Horse Ancestry

Genotyping & Breed Testing

• Ancestry testing is $60 per animal, payable online. There is no testing kit — all we need is 30 to 60 hairs with roots, a filled submission form (download from our Forms page), and an online payment confirmation number. (You will receive an email with this number once payment goes through.)
• Our turnaround time is two weeks once the sample is received in the lab for testing.
• The payment must be online, please click the link on the submission form.

About Horse Ancestry

The modern horse was re-introduced to the Americas by Spanish explorers. The earliest horses to reach North America were of Spanish origin. Although horses from other parts of Europe were subsequently introduced, some New World populations maintain characteristics ascribed to their Spanish heritage.

There are more than 58 million horses in the world, with more than 10 million horses in the USA (FAO 2013 data). It’s difficult to calculate exactly how many horse breeds there are as the Domestic Animal Diversity System lists 1,549 horse breeds, however many countries list the same breeds like Arabian, Thoroughbred, and etc., so that some breeds are counted more than one time. The Department of Animal Sciences – Oklahoma State University maintains a website that lists over 200 breeds alphabetically, and the International Encyclopedia of Horse Breeds by Hendricks (1995; 2007) describes nearly 400 breeds, but estimates there are well over 600.

Throughout the years we have collected and genotyped an extensive number of horse breeds and populations from around the world (see selected publications), however to represent our reference panel for ancestry testing, we selected 50 breeds that are most common for the North America and also represent the major horse groups, such as draft horses, ponies, Oriental and Arabian breed, and Old World and New world Iberian breeds.

Selected breeds are more probable to be the ancestors of current horses in North America and it would be unreasonable for us to use rare or endangered breeds like Waler (Australia), Timor pony (Timor Island), Cheju horse (a southern island of Korea), Namib horse (Africa), Tushuri horse (Georgia), or Pindos (Greece), etc. Also, some North American breeds are not on the list, for example, Appaloosa and American Paint horse, because registries are open, or partially open, and allow crossbreeding. Mustangs are also not on the breed list as it is now primarily a feral horse found in the western United States and managed by Bureau of Land Management (BLM). Originally mustangs were Spanish horses or their descendants, however throughout the years, they had influence from many different horse breeds. There are several mustang registries, but overall, there is just too much complexity to consider them in breed ancestry analysis.

Testing Horse Ancestry in Our Lab

Horse ancestry testing in our lab at Texas A&M is based on comparing the DNA genotype of the subject horse to a reference panel of 50 horse breeds.  Using a computer program based on maximum likelihood analysis, the variants present at each genetic marker system tested for the subject horse are compared to those for each reference breed. For each breed comparison the probability that the subject horse came from that breed is calculated based on the product of all the systems genotype probabilities.

We then report the three breeds with the highest probability that the subject horse could have come from, in order of their probability of being an ancestral breed. The results cannot give the proportion (percent) of the breed that the subject horse may have. That really isn’t possible because horses are so genetically similar. 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 first and second assignments. The more breeds involved in a cross the lower the probability that a good result will be delivered.

Also, understand that even though three breeds are reported, that does not mean the subject horse has all three in its ancestry. Another point is that breeds within a group of related breeds will be given similar probabilities. Thus, the subject horse may be half Belgian draft and half Suffolk, but the test results may show Percheron or even a pony breed. That is because these draft breeds are very similar at the level we can test and the true pony breeds are closely related to the heavy draft breeds.  As well, many breeds have Thoroughbred in their make-up and they will give similar results and will often show similarity to Warmblood breeds.