Pet DNA Services of AZ - Equine DNA Testing

Here are some of the most commonly asked questions
we receive regarding our Equine DNA testing services.
Feel free to Email Us if your question is not answered here.

Question 1
How long have you been offering DNA testing services?
Pet DNA Services of AZ was officially established in August 2004. Although we are relatively new, our Director's long record of successful research work in DNA testing and analysis (see Credentials) is a foundation which guarantees top quality services accompanied by thorough, expert interpretation of the test results.

Question 2
Do you test for homozygosity?
This question is typically being asked in connection with the Tobiano or the Black/Red Factor test. The answer is yes - all of the DNA tests we offer provide information whether the horse is homozygous or heterozygous at the tested gene. In case s/he is homozygous, we can tell you which of the alternative forms of the gene (alleles) the horse is homozygous for.

Question 3
Do I need to send a separate hair sample from the same horse for each test I am requesting?
No. We only need one pulled hair sample (about 20-30 strands) to perform all tests we offer.

Question 4
I have been told that a horse homozygous for Tobiano cannot be a carrier of the Lethal White Overo/OLWS gene. Is it true?
This is not true, and completely misleading. The white spotting genes causing Tobiano and OLWS are independent from each other, and can be found combined in the same horse. This also includes the possibility of having a Tobiano homozygote horse carrying the OLWS gene. The OLWS gene occurs in many breeds, and is not always manifested in the carrier's phenotype (meaning, you often cannot tell visually just by looking at the horse, if it is a carrier). Please note that even "solid" (breeding stock) paints, tobianos/toveros, Quarter Horses, and others can and do test positive for this gene on occasion. If unsure, we strongly suggest you have your horse tested for LWO/OLWS, before breeding.

Question 5
For how long is the pulled hair useful for DNA testing?
In our experience, the hair can be used for several months after it is collected. Just please make sure to keep it dry.

Question 6
What is the purpose for DNA testing of coat color genes?
The information gained from DNA testing of coat color genes is useful in several ways. It can help to define/verify the base color of a horse (particularly if obscured by other genes such as Grey, double Cream Dilution), and to determine the possibility whether a horse can (or cannot) produce certain color(s) in the foals. Based on the DNA test results, the owner has the opportunity to make an educated decision with what mate to breed the horse to increase the probability of getting offspring with a desired color. A special case is testing for the Lethal White Overo gene (LWO/OLWS) to detect carriers of this mutation. Because the mating between two LWO/OLWS carriers has a 25% calculated risk of producing a lethal white foal, conscientious testing for LWO/OLWS is important to minimize/prevent such unfortunate events.

Question 7
Can DNA testing be used to determine the breed of a horse?
Although DNA testing is used to reliably distinguish between individual horses, and for example verify parentage, it is not possible with today's DNA technology to determine the breed of a horse, or to distiguish between different breeds.

Question 8
What is the youngest age at which a foal can be reliably tested?
A reliable DNA testing can be performed at any age, starting with a newborn foal. However, we need pulled tail hair from such young foals.

Question 9
Is there a DNA test yet for Roan (or Champagne, or Grey)? If not, how soon it may become available?
So far there are no commercial tests offered for any of these genes. Although it is known that studies are underway to identify these genes, there is no further information available when the actual tests may become offered to the public.

Question 10
Do I have to request your kit to get my horse tested?
No. You can send us the hair sample in a labeled ziplock bag or envelope, together with the printable test request form, which is available at our website. If you cannot print the form, just include a sheet containing inromation about the horse (breed, sex, color, name, registration # if available), and your contact information. However, if you prefer to use our kit, we will be happy to send it to you. Just email or call us. There is no charge for the kit.

Question 11
Does my horse have to be registered to be tested in your lab?
No.

Question 12
What ID information do you need to issue a certificate for an unregistered horse (or if registration is pending)?
Breed, DOB, and - if available - the name and registration numbers of the sire and dam.

Question 13
Why do I have to provide a picture of the horse I want to have tested?
Although we appreciate it if a picture is available, it is not a requirement. However, the interpretation of color test results is sometime more accurate and effective if we have a photo. You don't have to send us a printed photo - just email it, or provide a link to your website.

Question 14
If you breed two solid horses together that were both produced by Tobiano parents, can their foal be either Tobiano or solid?
Two true solid horses cannot produce a Tobiano foal, only a solid one. It doesn't matter if the solids are out of two Tobiano parents - they did not inherit the gene. PS: If two Tobiano parents produce a solid offspring, neither of the parents can be homozygous for Tobiano.

Question 15
What does the word "Agouti" mean?
Agouti is a rodent living in South America, which has a typical hair color pattern that is also found in many other animals (mice, rats, rabbits etc). The hair has dark and light banding, which is controlled by a gene that has been named Agouti. This gene modifies where the black pigment shows up. In the mice, for example, it gets switched on/off during hair growth, and therefore the so called grey (wild-type) mice have a part of the hair that contains the yellow/brown pigment (Agouti is on), which alternates with black (Agouti off). This gene is found in all mammals. There are two confirmed variants of this same gene in horses (A, and a), which are responsible for the difference between bay (black hair only in the mane, tail, and legs), and solid black color.

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