Sabino-1 (Coat colour pattern Horse)
Horses with the Sabino-1 pattern often have white patches of different sizes with 'indistinct/fringed' borders especially on the head, belly and legs. Many horses have often white ticked hair on the rest of the body (animals with one copy of the gene: Sb1/n). Horses with two copies of the mutation (homozygous) are usually completely white.
Sabino-1 is a special form of White Spotting/Dominant White and is the most common, but not the only mutation causing this spotting pattern. Should a horse show a Sabino-like pattern but does not have an Sb1 mutation, other mutations in the KIT gene, the so-called W-variants, could be responsible.
General Information
- White patches of different sizes with indistinct/fringed' borders (especially head, belly and legs).
- Horses with one copy of the mutation (heterozygous) have often white ticked hair (varnish white).
- Horses with two copies of the mutation (homozygous) are usually completely white.
- Sb1 is the most common, but not the only mutation causing this coat pattern.
- Sabino-1 (Sb1) is a special form of White Spotting/Dominant White.
- If a horse shows a Sabino-like spotting pattern but does not have an Sb1 mutation, other mutations in the KIT gene, the so-called W-variants, could be responsible or mutations not yet known.
- Breeds that may have the Sabino-1 coat pattern are: Tennessee Walking Horse, Miniature Horses, Paints, Aztec, Missouri Foxtrotters, Shetland, Spanish Mustang and Pony of the Americas
Test Information
Locus Information: SB-Locus
It is a change of a single basepair in the KIT gene.
Genotype and Lab Report
Inheritance: incomplete autosomal-dominant
→ Incomplete means that animals with only one copy of the variant (Sb1/n) will show a less pronounced phenotype than horses with two copies of the variant (Sb1/Sb1).
Genotype
n/n = No copy of the Sabino-1-variant
No coat pattern.
Sb1/n = One copy of the Sb1-variant
Pattern with indistinct white patches and/or white on head and legs. Phenotype is very variable.
Sb1/Sb1 = Two copies of the Sb1-variant
Often completely white coat or only small remnants of color (often ears).
Appearance
Sabino Pattern
White irregular patches on the head, legs and belly and white ticked hair on the body.
e/e Sb1/n
Sabino Pattern
White patches with 'indistinct/fringed' borders.
ee Sb1/n
Literature
Brooks, SA., Bailey, E.: Exon skipping in the KIT gene causes a Sabino spotting pattern in horses. Mamm Genome 16:893-902, 2005. Pubmed reference: 16284805. DOI: 10.1007/s00335-005-2472-y.
Further information is available at Online Mendelian Inheritance in Animals.