The Appaloosa horse descended from horses brought to American by the Spanish in the 16th century. The name Appaloosa comes from the Palouse river that ran through the Nez PercÚ Indians territory. The breed is best characterized
by its spotted coat pattern commonly referred to as "leopard-complex". The leopard-spotted coat pattern has also been documented in several other horse breeds, including the Pony of the Americas, the Nez PercÚ Horse
and several gaited horse breeds.
Within the Appaloosa breed there is a wide range of body types, stemming from the influence of multiple breeds of horses including Arabian blood lines, which where
introduced during the late 19th century. Although commonly recognized by their colorful coat patterns Appaloosa horses have three additional identifiable characteristics including mottled skin around the nose, lips, and genital, striped hooves, and white sclera round the eyes.
In 2003 researchers linked the positional candidate gene for leopard complex (LP) to the TRPM1 gene on chromosome 1. Further investigations headed by Dr. Rebecca Bellone and The Appaloosa Project (a team of researchers from Canada and the US) identified several SNPs in TRPM1 showing complete association. Soon after that, the causal mutation was also discover. Both the SNP's and the causal mutation can be used to develop a genetic test to identify horses with leopard complex.
Congenital Stationary Night Blindness (CSNB)
It has long been understood that Appaloosas are affected be both Equine Recurrent Uveitis and Congenital Stationary Night Blindness (CSNB) a condition making it difficult or even impossible to see in relatively low light.
Research has now shown that CSNB is a recessive disorder that is directly linked to the leopard complex in Appaloosa horses.áDNA test for the LP mutation can also provide clear information as to CSNB.
Genetic testing of the leopard complex (LP) gene may be beneficial for several reasons: First reason for testing is to confirm that an animal is a true appaloosa horse. Another important reason is to identify those animals that are homozygous or LP/LP and will be affected by CSNB. Animal Genetics offers DNA testing for the associated gene mutations for LP.
US per sample.
Collect sample by pulling (not cutting) 20-30
mane or tail hairs with roots attached. It is important that you
pull the hairs and confirm that the actual root of the hair is being
collected. The root contains the genetic material of your horse
that is needed for DNA testing. Therefore, cut hairs do not provide
an adequate sample of your horse. Place the collected hairs of each
horse in a separate zip-lock bag labeling the bags accordingly with
the horses name or identification number. Download and complete
a submission form for each sample and send along with
payment to Animal Genetics for testing.
Animal Genetics offers DNA testing for leopard complex (LP). The genetic test verifies the presence of the LP gene and presents results as one of the following:
|Indicates the animal carries two inherited copies of the LP gene. Homozygous LP horses are genetically bound to pass the gene to 100% of their progeny when bred, and all foals will be LP horses. Additionally, horses that test homozygous positive for LP will be affected by CSNB. Thus, appropriate measures must be taken to prevent possible harm to both the animal and its caregivers.
|Heterozygous for the LP gene and carries a single inherited copy. Heterozygous LP horses are statistically likely to pass the gene to 50% of their progeny when bred.
|Negative for the LP gene and should not exhibit characteristics associated with the Appaloosa phenotype.