White-spotting Gene W35 Adds More Opportunities for Paint Breeders

By Jessica Hein, PHJ News

W35 is the newest spotting pattern in the Paint Horse lineup, thereby giving Paint Horse breeders another opportunity to keep chrome in the breed.

Researchers at Etalon Diagnostics discovered W35 in 2023. The discovery was published in the May 12, 2023, issue of the peer-reviewed Journal of Equine Veterinary Science.

The W35 spotting pattern is a mutation of the KIT gene, which is also home to Sabino 1 and more than 30 “W” mutations that can cause white spotting patterns. This allele tends to produce white markings on the face and legs, Etalon CEO Christa Lafayette says.

APHA member Branson Buckalew helped researchers identify the W35 spotting pattern; his overo stallion A Sudden Holiday (above photo) was among the horses used for research.

“I am ecstatic this new color marker has been identified and that I played a small part in the discovery,” Branson said. “This new color marker could open up the door for Regular Registry on a lot of horses that previously did not qualify but possess unexplained characteristics.”

Regular Registry Opportunities

W35 and other white-spotting patterns can help a Paint Horse earn Regular Registry status. The RG-070.E. rule advances a horse to Regular Registry if it meets requirements including presence of Paint trait(s) and an eligible white spotting-pattern gene. Testing must be from an APHA-approved lab.

Eligible white-spotting patterns: Tobiano, Frame Overo, Sabino 1, Splashed White 1/2/3/5/6/7, W5/10/20/22/31/32/34/35

Submit your status change to APHA by mail, including:

• The horse’s original APHA registration certificate
• Request for Corrected Certificate form
• A copy of the DNA testing
• Photos of the applicable trait(s)
• Payment for fees

APHA partner lab Etalon offers W35 testing as an a la carte option.

Photos courtesy Buckalew Show Horses (top), Danelle Griffin (bottom right) & Jaime Foutty (bottom left) – both photos provided by APHA.