Ten years ago I wrote an article entitled “A Study of White Horses – Not What They Seem”, where I questioned the existence of Dominant White in horses. My skepticism was based on my own research into the backgrounds of as many white-born horses as I could find. From that I came to believe that most of the horses designated as Dominant White were more likely to be extremely marked sabinos. I failed to find horses that fit the profile for Dominant White, so I began to suspect that the color did not exist – or perhaps no longer existed since there were anecdotal stories of horses that had fit the profile in times past.
It appears that my speculation was wrong, at least in terms of whether or not there was such a gene in horses. Not only are there real, live Dominant Whites, but the Swiss team that identified them has been able to test for it. So eventually we will know for sure which horses carry the gene. (It is thought that the gene is extremely rare, so it is likely that many of the white-born horses are still just sabinos.)
Other things are in the works, too. A Swedish team found the mutation for grey, though a test is not yet available. UC Davis has been working on dun, and of course there is the ongoing research on the appaloosa patterns. Pretty soon there won’t be anything left to guess about when it comes to horse colors!
(pictured is the famous white Thoroughbred, Mont Blanc II.)