The Quarter Horse is considered by many a very versatile breed that excels in a variety of areas. So versatile, in fact, that over the years breeders have made efforts to separate the breed into different specialties, like racing-type Quarter Horses and cutting-type Quarter Horses. But is there any real genetic base to these “sub-breeds” of Quarter Horse? Science says yes—and now it has the haplotypes to prove it.

Brazilian researchers recently identified specific genes that distinguish racing-type Quarter Horses from cutting-type Quarter Horses. By analyzing the genome of hundreds of Quarter Horses used for either cutting or racing, the scientists singled out the haplotypes—DNA classifications based on close similarities of certain genome segments—that set the two types of horses apart. And they were able to locate exactly where those haplotypes are found on the genome.

“Our findings could lead to the development of genetic tests that indicate whether an individual has the propensity for sport,” said Camila Meira, PhD, of the College of Agriculture and Veterinary Science at São Paulo State University (UNESP). Meira worked with Rogério Abdallah Curi, PhD, and the late Marcilio Dias Silveira da Mota, PhD, both of UNESP, on the study.

Meira said she and colleagues identified regions in the genome that had been clearly affected by the selective breeding process over the last several decades in creating racing and cutting lines. They tested genomes from 188 Quarter Horses born between 1985 and 2009 and registered with the Brazilian breed association. About two-thirds of the horses were from establi