A critical set of genes linked to successful racehorses have been identified by a team of researchers which could allow breeders to pinpoint the next horse racing champion.
Scientists compared the genomes of thoroughbred, Arabian and Mongolian racehorses with horses bred for other sports and leisure.
They found a set of beneficial genes that show clear advantages in muscle, metabolism and neurobiology.
However, not all horses within a racing breed have an advantageous gene version, so scientists say the findings will be useful to identify the most suitable horses for racing.
The research was carried out by scientists from Asia, Europe, North America and the Irish equine science company Plusvital.
The study, published in Communications Biology, an open access journal from Nature, involved the collection of hair samples from 100 horses owned by the champion Ajnai Sharga Horse Racing Team at their breeding farm in Khentii province, Mongolia, the birthplace of Genghis Khan.
Using the DNA from these Mongolian racing horses, along with thoroughbred and racing Arabian horses, the scientists compared the genomes with 21 other non-racing breeds, such as Clydesdale, Connemara pony, Hanoverian, Morgan, Norwegian Fjord, Paint, Shetland and Shire, identifying seven essential genes for racing.
Among the top genes was NTM, which functions in brain development and influences learning and memory. This gene was selected during the horse domestication process, and in thoroughbred racehorses influences whether a horse ever races.
“Since the discovery of the ‘speed gene’ in 2009, we have generated genetic data for thousands of thoroughbreds and horses from other breeds,” said University College Dublin Professor Emmeline Hill, lead scientist on the project and chief science officer at Plusvital.
“This is the first time this set of genes has been linked to the success of racing breeds. Two of the genes were previously identified for performance in thoroughbreds and Arabians, but the approach we took was to ask what genes were common to all racing breeds and different from non-racing breeds.
“The very large number of horse breeds developed over the last hundreds of years all over the world have been carefully shaped by selective breeding for different traits desired by breeders. This has led to tall horses, small horses, powerful draft horses, useful riding horses and fast racing horses.
“We have discovered a set of genes common to racing horses, but not all horses within a racing breed have the advantageous gene version, so these findings will be useful to identify the most suitable individuals within a breed for racing or for breeding.”
UCD Professor David MacHugh co-authored the research. He said that racing is a “multifactorial trait”, meaning that management and training having a considerable influence on the success of a racehorse.
However, he said that the study provides “good evidence for major-effect genes shaping the racing trait in horse populations”.
Dr Haige Han, another project collaborator and first author of the paper, said: “Testing these variants in new sets of hundreds of horses from racing and non-racing breeds identified seven essential genes for racing.
“These genes have roles in muscle, metabolism, and neurobiological functions, and are central to racing ability among horse breeds.”
The researchers used expression data from the skeletal muscle of thoroughbred horses to investigate if the genes they had identified were involved in the muscle response to exercise and training.
“By integrating these two different data sets we fine-tuned the list of racing genes to those that were most biologically relevant to racing,” said Ms Hill.
“One of these genes was MYLK2 which is required for muscle contraction. In humans, MYLK2 is associated with exercise-induced muscle damage.”
