DNA Tests Answer Certain Questions
DNA testing of horses has become increasingly common in recent years, but some degree of mystery and misunderstanding still surrounds the process. A better understanding of DNA testing illustrates how invalu- able the testing can be, while at the same time it still has its limitations.
The History UC Davis Veterinary Genetics Laboratory (VGL) in North- ern California was a pioneer in the use of DNA to verify the parentage of horses. They were the first to offer DNA test- ing of horses and cattle in the mid-1990s. Today they offer DNA testing for 17 animal species. Equine DNA testing has become increasingly common and tests have been added to cover a variety of things from color testing to the heritability of certain diseases. Horse registries have also begun to increasingly utilize
DNA testing as a requirement for registration or for the approval of breeding stock. Most internationally recognized Warmblood and sport horse registries now require at least some degree of DNA testing as a part of the registration and/or breeding approval process.
Testing Your Horse DNA testing is done using a sample of hairs from the mane or tail of the horse. Usually 20–30 hairs are required. The hairs must be pulled (and not cut) so that the root bulb is attached. Generally, the hair sample is pulled from the mane, but for foals it may be necessary to pull the hair sample from the tail. The person collecting the hair sample should have clean hands and should be careful not to touch the roots of the hair, as this could contaminate the sample. Care should also be taken to keep all samples completely separate from each other. The hair sample is then submitted either to a
Warmbloods Today 59
By Gigha Steinman
horse registry or directly to the lab, usually taped to a piece of paper. It is usually recommended not to submit hair samples in plastic bags as bacteria is more likely to grow on the sample, which could make testing more difficult or impossible.
The Basics The laboratory will use the hair sample to extract DNA from the hair follicle cells. This DNA will then be used to identify “microsatellites” or pairs of DNA markers. A unique “DNA Marker Report” is then generated for the horse. The two most prominent labs in the United States for equine DNA testing are UC Davis Veterinary Genetics Laboratory (VGL) and the University of Kentucky (UK). VGL uses fifteen micro- satellite markers to generate an equine DNA marker report, and UK uses thirteen.
An example of a DNA Marker Report provided by the author.
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