Coat colour Splashed White 3 / SW3 (MITF-related) - Horse

What does this test examine?

This DNA test examines the MITF variant c.519_523delGTGTC, known as Splashed White 3 / SW3, in horses. Splashed White is also described as white spotting, splash or SW and belongs to the coat-colour patterns in which pigment is absent in specific areas.

What does Splashed White mean?

Splashed White can produce a broad blaze, extended white leg markings, white areas on the belly, pink skin under white hair and blue or partly blue eyes. The amount of white can vary widely: some horses show a clear splash pattern, while others look more subtle or also carry other white-pattern alleles. SW3 is rare, and the homozygous state is considered likely embryonic lethal, making this result especially important for mating decisions.

Inheritance and result

SW3 is inherited as an autosomal incomplete dominant trait. One copy can cause the pattern; two copies can produce a stronger effect or have a different biological meaning for certain SW variants. Other loci for base colour, dilution and white spotting still influence the final appearance.

Practical value of this test

• Confirms whether a visible or subtle white pattern is explained by this specific SW variant.
• Helps breeders plan matings by showing whether the horse can pass the variant to foals.
• Makes colour planning more reliable when several white-spotting variants, such as Tobiano, Sabino or other SW alleles, occur together.
• Supports registration, sale and breeding communication with clear genetic information about the coat pattern.