The Appaloosa spotting pattern, also known as Leopard Complex spotting (LP) includes a highly variable group of white spotting- or depigmentation patterns in horses. Appaloosa horses have three additional identifiable characteristics: mottled skin around the muzzle, anus and genitalia, striped hooves and white sclera round the eyes. LP is the result of an incompletely dominant mutation in the TRPM1 gene, also known as the LP gene. The LP gene allows for the expression of the various leopard complex spotting patterns while other genes determine the extent (or amount) of white. One of the genes that is associated with increased amount of white in in LP horses has been identified (RFWD3) and has been termed Pattern-1 (PATN1) for first pattern gene. The Coat Colour Appaloosa Pattern-1 (PATN1) test (P305) tests for the status of the PATN1 gene. This gene has two variants (alleles). The dominant allele PATN1 results in an increased amount of white in horses that carry at least one copy of the LP allele on the LP gene. The recessive allele N does not have an effect on the basic colour. Horses that have one copy of the LP allele, in combination with at least one copy of the PATN1 allele most often have a Leopard or a near Leopard pattern. Horses that have two copies of the LP allele in combination with at least one copy of the PATN1 allele most often have a Few-spot or near Few spot pattern. Horses that have at least one copy of the PATN1 allele but do not have a copy of the LP allele will not have a Appaloosa spotting pattern but can pass on the PATN1 allele to their offspring.
The Coat Colour Appaloosa Pattern-1 (PATN1) test encloses the following results, in this scheme the results of the Coat Colour Appaloosa Pattern-1 (PATN1) test are shown in combination with the possible results for the LP Gene.
|
Result PATN1 |
Result LP |
Coat Colour |
Description |
|---|---|---|---|
|
N/N |
N/N |
No Appaloosa |
The basic colour is not modified unless modified by other colour modifying genes. It can only pass on allele N to its offspring. |
|
N/N |
N/LP |
Blanket appaloosa |
It can only pass on allele N to its offspring. |
|
N/N |
LP/LP |
Snow cap appaloosa |
It can only pass on allele N to its offspring. The horse suffers from Congenital Stationary Night Blindness (CSNB). |
|
N/PATN1 |
N/N |
No Appaloosa |
The basic colour is not modified unless modified by other colour modifying genes. It can pass on either allele N or PATN1 to its offspring. |
|
N/PATN1 |
N/LP |
Leopard or a near Leopard pattern |
It can pass on either allele N or PATN1 to its offspring. |
|
N/PATN1 |
LP/LP |
Few-spot or near Few spot pattern. |
It can pass on either allele N or PATN1 to its offspring. The horse suffers from Congenital Stationary Night Blindness (CSNB). |
|
PATN1/PATN1 |
N/N |
No Appaloosa |
The basic colour is not modified unless modified by other colour modifying genes. It can only pass on allele PATN1 to its offspring. |
|
PATN1/PATN1 |
N/LP |
Leopard or a near Leopard pattern |
It can only pass on allele PATN1 to its offspring. |
|
PATN1/PATN1 |
LP/LP |
Few-spot or near Few spot pattern |
It can only pass on allele PATN1 to its offspring. The horse suffers from Congenital Stationary Night Blindness (CSNB). |
