The future is now?

Source:  The future is now?    Tag:  pedigree genetics
Easily the most interesting thing that flickered across my laptop screen over the last week was this item from the Irish Times. It may also have been the most significant, but it is impossible to tell at this point.

Emmeline Hill is both a horsewoman and a geneticist. Her grandfather, Charmian Hill, owned the immortal jumper Dawn Run, who won 23 of 37 races in the 1980s and remains the only horse to have won the two biggest races at the Cheltenham festival, the Champion Hurdle (1984) and the Cheltenham Gold Cup Steeplechase (1986). Dawn Run is still regarded as the best mare in the history of English National Hunt racing.

Emmeline Hill's primary occupation over the last decade or more, however, has been as a researcher into the genetics of the Thoroughbred. She began her career as a student of and assistant to Patrick Cunningham, the famed geneticist at Trinity College Dublin, one of the first geneticists to publish peer-reviewed research on Thoroughbred genetics. Cunningham's research showed, among other things, that certain founding fathers of the breed--Herod, Eclipse, Godolphin Arabian--each contribute between 13% and 17% of the genes of modern Thoroughbreds. He also showed that racing ability is about 35% heritable, and that the ability of the modern racehorse, as measured by Timeform ratings, is still increasing at a rate predicted by that measure of heritability.

Hill has built upon and markedly expanded the genetic research Cunningham began. Hill led the pioneering study of Mitochondrial DNA patterns in Thoroughbreds published in the August 2002 issue of Animal Genetics that showed that a few hallowed Thoroughbred female lines do not trace to the foundation mare legitimized by the General Stud Book. You can read Patricia Erigero's excellent summary (originally published in Thoroughbred Times) of Hill's mtDNA work at Erigero's and Anne Peters's Thoroughbred Heritage website, which also includes a link to Hill's original Animal Genetics article.

Not surprisingly, far more geneticists work on human genetics than Thoroughbred genetics, and by the mid-naughts, those researchers had discovered more than 140 human genes connected with fitness and athletic performance. Hill began work on cross-referencing those genes with the equine genome and researching their relationship to performance in Thoroughbreds by sequencing DNA of a sizable sample of Thoroughbreds compared to non-Thoroughbreds.

The result of that study was published in the online journal PLOS1 (Public Library of Science) in June 2009, and publicized in the Irish Times.

As published Hill's study shows that, yes, Thoroughbred genetics is different from non-Thoroughbrd genetics in ways that are known to contribute to muscle mass, aerobic and anaerobic energy usage, lung capacity, etc., etc. Surprise, surprise! And, no, I don't mean to belittle this important research, but as far as I can see, that particular paper simply confirmed what any thoughtful horseman already knew--the Thoroughbred possesses better genes for athletic performance than the non-Thoroughbred.

What I am trying to puzzle out now is exactly how this research translates to Hill's and Jim Bolger's new venture, Equinome, which plans to test DNA of prospective sires and dams and prospective racehorses and make recommendations for breeders and buyers. Those recommendations are clearly meant to be based on Hill's research, but nowhere in what has been published is there any information on variations within the population of Thoroughbreds she tested for the study . In fact there are only two sentences in the PLSO1 paper that presage Equinome's proposed services: "We have identified a number of candidate performance genes that may contain variants that could distinguish elite racehorses from members of the population with less genetic potential for success. Revealing such polymorphisms may aid in the early selection of young Thoroughbreds in the multi-billion dollar global Thoroughbred industry."

It is quite possible, even probable, that Hill and colleagues have, in fact, found variations in the Thoroughbred population used in their study, or in larger populations not included in the published study, but, if so, that data has not been published. Therefore, it is impossible at this point to evaluate the validity of the approach. From the information presented in the PLOS1 paper, one could obviously devise a test to tell a Thoroughbred from a non-Thoroughbred, but then, again, we already have that...it's called the Stud Book. From a scientific point of view, it is clear that this could be a fruitful avenue of further research....but that research, if it exists, has not been published.

All we know about the research Hill's and Bolger's tool is based on is this sentence from last week's Irish Time's article: "The test is based on research by Hill into athletic performance traits in horses conducted and the project was supported by the Irish Thoroughbred Breeders Association which provided the required DNA samples from elite racehorses." Well, that is certainly interesting, but it tells us virtually nothing about whether or not this might be a useful tool.

As I said in the beginning, I'm just trying to figure this out. Nothing that I've written above should be taken as a put down of Hill's research or even of the potential usefulness of the tool (though the Irish Times's rather breathless adulation is perhaps a valid target). I hold a graduate degree in a scientific field (statistical experimental psychology), and I have always approached Thoroughbred breeding as a quasi-scientific endeavor, applying the scientific approach to pedigrees as much as our tools allow. I'm not about to denigrate anyone doing real science on Thoroughbred genetics. Instead, I heartily applaud Hill's research and hunger for more. And I accept that in our capitalist world, the line between science and commercialism is essentially non-existent. In fact, University College Dublin's Nova unit, specifically designed to commercialize UCD's research, awarded Hill a grant to help fund Equinome. But I still think the scientific data should be published first and I wonder what business the ITBA has at least indirectly funding this commercial venture as well.

Do elite Thoroughbreds possess different genes in critical locations than the non-elite population? There can be no doubt whatsoever that this is true. Does Equinome have a test that can tell you whether or not a particular Thoroughbred possesses some of those critical genes? Clearly they believe they do.

If they do, then they will forever change the process of buying and selling horses. Mr. Horse Breeder, do you think it's difficult to sell your less attractive, less well-bred horses now? Mr. Pinhooker, do you find it almost impossible to market a horse that cannot work fast? Wait until everyone demands a DNA test before they will buy your product. The individuals targeted no doubt would change, but the gap between the favored few and the rest? If you think it's bad now, you ain't seen nothing yet.

It was rumored at the time that the Maktoum family cooperated with and perhaps helped fund Hill's mtDNA study. It will be interesting over the next few years to see who pays Equinome for their services and whether their record as buyers improves.