Equine coat color genetics can be complicated—all that talk about double-helixes, alleles, loci and more is enough to make your head spin.
But in our ever-increasing world of technology, genetics holds tons of benefits for Paint Horse breeders. By harnessing the power of DNA genetic testing, breeders and owners can gain new insight into their horses and might even be able to boost their color production rates in the quest for the perfect Paint Horse.
A horse has 64 chromosomes and it will always inherit half of those from its sire, and half from its dam—there’s no way around that. But knowing which genes are up for grabs can give you useful tools to predict inheritance possibilities, especially when you’re trying to produce color on top of conformation, athleticism, attitude and other important traits.
The Paint Horse Journal published “The Color Inside,” a two-part genetics education series, in the January and February 2016 issues; a PDF of those two articles is available online at apha.com/breed/geneticeq.
The Pattern Genes
A number of white-spotting genes can influence those beautiful coat patterns that make the Paint Horse breed unique. They include:
- Tobiano (TO)
- Frame Overo (O)
- Sabino 1 (Sb1)
- Splash White 1 (SW1)
- Splash White 2 (SW2)
- Splash White 3 (SW3)
- Dominant White 5 (W5)
- Dominant White 10 (W10)
- Dominant White 20 (W20)
Paints can certainly have more than one of these pattern genes at play—and there are probably others that are yet to be discovered, too—and even though some might look similar, they each have a distinct “address” in the horse’s genetic makeup.
Knowledge is Power
Inheritance for each pattern gene is independent of others the horse might have, and the chances your foal will receive the genotype you want from a parent usually ranges from 25% to 100%. These probabilities depend on the horse’s genetic makeup of that gene (homozygous v. heterozygous v. non-carrier) and the inheritance pattern of the trait (dominant, recessive, additive, etc.).
But when multiple pattern genes are at play between the sire and dam, the likelihood of the foal inheriting at least one increases dramatically … just as your chances of getting “heads” or “tails” in a coin flip improves when more coins are being flipped.
While a horse’s outward appearance—his phenotype—might give you an idea of the pattern genes he has inside, it often doesn’t provide the whole picture. DNA genetic testing is the only way to know exactly what genes your horse has, and that gives you the power to make smarter breeding choices.
APHA offers genetic testing through two partner labs: the University of California–Davis and Etalon Diagnostics. Color & Pattern Panel Testing is available through both—learn more online and order your tests at apha.com/breed/geneticeq.
[Reprinting all or part of this news release is permitted, so long as credit is given to the Paint Horse Journal and a link provided back to apha.com.]
The American Paint Horse Association is the world’s second-largest international equine breed association, registering more than a million horses in 59 nations and territories since it was founded. APHA creates and maintains programs that increase the value of American Paint Horses and enriches members’ experiences with their horses.