Knowing a horse's genome could pay off big at the race track.


- A new genetic test could identify a horse's ideal racing distance.

- Variations in a gene responsible for muscle cell production separate long-distance runners from sprinters.

- Although the test costs $1,400, training a horse costs tens of thousands of dollars.

Equinome, a horse genome sequencing company based in Ireland, has developed a new genetic test to identify a horse's ideal racing distance based on a gene that encodes for muscle development. The research could help horse breeders and trainers pick a horse with winning potential.

"Human studies have found over 200 genes responsible for an individual's health and fitness," said Emmaline Hill, Chairman of Equinome. "We also expected a large number of genes would contribute to a horse's performance, so we were surprised when we identified one gene with such a large effect."

Known as MSTN, the gene regulates myostatin, a protein that controls muscle cell production. There are three different variants of the myostatin gene a horse can inherit: TT, CC and CT. Horses with the TT version develop muscles later in life. Horses with the CC version develop their muscles earlier.

To find the myostatin gene, Hill and his colleagues started with 179 race horses that were two years old. They divided the horses into two groups based on their past professional racing performance over short and long distances. The scientists then sequenced the DNA of all the horses and compared the results.

With one exception, all thoroughbred long distance race winners had the TT version of the gene. With no exceptions, all thoroughbred short distance race winners had the CC variant. The team's findings were published in the journal PLoS One.

The 2010 research matches with an earlier paper the group published in 2008 comparing short distance English racing horses with Arabian horses that compete in long distance endurance races.

English horses, which have been historically bred for shorter distance, had the CC variant. Egyptian raised Arabian horses that compete in cross desert endurance racing of the kind featured in the film "Hidalgo" had the TT variant.

For the last 300 years, horse breeders have been unwittingly choosing a particular variant of the gene. Now Equinome is offering a test for the gene costing about $1,400 (1,000 euros).

This fee might seem like a lot of money. However, considering that tens of thousands of dollars are spent on a horses training during its first couple of years, the test is worth it, says Hill.

Using a five-milliliter sample of a newborn horse's blood and Equinome's equipment will tell a breeder which distance the horse is best suited. Hill doesn't guarantee that the horse will win at that distance, just that they will be better at one distance versus another.

"What (horse trainers) do now is take horses not knowing what distance they are good for and, after a lot of time and expense, find out what distance they are best at," said Ernest Biley, a horse researcher at the University of Kentucky. "This new test might make it possible to winnow out horses that won't be successful at certain distances."

"I expect (the new test) will change the way horses are managed. You will know whether it is worth putting a young horse in a training program for long- or short-distance work," said Claire Wade, a scientist now in Australia who helped sequence the horse genome. "I don't think that it will impact breeding decisions because these are made on the basis of racing success in the parents."

Ultimately a horse's racing success isn't determined by one single gene. The myostatin gene has a significant impact, but there are dozens of other genes that likely play a part in determining a horses performance on and off the track. Even Hill says that her companies test won't guarantee winners.

"What we've done here is identified the gene that tells an owner at what distance the horse will be best at," said Emmaline Hill, Chairman of Equinome. "However, it doesn't tell an owner if the horse will be any good."