Brindle / BR1 coat pattern (MBTPS2-related) - Horse

What does this test examine?

This DNA test examines Brindle 1, also known as BR1, in horses. The analysis detects the MBTPS2 variant c.1437+4T>C. BR1 is an X-linked coat-colour and coat-texture variant best known for vertical striping or a brindled pattern, often together with differences in coat texture, mane and tail hair.

What does Brindle mean in horses?

In female horses, one BR1 copy can create a mosaic-like pattern with vertical stripes or areas where coat texture and pigment distribution differ. Visibility depends on base colour, other colour genes and the individual pattern of X inactivation. In male horses, interpretation is different because males carry only one X chromosome, so genotype and sex must be considered together in reporting.

Practical value of this test

• N/N or N: the BR1 variant is not detected.
• N/BR1: one BR1 copy; in mares this can cause the characteristic brindled pattern.
• BR1/BR1 or BR1: double-copy or hemizygous presence; reporting should be interpreted together with the animal’s sex.

The result helps breeders and owners confirm the unusual Brindle pattern genetically, include BR1 in breeding decisions and reduce confusion with non-heritable or other pattern types.