Though DNA testing are often used to determine parentage and lineages in humans, they may also be utilized in animals.
A horse DNA test can assist in determining paternity. Owners and breeders may wish to know which horses in their herd gave birth to the foal.
Breeders may even be required to verify the genetics of a stallion or mare that will be used for breeding.
A comprehensive reference on DNA testing for horses can help you grasp the significance, method, and other important aspects.
In this article you will learn more about five-panel genetic testing and how it may help with breeding decisions. You will also learn about some background info about horse dna testing, horse genetics for beginners and the benefits of dna testing your horse.
- 1 How genetic testing for horses began
- 2 The 7 color genes that reveal a lot about your horse.
- 3 The Benefits of DNA Testing in Horses
- 4 How Reliable Are Horse DNA Tests?
- 5 Explanation of Horse DNA Testing Results
- 6 The Five-Panel Genetic Examination
- 7 Horse Genetics for Beginners
- 8 How Do DNA Tests for Horses Work
- 9 How to Extract Horse Hair for DNA Testing
- 10 Horse Genetic Testing Options
- 11 Is it true that every horse has a unique DNA profile?
How genetic testing for horses began
A mystery illness ROCKED the Quarter Horse world, as well as breeds bred with Quarter Horses, in the late 1980s. Horses with muscular tremors, weakness, collapse, and even death made news after the reason was linked to a hereditary illness passed down via a renowned Quarter Horse lineage. When experts reported that HYPP (hyperkalemic periodic paralysis) was connected to a well-known stallion called Impressive, breeding barns across the country erupted.
A decade later, breeders began to recognize the need of limiting the spread of this lethal illness. The American Quarter Horse Association passed a regulation in 1998 that required all foals descended from Impressive to be tested for HYPP and have the findings mentioned on their registration papers. Horses with two genes for this illness were no longer allowed for registration in 2007. This marked the start of genetic testing and the AQHA’s attempts to reduce the spread of hereditary disorders within the breed.
What You Can Learn from a DNA Test for Horses
A horse DNA test may teach you a lot. If you just want to know which horse sired your foal, you may easily find out by submitting a DNA sample from the foal, sire, and mother. The findings will be compared to see if your stallion is indeed the father of that young horse. A horse’s probable ancestors’ DNA can also be discovered. Typically, the findings will offer you up to three potential breeds that are part of your horse’s heritage.
Texas A&M University administers this exam. The information is possible because of the genome project and the 50 most prevalent breeds examined across North America. If you want to know if your horse has the speed gene 2, for example, before you decide to utilize your horse for racing, you may find out. DNA testing can also be used to discover the seven color genes. If you want to have a comprehensive DNA profile performed rather than simply parentage or ancestry, all genes of the horse are analyzed and identified during testing.
The 7 color genes that reveal a lot about your horse.
Gene W
This gene signifies a horse that is unable to produce pigment.
The horse’s skin and mane may be born extremely pale in hue. This is frequently mistaken for an albino horse, although it is actually a white horse.
Gene E
This gene denotes the pigmentation of black hair. If the horse’s complete body, as well as its mane, is black, it may carry this gene.
Gene G
Is similar, however the horse’s color will not be as light 3. This gene is frequently seen in white horses. They are not albinos since their skin still has color. Their hair is the only thing that lacks pigmentation.
Gene A
Is responsible for the dispersion of black pigmented hair. The horse may have some black hair, such as the mane, but the remainder of the animal will be another color, such as brown.
A pigment dilution is included in Gene C. For example, a horse’s red pigment may be diluted to more of a yellow color hue.
Gene D and Gene TO
These are now are the remaining two possibilities. Gene D produces pigment dilution and a dun pattern. A horse’s coat may be splotchy. There may be regions of one color with dots of another, lighter hue.
A horse with the Gene TO spotting pattern has a Tobiano spotting pattern. These patches are white in color and are more easier to identify as spots than horses with the Gene D.
Because most horses have some variant of these genes, a comprehensive DNA workup is required to look at all gene types.
The Benefits of DNA Testing in Horses
A DNA test not only reveals the father of the foal in question, but it also offers an identification number for your horse.
If one of your herd was ever lost or stolen, you’d have a DNA profile to prove the horse is yours. A profile obtained from the horse you suspect is your lost or stolen prize might then be compared to see if he or she actually belongs to you.
Another significant advantage of DNA testing is medical information. This is especially true if you have a five-panel test performed. You’ll be able to identify the underlying medical issues your horse has that might be passed on to its progeny.
It enables breeders to choose which horses to breed and which to avoid. It also allows you to take preventative actions to assist your herd stay healthy 4.
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How Reliable Are Horse DNA Tests?
DNA testing for horses, like DNA tests for humans, are never completely accurate. They do, however, provide a high level of accuracy as long as the horse is not a mixed breed. Because of improved technology and an availability of knowledge on DNA and genetic profiles of many horse breeds, many facilities that currently do these tests promise a 99.9 percent accuracy.
However, it appears to be more difficult to identify the findings for a mixed breed horse than it is for a purebred horse. Because the horse family does not have as many breeds as the dog family, these tests are generally more precise than dog DNA testing.
They have also stayed quite pure in their lineages and have not been heavily mixed.
Explanation of Horse DNA Testing Results
The results displayed will differ based on the type of testing you conducted.
If you send in hairs for a basic DNA test to identify paternity, the findings should show a relationship between the sire (father), dam (mother), and foal (child).
A normal genotyping DNA test will include a list of genetic markers. VHL20, HTG4, and ASB2 are only a handful of the possible markers. Each of them will have a unique number assigned to it. This reveals the horse’s genetic composition and aids in the determination of a variety of aspects, ranging from color to the possibility of carrying certain diseases to other distinguishing features observed both physically and behaviorally with the horse.
In several areas, a foal’s statistics are frequently identical to those of one of its parents.
The Five-Panel Genetic Examination
Five panels are required for a test to assess stallions’ reproductive potential. This five-panel test can be used in conjunction with the AQHA’s standard DNA test (see video). Futher down you can read more about GBED, HERDA, HYPP, MH, and PSSM. To the layperson these acronyms can seem confusing. Let start from scratch with some genetics for beginners before we dive inte them!
Horse Genetics for Beginners
There is a lot going on behind the scenes when an egg and sperm combine to form a foal. The way characteristics handed down from the mare and stallion mix determines size, color, temperament, and even certain elements of health. Genetics is the science that underpins all of this, and it is a complex and intriguing process. This is how it works.
Every horse has 32 pairs of chromosomes within each cell that carry all of the genetic information that makes him who he is. One set of these pairings came from his dam through the egg, while the other came from the stallion through the sperm. These chromosomes contain about 30,000 genes, or particular signals, that influence various characteristics.
Genes can be dominant (they are expressed even if they are only found on one set of chromosomes) or recessive (a matching pair must be present to have the trait in question). Some genes have incomplete dominance, which means that the characteristic is most strongly expressed when both sets of genes are present, but it can still be present even if only one gene is present. Here’s an illustration of how it works.
Assume that patience is a dominating characteristic, represented by a capital P. A little p indicates that your horse (or mare) lacks the patience gene. One gene comes from your stallion’s dam and one from his father. The following combinations are possible.
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Combination 1: PP.
Your stallion inherited a patience gene from each parent and is hence homozygous for patience.
Not only will he stand in the crossties for hours without complaining, but if mated, he’ll pass on a patience gene to his progeny as well.
Combination 2: Pp. Your horse inherited patience from one parent but not the other. He is patience heterozygous. He’ll remain patient despite the fact that the gene is dominant. He’d be patient if the patience gene had partial dominance, but not as patient as he would be if he were PP. If he is bred, only half of his kids will get the patience gene. The other half will be determined by their dams as to whether they will be patient.
When it comes to the patience gene, your stallion is homozygous recessive. He is not patient, and his children will only be patient if they acquire the patience gene from their mothers. Let’s alter our situation and say the patience gene is recessive, which means it’s only expressed if both genes are present. In this case, “p” represents patience, and your stallion will only be patient with
Combination 3. pp. Although he would have the gene in Combination 2 (Pp), no one would know since he would be impatient. Half of his children would receive the gene, but they would only be patient if their dams acquired another patience gene (making them pp). And there’s no way any of your stallion’s kids would be patient if he were PP.
Let’s take a look at the five heritable illnesses that have been found in stock breeds and tested for using the five-panel genetic test. Hyperkalemic periodic paralysis (HYPP), polysaccharide storage myopathy (PSSM), glycogen branching enzyme disease (GBED), hereditary equine regional dermal asthenia (HERDA), and malignant hyperthermia are a few examples (MH).
Glycogen Branching Enzyme Deficiency (GBED)
Glycogen Branching Enzyme Deficiency suggests a GBE1 gene mutation. This illness impairs the glycogen branching enzyme’s ability to operate properly. All three organs are affected: the liver, the brain, and the heart muscle. They will be unable to store or use glycogen effectively. This results in severe muscular weakness and, in extreme cases, death.Glycogen Branching Enzyme Deficiency suggests a GBE1 gene mutation. This illness impairs the glycogen branching enzyme’s ability to operate properly.
All three organs are affected: the liver, the brain, and the heart muscle. They will be unable to store or use glycogen effectively. This results in severe muscular weakness and, in extreme cases, death.
A horse with this condition should not be bred because their offspring have a high potential to have it and be stillborn before birth. Most that do survive do not live past four months of age.
Malignant hyperthermia (MH)
Stress or the use of certain anesthetics and muscle relaxants can trigger malignant hyperthermia. Rigid muscles, shallow breathing, irregular heart rhythms, and excessive perspiration are just a few of the early warning signs. This is one of the more treatable issues that a horse might encounter. A diet low in fermentable fiber, fat, and carbohydrate will be quite beneficial.
Hyperkalemic Periodic Paralysis (HYPP)
A mutation in the sodium channel gene causes hyperkalemic periodic paralysis. In horses with this gene, normal electrical impulses that allow muscles to contract do not function properly. Muscle tremors are the first sign, followed by the potential of paralysis. A horse suffering from HYPP may collapse and die at any time.
Hereditary Equine Regional Dermal Asthenia (HERDA)
Hereditary Equine Regional Dermal Asthenia is more prevalent in Quarter horses. If they were bred with a Quarter horse, the Paint and Appaloosa may also be impacted. To produce offspring with this gene, both the male and female horses must have it. The skin is affected by HERDA. It causes sores, scarring, and may even leave huge, open wounds.
Polysaccharide Storage Myopathy (PSSM)
Polysaccharide Storage Myopathy is the result of yet another mutation. It is prevalent in the majority of horse breeds, with at least 20 breeds susceptible to this issue. Excess sugar is present in the cells of the muscles as a result of uncontrolled glycogen flow. This results in stiffness, discomfort, and extreme weakness.
How Do DNA Tests for Horses Work
A DNA test for horses compares samples in a laboratory. Hair from the horse’s mane is most commonly used as a sample. To confirm genuine parentage, the DNA profiles of the mother, foal, and possible father are all thoroughly examined. It provides insight into the traits of a horse that may have been handed down from one or both of its parents. To obtain these results, the test analyzes 23 DNA markers.
How to Extract Horse Hair for DNA Testing
Any hair may be extracted for DNA testing, but not just any hair. The procedure must be followed precisely in order to obtain a valid sample. The hair sample should be taken above the withers of the mane. Cutting is not an option because the actual hair follicle is required for testing. This is where the DNA is kept. For foals, the procedure may differ. Young horses’ hair follicles are considerably finer, and they may break more easily when you pull them.
In this scenario, the tail will give a superior sample. In all cases, it is critical to collect around 20-30 hairs, or however many your testing organization advises, to ensure that there are enough to be thoroughly examined. Several may be broken or damaged, therefore having lots of spares on hand is essential.
Horse Genetic Testing Options
The most frequent choice is to use horse hair, although it is not the only one.
It is also feasible to do genetic testing on blood samples 1 and even sperm. Hair is the most easily available, which is why most breeders and horse owners prefer it. If you want to experiment with different methods, you should first check with your horse’s veterinarian to verify that the correct instruments and technique are utilized to obtain an accurate sample to send in.
Is it true that every horse has a unique DNA profile?
If you’re wondering if every horse has a different DNA profile, the answer is yes. Every organism has its own unique DNA, which must be carefully analyzed in order to get essential information on the identifiers that make up its genetic makeup. Millions of dollars were spent on the horse genome project to generate a database of DNA pairs that scientists may use to detect both behavioral and physical variations in horses. Horses have 31 autosomes and two sex chromosomes, according to this study.