How to Read Horse DNA Results
Learn how to read the results from your horse's DNA test. Please note - this is in reference to results only from DNA My Horse. DNA My Horse uses our own bio-algorithm to interpret your horse's breed results unlike other tests on the market that strictly tell you your horse's ancestry over the course of 1000 generations.
The test results cannot give the proportion (percent) of the breed that the subject horse may have; that isn’t possible because horses are a combination of many different breeds. The test is reasonably good but there is no way to determine how accurate it is. If a purebred horse is tested it will almost always be assigned to the correct breed. When a two breed cross is examined, the two parental breeds will almost certainly be given very high probabilities although not necessarily the 1st and 2nd assignments. The more breeds involved in a cross the lower the probability that a good result will be delivered.
Another point is that breeds within a group of related breeds will be given similar probabilities. Thus, the subject horse may be purebred Paint but the test results may show Quarter Horse. Or a QH is actually a Quarter Pony due to size. This is because these stock breeds are very similar at the level we can test at. True pony breeds are also closely related to the heavy draft breeds. Many breeds have Thoroughbred in their make-up so a horse may test as part Thoroughbred but actually be a purebred Quarter Horse as many QH's have a lot of TB blood (again from the DNA's point of view). Many gaited breeds are genetically similar to other gaited breeds so a TWH may actually be a MFT depending on the genes actually expressed. Remember breeds are a human construct; many breeds being only recently created. Also, a horse that is part gaited may not actually be "gaited" due to extra gaits being a recessive gene (meaning the extra gaits are not always passed down if a horse is part gaited).
We test for genetic markers unique to each horse breed. Many breeds share these genetic traits together which means some tested horses may show closer affinity to a related breed than to the one it actually comes from. A horse's DNA is carried down generation to generation with some markers that get passed on. It is not possible to identify the generation the markers come from. We report the likelihood of the horse being from the breed identified based on the markers present, whether recent or in the horse's past.