Etalon Equine Genetics Discovers Two New Genetic Variants in Pura Raza Española Horses for Blue Eyes

Pura Raza Española horses are world renowned for their Spanish beauty. But, have you ever seen one with a white mask, tall stockings, and captivating blue eyes?

Step into the world of Yeguada Sierra de la Espada, owned by the Gil Torrano family, and prepare to be impressed by a herd of horses like no other. These magnificent creatures boast a rare and captivating beauty with their flashy white patterns which are exceptionally uncommon among PRE horses. It's a sight that takes your breath away and makes you wonder what makes them so uniquely stunning.

Discoveries are a team effort; they take place when horse owners ask questions, and Alberto Gil Torrano was confident there was something unique in the genetics of his herd. The mystery deepened when initial genetic analysis revealed that these horses didn't carry any previously known white mutations. Something extraordinary was unfolding, and the team at Etalon Equine Genetics knew they had to delve deeper into the story.

The Etalon research team, led by Aiden McFadden, began on a scientific journey to uncover the secrets behind these remarkable coat patterns. First, they implemented advanced sequencing technologies to explore each horse’s genetic code. A particular focus was specifically placed on the MITF and PAX3 regions which have been linked, in prior Etalon studies, to the “Splashed White” phenotype.

Through a meticulous comparison of the sequencing data with established genetic markers and reference genomes, the research team identified not one, but two previously undiscovered mutations: Splashed White 9 (SW9) in the MITF region and Splashed White 10 (SW10) in the PAX3 region. The study has now been published in the Journal of Equine Veterinary Science.

"After finding the first mutation, what would become SW9, I was surprised to see it didn't explain all of the white markings. Finding a second novel mutation in the same family is like getting two birds with one stone!" said McFadden.

To understand the functional impact of these mutations, the researchers utilized computational modeling tools which predict the impact of each mutation on a living animal. These assessments shed light on how the mutations influence the migration and pigmentation of melanocytes, the cells responsible for determining coat coloration in horses.

In addition to the genetic analysis, the horses were visually evaluated and their markings, or “phenotypes”, scored using established systems from previous genetic studies. This phenotypic assessment allows the researchers to establish a correlation between the presence of the newly identified mutations and the observed splashed white presence (or phenotype) in each horse.

Based on their findings, the research team proposed naming designation for the identified variants that followed both the standard science while paying homage to the horses in which they were discovered. The new mutations have been labeled, Splashed White 9/Giltor (SW9) for the MITF variant and Splashed White 10/Giltor (SW10) for the PAX3 mutation: a standing tribute to the Gil Torrano herd and adhering to established naming conventions in the field.

The discovery of these novel variants has far-reaching implications for our understanding of the genetic basis of splashed white phenotypes in horses. With this newfound knowledge, targeted breeding programs can be developed to preserve and manage these distinctive traits.

Etalon has now released testing for Splashed White 9/Giltor and Splashed White 10/Giltor. Tests for each variant are available for $79, or as a bundle for $149! Breeders can utilize Etalon’s equine genetic testing to identify horses carrying these specific variants and selectively breed them to perpetuate the splashed white coat patterns.