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Locus Information: SLC24A5 gene

Inheritance: autosomal-recessive

→ Only animals with two copies of the variant (te/te) show the respective phenotype. Animals with only one copy (N/te) are carriers.

General Information:

  • Eye color is bright yellow, amber or orange.
  • Eye color depends on the form and the amount of melanin that is stored in the iris.
  • The SLC24A5 gene is involved in the maturing of melanocytes (melanocytes produce melanin).
  • Two variants of this gene that cause tiger-eye-1 (te1) and tiger-eye-2 (te2) are known. Another causal mutation may cause this phenotype that could not yet be identified.
  • The vast majority of horses showing this phenotype have two copies of the te1 mutation or are heterozygous for both mutations (te1/te2).
  • The phenotype of te2 homozygotes (te2/te2) has not been completely described yet.
  • Tiger eyes have only been recorded in the Paso Fino (Puerto Rico) but are also believed in to occur in related breeds.

Possible Genotypes:

Genotype: Effects:
N/N No Tiger-Eye mutation (neither te1 nor te2).
N/te1 or N/te2 The horse has one copy of the TE-variant → it is a carrier for this variant but does not show the respective phenotype itself.
te1/te1 or te1/te2
The horse has two copies of the TE-variant → the horse shows the yellow, amber or orange eye color.
te2/te2 The horse has two copies of the TE2-variant → phenotype not yet described.


Test information: This test detects two different variants in the SLC24A5 gene.

Mack M, Kowalski E, Grahn R, Bras D, Penedo MCT, Bellone R.: Two Variants in SLC24A5 Are Associated with “Tiger-Eye” Iris Pigmentation in Puerto Rican Paso Fino Horses;

Further information is available at Online Mendelian Inheritance in Animals.

Test #: H224

Samples: Blood, Hair

Price: 35 € (net)

Time required: 10-14 days

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