Two separate research teams have identified the myostatin gene as a crucial indicator of athletic ability in a Thoroughbred's genetic makeup and are continuing to study the potential of this marker for race distance selection.

Emmeline Hill, PhD, and a team of researchers from the University College Dublin discovered earlier this year that a mutation of the gene myostatin greatly impacts a racehorse's athletic ability. Hill's team discovered that horses with the particular mutation have increased muscle mass.

The team used the Equinome Speed Gene test to analyze the DNA of nearly 150 Thoroughbreds. The results of the test indicated at what distance–short, medium, or medium-long races–a horse would likely be most competitive. Since the initial study, the team has that the Equinome Speed Gene marker is the most sensitive genetic marker in the genome for the prediction of race distance aptitude in Thoroughbreds.

More recently, a team of researchers working at the Japanese Laboratory of Racing Chemistry conducted a similar test and obtained comparable results. Teruaki Tozaki, PhD, the leader of the Japanese team, also found that the characteristics of the area surrounding the myostatin gene had a great bearing on the athletic ability of the horses tested, suggesting that racing performance or athletic ability is a hereditary trait