls are a completely different and unique colour, with peachy skin, light eyes and a lighter coat than a buckskin (do a search for MP A Moment In Time to see a buckskin pearl here in Australia). Iridescence on a normal coat colour is something different. Maybe one day we will be able to test for it, but not yet.
The rest of the results were:
OLWS or frame overo (EDNRB gene): n n (negative for OLWS/frame overo)
Sabino 1 (KIT gene): SB1 n (positive for sabino 1, one copy)
Splashed white 1 (MITF gene): n n (negative for splashed white 1)
Splashed white 2 (PAX3 gene): n n (negative for splashed white 2)
W20 (KIT gene): n n (negative for W20)
So there you go – the only thing that tested positive was sabino 1. It’s fascinating to see how different his sabino 1 markings look to most sabino 1 paint horses. Where’s the usual roaning? Why do his markings have such clean edges and why are they smaller than usual? We don’t know the answers to any of these questions yet – there is still so much to learn in horse genetics.
Despite his atypical markings Coralvale Playboy has gone on to produce foals horses with the markings we usually see with sabino 1 (yes Melita Gard I can see why you guessed it was sabino 1!), as well as patterns like medicine hat markings that are standard fare for horses with sabino 1 plus other white marking genes.