Here in Dublin, I got a glimpse into what could be the future of Thoroughbred breeding.
Our group with the University of Louisville's Equine Industry Program was invited for a private lecture by one of the world's leading equine geneticists, Dr. Emmeline Hill at University College Dublin. In 2009, Dr. Hill and a team of researchers said they had identified a group of genes that contributed to athletic performance in Thoroughbreds. Hill, along with Irish racing trainer Jim Bolger, formed a company called Equinome, which offers a DNA test based on Hill's research.
Hill's findings have been greeted with a mixture of excitement and skepticism. Tim Morris, director of equine science and welfare for the British Horseracing Authority, said in a speech on the subject: “The performance gene is not the focus of British racing research, because first, it's not wanted and second, it doesn't exist.”
Her research so far has focused on distance proclivities for Thoroughbred runners, and the evidence is compelling. Without getting too much into the science (because frankly, I can't explain it all) the horse genome has more than 2.7 billion “letters” or nucleotides on it. These letters – G, A, T and C – form a mind-boggling array of potential outcomes as DNA is passed from one generation to the next. One letter being changed in one particular location can have a profound impact.
Hill discovered that in one location responsible for muscle mass development, a horse can either have a C or a T. Each horse gets one letter from its sire and one letter from its dam, so there are three possible combinations: CC, CT or TT.
A study of race results from Group and Listed races in England and Ireland found a very strong correlation between runner types and winners. Of the CC winners, more than 70 % won at 5-6 furlongs and an astounding 98% won at a mile or less. In other words, a CC horse had almost no chance of winning at a distance over a mile.
CT horses were found to have a mixture of speed and stamina, so their optimum range was 7 – 12 furlongs, and the race results confirmed that. TT horses in the study rarely won races under 10 furlongs. They are the stayers.
Furthermore, CC and CT horses tend to develop faster than TT types, so if you're looking for precocious runners, the TTs are a bad bet. In a study of 142 two-year-old runners by the same trainer, CC and CT horses won, on average, 5.5 times more in earnings than TTs. No TT horses won a Group race as a two-year-old (two-year-olds here don't race over a mile).
My first reaction was that we already know this. Astute pedigree researchers can look at bloodlines and determine whether a horse will like sprinting, middle-distance or stamina races. But this research takes it to a whole new level of certainty. If you have a dam and a sire that are both CTs, there's a 50% chance of producing a middle-distance CT offspring. But there's also a 25% chance of getting a CC sprinter type and a 25% chance of getting a long-distance TT runner. Without the test, there's no way of knowing which type of offspring has been produced.
The practical applications are numerous. Breeders, owners and trainers could identify the most precocious prospects. Which runners are likely to show well at the yearling sales or sparkle at the two-year-old under tack shows?
For horses in training, there might be less time wasted trying to figure out optimal distances. Broodmare owners could use the information to better select a compatible stallion based on the breeding goal. The owner of a CC mare who wants to produce a middle-distance runner isn't going to get it by mating with a CC stallion. Similarly, TT stallion owners looking for precocity in their offspring may want to focus on CC mares. A TT mare would have almost no chance of producing an early-developer with a TT stallion.
Equinome is one of several companies providing DNA testing products to the racing industry, but Hill's research may be the most transparent. Some of her competitors talk about performance genes, racing genes and energy genes, but it's not altogether clear on what research these products are based. Hill has filed for an international patent to protect her findings. I wouldn't be surprised to see court cases over this in the future.
Distance proclivity may only be the beginning. Who knows what these scientists might find as they continue to dig deeper into the genome? I asked Hill if she thought about the long-term possibilities – could this research eventually take the mystery and enjoyment out of the sport? No, she said. Genetics are only half the equation. There will always be the environmental influences, such as training methods, nutrition and care that play a major role as well.
The biggest benefit of DNA testing could be efficiency in the industry. Hill said foal crops should be more finely-tuned, meaning fewer horses that don't make it to the track, fewer horses being run at the wrong distance and then discarded and in general, fewer unwanted horses in the ranks, a potential benefit for Thoroughbred retirement.
An Equinome DNA test goes for about $850 U.S. per horse, and only owners with registration papers can purchase a test. A buyer can't go to a sale and ask for a yearling he's interested in to be tested (results take 24 hours or so anyway), but a consignor could test his horses and have the information ready for interested buyers.
Hill said she wants the Thoroughbred industry to embrace DNA testing by seeing the results rather than her trying to force the science upon people – a strategy she believes will fail. So far, she's seeing quite a bit of interest from Australia and Asia.
Hill's company – and this science – is still in its infancy, so questions abound about where it's headed. But it certainly seems like there's tremendous potential for making the breeding industry much more efficient. What are your thoughts?
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