Coat colour Splashed White 2 / SW2 (PAX3-related) - Horse

What does this test examine?

This DNA test examines the PAX3 variant c.209G>A, known as Splashed White 2 / SW2, 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. The name Macchiato appears in the white-spotting context, but this analysis specifically assesses the PAX3 SW2 variant.

Inheritance and result

SW2 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.