In this context, the work of Dr Emmeline Hill from the UCD School of Agriculture, Food Science & Veterinary Medicine, is essential. Dr Hill is seeking to identify those genetic factors that are important in race-winning horses. Researchers have found that up to 30 per cent of the performance of champion horses is determined by their genetics, so if the genetic factors for success can be nailed down, the Irish horse industry should gain some competitive advantage over its rivals.
The origins of the thoroughbred horse date back 400 years to the time of the Tudor and Stewart kings of England, who developed a strong interest in racing horses. These English kings wanted to improve on their horses’ racing ability and began to introduce Arab types, which were bred with local running hobby horses. Later in 1791, the breeding of horses became a more scientific process with the establishment of the world’s first thoroughbred stud book by an Englishman called James Weatherby. From that point on, the exact lineage of all thoroughbreds was put down on paper.
Today, Ireland is home to 10 per cent of the world’s thoroughbreds. Hill, who is from Wexford and is from a horse breeding and racing background, is a member of the tiny community of equine genetics researchers in the world. She estimates that there are perhaps 30 in total around the globe. She is a very promising young researcher, something which was underlined when she was awarded (along with another UCD researcher Dr Jens Erik Neilsen) a President of Ireland Young Researcher Award from Science Foundation Ireland. The award means that she can receive funding of up to €1.2 million over a five year period. The idea of the award and the accompanying funding is to provide significant and stable financial support to top tier young investigators at a level and over a time duration that will enable them to develop careers as internationally recognised researchers.
The goal of Dr Hill’s project - to identify genetic factors that might be associated with enhanced performance of thoroughbred racehorses - is a big task. Researchers have found in the human there are 120 genes associated with performance and fitness traits, and the story is likely to be something similar in elite racehorses. The first thing to do is to undergo a genomic scan to identify the regions of the genome (the entire DNA material of the horse) that have undergone selection for increased performance in the elite horse. The second aspect of the work is the use of so called microarrays. This technique involves looking at the expression of thousands of genes simultaneously, and measuring the level of messenger RNA, the precursor to protein, that is present in the cell. These techniques allow researchers to determine gene activity in the cell at any given time.
Dr Hill wants to take a look at the different genes that are expressed in the thoroughbred when it is resting, against the thoroughbred post-exercise. She also wants to look at the expression of genes after a four-week period of training, during which time there is a change in what are called the fast and slow twitch muscle cells. There is a commercial horse gene chip that has most of the horse’s genes on it. This horse chip means that Dr Hill can examine up to 3,000 horse genes all at once, at given times during training or resting.
“The use of these so-called micro-arrays has revolutionized biomedical science,” said Dr Hill. “Now we can look at the expression of hundreds or thousands of genes all at once. In the past we would have had to look at them one by one. For instance, we can look at the muscle tissue of horses and see what genes are being expressed at the end of a race when a horse has been pushed to the limit of its performance. The elite horses are those that perform optimally in low oxygen conditions”. Since tissue samples are hard to come by, it is necessary to set up an in-vitro model replicating such low oxygen conditions as exist at the end of a race. Dr Cormac Taylor, an SFI investigator at the UCD Conway Institute, cultures cells in normal oxygen conditions and in hypoxic (low oxygen) conditions, and these systems will be used by Hill. She will monitor the expression of genes in normal oxygen and low oxygen conditions. There is an adaptive response to low oxygen conditions that is regulated by HIF-1, a master gene that triggers a cascade of other genes involved in processes such as glycolysis (energy provision), erythropoiesis (red blood cell generation), vasodilatation (expansion of blood vessels) etc. It may be, for instance, that the muscle of the thoroughbred horse has a greater capacity to adapt to low oxygen conditions than that of the carthorse, for example.
This research could be very important to the thoroughbred horse industry here in Ireland. If the genetic factors that determine a potential champion are identified early on, then the trainer and owner need not go to the time and expense of developing a thoroughbred that is simply not going to ‘cut the mustard’ at the top level.
“The reason that a thoroughbred is successful has to do with genetics and the environment,” said Hill. “Management, training and nutrition are also important. However, Paddy Cunningham at TCD found that 30 per cent of the variation in performance in the equine thoroughbred is due to genetics, and that is what we want to unravel”. Professor Maurice Boland, Principal of the UCD College of Life Sciences commented, “It is a great pleasure to facilitate Dr Hill's research programme. Her work complements the established research programme in Animal Genomics in the Area of Animal Science.”