The Silver dilution gene dilutes the black pigment but has no effect on the red pigment. El efecto del gen de dilución Plata puede variar mucho. La crin y la cola se abrillantan a lino o gris plata y pueden oscurecer en algunos caballos conforme envejecen. Un caballo negro se diluirá al chocolate con un aclarado de la melena y la cola. Un caballo bahía con dilución Plata tendrá generalmente un aclarado en crines y cola, así como en la parte baja de las patas (lugares con pigmento negro). A horse can also carry mutations for other modifying genes which can further affect its coat colour.
The Coat Colour Silver dilution test (P784) tests for the genetic status of the PMEL17 gene. Este gen tiene dos variantes (alelos). El alelo dominante Z resulta en la dilución y el alelo recesivo N no tiene un efecto sobre el color básico.
The same mutation responsible for the coat color Silver is also associated with Multiple Congenital Ocular Anomalies (MCOA) Syndrome, a wide range of ocular defects that occur in the anterior and posterior parts of the eye. La gravedad del síndrome está relacionada con la dosis, por lo que los caballos con 1 copia del alelo Z tienen menos signos graves que aquellos con 2 copias del alelo Z.
The Coat Colour Silver dilution test encloses the following results, in this scheme the results of the Coat Colour Silver dilution test are shown in combination with the possible results for the tests that determine the basic Coat Colour (Coat Colour Chestnut and Coat Colour Agouti test):
|
Result Silver dilution |
Result Chestnut + Agouti |
Coat Colour |
Descripción |
|---|---|---|---|
|
N/N |
e/e + A/A, A/a or a/a
|
Chestnut, Sorrel
|
Non-dilute. The basic colour chestnut/sorrel is not modified unless modified by other colour modifying genes. It can only pass on allele N to its offspring. |
|
N/N |
E/E or E/e + A/A or A/a |
Bay, Brown |
Non-dilute. The basic colour bay/brown is not modified unless modified by other colour modifying genes. It can only pass on allele N to its offspring. |
|
N/N |
E/E or E/e + a/a |
Black |
Non-dilute. The basic colour black is not modified unless modified by other colour modifying genes. It can only pass on allele N to its offspring. |
|
N/Z |
e/e + A/A, A/a or a/a
|
Chestnut, Sorrel
|
One copy of the dominant Z allele. The basic colour chestnut/sorrel is not modified unless modified by other colour modifying genes. It can pass on either allele N or Z to its offspring. |
|
N/Z |
E/E or E/e + A/A or A/a |
Silver dilution on Bay or Brown |
One copy of the dominant Z allele. The black pigment of bay/brown horses on lower legs is lightened and mane and tail are lightened to flaxen. The colour can be further modified by other colour modifying genes. It can pass on either allele N or Z to its offspring. |
|
N/Z |
E/E or E/e + a/a |
Chocolate |
One copy of the dominant Z allele. The basic colour black is diluted to chocolate with flaxen mane and tail. The colour can be further modified by other colour modifying genes. It can pass on either allele N or Z to its offspring. |
|
Z/Z |
e/e + A/A, A/a or a/a
|
Chestnut, Sorrel
|
Two copies of the dominant Z allele. The basic colour chestnut/sorrel is not modified unless modified by other colour modifying genes. It can only pass on allele Z to its offspring. |
|
Z/Z |
E/E or E/e + A/A or A/a |
Silver dilution on Bay or Brown |
Two copies of the dominant Z allele. The black pigment of bay/brown horses on lower legs is lightened and mane and tail are lightened to flaxen. The colour can be further modified by other colour modifying genes. It can only pass on allele Z to its offspring. |
|
Z/Z |
E/E or E/e + a/a |
Chocolate |
Two copies of the dominant Z allele. The basic colour black is diluted to chocolate with flaxen mane and tail. The colour can be further modified by other colour modifying genes. It can only pass on allele Z to its offspring. |