Recent breakthroughs in colour genetics

Barlink Gold Rush (Barlink Macho Man x Barkota Bell), Paint stallion

The “Barlink” dilution (so called because it is found in horses descended from the Paint stallion Barlink Macho Man) resembles the effects of both the champagne gene and the “Pearl” dilution (which I mentioned in an earlier post):

In single dose, the Barlink factor appears to dilute the skin of the carriers. The chestnuts with submitted photographs have pink speckles on their otherwise black skin, very similar to what happens on many cream dilutes. The gene is not cream, as these mares do not demonstrate the cream gene when tested by UC Davis. With a single Barlink gene, the coat color does not seem to be affected.

In double dose, the Barlink factor appears to dilute the hair coat to a medium dilute shade (similar to one cream or one champagne gene), and dilutes the skin to near pink.

The Barlink factor appears to enhance cream, essentially causing a double dilution of the hair coat, skin and eyes. This would cause the phenomenon of pseudo-cremello and pseudo-smoky cream foals. I have not yet seen the effect on buckskin, but it is likely a pseudo-perlino would result. (Link)

The brilliant folks at UC Davis have recently announced that they have come up with a genetic test for the Barlink dilution, which they are calling “apricot”. The tests are done using mane or tail hair with the roots attached.

Update (Oct 22/06): UC Davis is now calling this dilution “pearl”. It’s been found to be the same gene, and most likely came to the Paint/QH gene pool through the breeds’ Spanish ancestry. Lovely how everything comes full circle. 🙂

Wilson’s Smoky Jo, black silver dapple Missouri Foxtrotter stallion

The gorgeous silver dapple gene (which the Aussies call ‘taffy’) dilutes black pigment: on a black horse, the body colour becomes a silver or chocolate colour, with the mane and tail turning silvery. On bay, brown or buckskin horses, the manes, tails and leg points are diluted while the body usually stays red or tan, depending on the base colour. A new study has just been published identifying the gene responsible; a test for silver dapple can’t be far behind. So far, the colour has been identified in the following breeds: Shetlands, Welsh Ponies, mustangs, Miniature Horses, Icelandics, Missouri Foxtrotters, Tennessee Walkers, Rocky Mountain Horses, Quarter Horses and Morgans (but may be in other breeds as well). Speaking of Morgans, Laura Behning has done a lot of research into the silver dapple gene in Morgans (and bred a corker of a bay silver dapple colt this year): The Silver Dapple Morgans Project.