Hill Delves into World of Thoroughbred Genetics


Emmeline Hill

By Bill Finley

When it comes to the equine world and science, Emmeline Hill is one of Ireland’s–if not the world’s–brightest minds. She is an Associate Professor of Equine Science at University College Dublin as well as the Chief Science Officer for Plusvital Ltd., a world leader in the development and provision of genetic tests for the international thoroughbred breeding and horse racing industries. Hill has found ways to study the genes and DNA patterns of race horses and believes they provide a wealth of useful knowledge. Her biggest breakthrough so far as been the identification of the “speed gene.” She can now tell with a high degree of accuracy if a horse will do its best running as a sprinter, a middle distance horse or a router. Hill was the guest on this week’s Thoroughbred Daily News podcast, brought to you by Taylor Made, and we present here some of the more noteworthy excerpts.

TDN: At least here in the US, this is not a sport that embraces new ideas. How much resistance did you run into when you started to introduce your ideas and began throwing around scientific terms most trainers had probably never heard of?

EH: The interesting thing is everybody really understands genetics, whether they realize it or not. Any time you look at a pedigree page you are trying to infer, or make a best guess, about the genes that have been passed down from ancestors in a pedigree to the individual. Many people really intuitively understand genetics even if they don’t necessarily know or need to know the details of how we found these genes. We didn’t meet with a lot of resistance. We have a growing, expanding company that’s been going for the best part of eight years now, we have clients in over 30 countries and in all the major bloodstock regions in the world. And many of the top trainers and top owner-breeders in the world are using our genetic tests to inform their management practices. But, yes, it is a giant leap from the traditional way of doing things. The feedback that we get is that everybody who has used it has found some benefit from it because not always will they be able to tell from the pedigree page what genetics will tell them.  Rather than looking at the engine from outside the car, what we can do is open the hood and look inside the engine.

TDN: The discovery of the speed gene was a huge breakthrough. What’s on the drawing board now and what do you hope will be your next breakthrough?

EH: The speed gene is a single gene contributing to a specific trait, which is distance. We are able to now capture genetic information from all of the genes in the genome and package that information into predictions of a range of different traits, one of which is we can predict the horses that are most likely to be elite performers, we can make predictions about whether a horse is best suited to dirt or turf surfaces. We have been able to identify genes that contribute to the chances of a horse having a racecourse start as a 2-year-old versus as a 3-year-old. That’s a very interesting test because we found that the genes that are contributing to that aren’t necessarily physiological or metabolic genes but in fact genes that may be contributing to the temperament of the horse. What’s on the horizon? We’re now working toward the developments of tests for health traits of importance in the thoroughbred. You mentioned early on that there may be resistance within the industry to these performances tests. It’s probably worth pointing out that there is caution, particularly among industry bodies. The International Thoroughbred Breeders’ Federation last year established a policy on genomics and genetic testing and concluded that they saw no value in the widespread use of using genomics for performance testing. But they said there is potential value in the application of these tools when it comes to the development of tests for important health traits.

TDN: You just touched on this, but what would obviously be the biggest breakthrough would be your ability through your scientific tests to figure out whether or not the horse is likely to become an elite performer on the racetrack or not. At this point, prior to the horse going into the sales ring, can you look at its genes and DNA and make an accurate determination as to whether or not it is going to be a good race horse?

EH: We can do that. We don’t offer that at the sale because the tests we do are quite complicated and in the laboratory and are quite time consuming because we are assessing all of the genes, 20,000 genes in the genome. Because of the particular chemistry involved in that we are not able to offer that at the point of sale. But we have in the past tested yearlings in advance of the sales for clients to help inform their buying decisions. We hope in the future to develop the technology where we can have a situation where we have a stall side testing.

TDN: These tests, the ones that try to predict future success on the racetrack, how accurate have you found them to be?

EH: The speed gene test is extremely accurate. Depending on which region of the world you are talking about, 98% of the horses we say will fall into a particular category fall into that category. With the other tests, there is a different range in the accuracy of those. With the elite performer tests, if the individual is what we refer to as a Class 1 horse, then that individual has in the order of 2.5 times a greater chance of being an elite performer than a horse that is categorized as a Class 4 horse.

TDN: One of the best examples of how horses with the exact same pedigree can differ in their ability is Barbaro and his brothers. Barbaro was a great horse. He had four full-brothers and none of them were very successful. From a scientific standpoint, how is that possible?

EH: It’s absolutely fascinating. For such a long time, centuries, breeders have relied on pedigrees to inform them about the potential of a horse and how it will perform on the racetrack. If you are looking at the pedigrees of full-siblings those pedigree pages look exactly the same. But what they might have inherited from their parents can be very, very different. That’s because each individual only receives one copy of a chromosome from their sire and their dam and either one of those pairs of parental chromosomes can be passed down to the individual. That means there is a 50-50 chance of getting one or other pair of the parental chromosomes. Also, complicating the matter, is that when gametes are produced, that is the sperm and egg cells that go into making a foal, during that process there is something that goes on called recombination. What that does is it actually mixes up the genetic material from the grandparents, so it’s not exactly the same in the production of the gametes. The long and the short of that is no two individuals inherit the same DNA from their parents. They only have 50% sharing from their parents and then that’s diluted again from the next generation, worth a quarter, an eighth, a sixteenth and so on. Breeding is very much like a genetic lottery. You never know what is going to be passed down from the sire and the dam to that individual.

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