Genetic Research is a New Tool in Breeding

The quest to breed a better horse has led Thoroughbred breeders to try many unorthodox theories and systems, all with mixed results.

To date, the success (or lack thereof) of most of these tools has been anecdotal, with no way to quantify whether a horse's achievements were due to one or more of these breeding aides. Now, thanks to the rapidly developing advances within DNA collection and testing, the quest for a better-bred Thoroughbred is becoming more scientific than theoretical in nature.

That was the focus of the first Thoroughbred Pedigree and Genetics Symposium in Lexington, Ky., on Oct. 11, as about 175 industry professionals heard presentations from some of the leaders in the field of equine genetics research. The seminar was presented by The Blood-Horse and the Pedigree Consultants firm of Alan Porter and Byron Rogers.

Much of the groundwork for current advances within equine DNA traces back to the Equine Genome Project, a cooperative effort in more than 20 countries that set out to define the genome--the DNA sequence--of the domestic horse. The genome is the total amount of genetic information in the horse's 64 chromosomes.

Studying DNA through various "markers" enables scientists to identify genes that combine to produce certain traits within the horse, including whether the horse is predisposed to speed or distance. In addition, DNA study can be useful in helping researchers find new therapies and treatments for diseases.

During the Pedigree and Genetics Symposium, participants were dealt a heavy dose of highly technical but fascinating material on the potential benefits to the breed from DNA study. A DVD containing all of the symposium's presentations will be released later.

However, most of the presenters emphasized that even with the sophisticated information gleaned from analyzing a horse's genome, it is not ironclad and should be used to complement other breeding tools.

In his review of the history of pedigree analysis and other breeding tools, Porter noted that there is now greater access to information that once was time-consuming and costly to obtain. Among the major developments within Thoroughbred pedigree research are programs that analyze nicking patterns within a horse's pedigree, such as the TrueNicks product developed by Porter and Rogers.

"The developments probably raise as many questions as they answer," Porter said. He said the industry is "at a point now where everybody has access to information; what is important is how to interpret that information."

Even with all the developments currently underway, Porter said there is no assurance that use of this information will lead to better bred horses.

"Is this going to allow us to breed a faster or better horse? That's a very good question," Porter said. "In terms of whether we are going to improve the ability of the upper end of the breed, under the current best practices in breeding, I think it is highly unlikely. Personally, I would hypothesize the horse reached the upper end of its evolution as a runner somewhere around 40 years ago.

"The goal of breeding a Thoroughbred has always been to breed the best possible horse," Porter continued. "I think we are not so much trying to buy or breed a superhorse, although that may still be possible, but more using our skills and our technology to breed or buy horses that don't have the potential to be elite athletes."

James MacLeod, VMD, PhD, John S. and Elizabeth A. Knight Chair, professor of Veterinary Science at the Gluck Equine Research Center at the University of Kentucky, explained how the Equine Genome Project was undertaken, some of the tools used in genetic research, and how its results can be applied.

"These are powerful new tools that will enhance and enable good horsemanship," MacLeod said.

In a major genetic research breakthrough announced at the symposium, Emmeline Hill, PhD, equine genomics researcher at the University College Dublin School of Agriculture, Food Science, and Veterinary Medicine, reported that a scientific study has confirmed the "genetic marker used in the Equinome Speed Gene Test to identify the optimum racing distance for individual Thoroughbred horses is the most powerful indicator of its type."

Hill, a co-founder and chairman of Equinome, a genetics company based in Ireland, said her company's genetic marker "performs 15 times better than any other marker in predicting best racing distance."

Steven Tammariello, PhD, associate professor at Binghamton University, and founder of ThoroughGen, delivered a detailed explanation of using genetic testing in the area of molecular physiology in both humans and horses.

He explained that early DNA sequencing was performed in an effort to "come up with a genetically superior horse." Now, however, he said it had evolved to where "we are interested more in what you want to avoid."

Matthew Binns, PhD, a consultant for Equigen LLC and The Genetic Edge, explained how his research found markers with predictive value for preferred distances, preferred surfaces, and racing ability.

He said his study was conducted on the genome of more than 1,000 horses, including 200 grade I winners.

"Our data predicts that you can eliminate 50% of individuals on a short list and retain 75% of the graded stakes winners," Binn said of his conclusions.

Binns said that using only his DNA tests he was able pick six graded stakes winners from a group of 55 horses.

Robert Fierro of Datatrack International, outlined trends within North American breeding that have changed horse biomechanics over the decades to meet changes within the international racing industry. Using a chart, Fierro showed how some leading sires compared when looking at their power and stride attributes.

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Photos by Diana DeRosa - Steffan Peters and Edward Gal