DNA Required Testing
DNA testing through the USAHR approved laboratory, using the provided DNA kit, is required for all foal registrations. Additionally, all stallions and mares who are to be used for breeding will be required to have a second DNA test which must match the DNA results on record.
DNA Testing for Genetic Lethals
TESTING FOR CEREBELLARA ABIOTROPHY [CA], LAVENDER FOAL SYNDROME [LFS], AND SEVERE COMBINED IMMUNODEFICIENCY [SCIDS] IS REQUIRED FOR ALL BREEDING STALLIONS AT THIS TIME. If said breeding stallion has been tested, the owner can request the testing laboratory to submit copies of these tests to the Registry office for inclusion with the stallions file, otherwise testing must be done with reports submitted from the approved laboratory to the US Arabian Horse Registry office. For more information on these required tests contact Vet-Gen, 3728 Plaza Drive, Suite 1, Ann Arbor, Michigan 48108 or visit their website www.vetgen.com
Breeding mares will be “grandfathered” into this required testing for genetic diseases.
HORSE ANCESTRY TESTING
Horse ancestry testing at Texas A&M University is based upon comparing the DNA genotype of the subject horse to a reference panel of 50 horse breeds. Using a computer program based upon 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 upon 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 the breed 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 1st and 2nd 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.
Read more at their website http://vetmed.tamu.edu/animalgenetics/horse-ancestry
Our laboratory is an Institutional member of the International Society for Animal Genetics (ISAG). We participate in ISAG comparison tests and report DNA types according to standardized nomenclature. Our most recent certificate of participation. ISAG institutional member number 105247.
Two reports will be submitted.
Horse genotyping report – DNA type (aka DNA profile, aka DNA fingerprint). DNA type shows the markers used (microsatellites – VHL20; HTG10 and etc.) with allele sizes for the markers coded in letters (VHL20 – PR; HTG10 – LR; AHT5 – KN and etc.). DNA types are reported according to standardized nomenclature of ISAG. If one of the parents or both parents are available, parentage verification will be performed and it will reflect on the report (sire/dam qualification/exclusion).
The horse ancestry report with breed assignments is the second report. There is no provision to provide percentages.
Does this answer your questions? If not, please contact the Registry office for assistance.