Researchers Sequence Horse Genome

COLLEGE STATION, TX – A group of international scientists – including three researchers from Texas A&M University – have completed for the first time the genome sequence of the horse, which may open doors for improved breeding, disease treatment and even enhanced performance traits.

Horse Genome

Dr. Loren Skow (left), Dr. Terje Raudsepp and Dr. Bhanu Chowdhary participated in the project to sequence the participated in the horse genome.

The multi-national team of 60 researchers has published its work on the project in the current issue of “Science” magazine. Funding groups include the National Human Genome Research Institute, the Dorothy Russell Havemeyer Foundation, the Volkswagen Foundation, the Morris Animal Foundation and the European Science Foundation.

Texas A&M researchers Loren Skow, Bhanu Chowdhary and Terje Raudsepp, all associated with the College of Veterinary Medicine & Biomedical Sciences, participated in the horse genome project, completed at Broad Institute in Cambridge, Mass. The group took DNA from a single Thoroughbred mare for the sequencing project.

The researchers say that with more than 90 hereditary conditions such as infertility, muscle disorders, allergies and inflammatory diseases, sequencing the horse has much to offer as a model species.

“One thing we learned from the project is that the structure of the chromosomes in the horse is similar to other mammals, including humans,” Skow says.

“The information we collect from this will be helpful down the road in work with genetic mutations and identifying certain disorders, possibly even in developing strategies to increase disease resistance.”

Skow says that in general terms, horses and related donkeys and zebras have chromosome structures that evolved rapidly compared to other species. “This work gives us a chance to look closely at the entire evolutionary process of chromosome formation and diversification using the horse as a model,” he adds.

“It also lets us look at the human-animal model closer at the level of individual genes. If a gene has mutated in a horse, it may help us identify a similar process and how it relates to a clinical problem in humans. We may be able to point to that gene as the problem and work from there. About one-half of the horse genome sequence is very similar in organization to that of humans. So it gives us a human application, but it can also work vice versa – it may give us more knowledge about genetic problems in horses, too.”

The project has particular interest in Texas: the state is home to more than 1 million horses, the most of any state, and the horse industry has an economic impact of more than $5 billion, with 96,000 jobs directly related to the equine industry. About 300,000 Texans own at least one horse, studies show, and Texas leads the nation in the number of registered American Quarter Horses, American Paint Horses, Appaloosa Horses and American Miniature Horses.

Chowdhary, associate dean for research and graduate studies in the College of Veterinary Medicine & Biomedical Sciences and one of the researchers involved in the project, notes that the Texas A&M team “helped to provide the background map of the horse genome.

“With the availability of the whole genome sequence, we have entered into a new era in equine research. The sequence has already led to the development of novel tools and resources that have initiated studies previously considered difficult or impossible.

“While the study of single traits or diseases will be significantly enhanced, it will now be possible to study complex traits governed by several genes, and perform association studies between traits important to the industry and variations observed in the genome.”

Chowdhary adds, “Advanced analysis can now be initiated to understand the molecular basis of disease resistance, reproduction, fertility, etc. Studies have been initiated on the molecular basis pathogenesis of important diseases. This reflects a major shift that has been possible only due to the complete genome sequence of the horse. There will definitely be more exciting research that will follow soon.”

Raudsepp says that completing the sequence “is exciting for what it tells us about the equine genome now, and what it can tell us years from now. We anticipate that the sequence assembly will trigger the development of new tools to study the horse genome in ways never envisioned earlier. It should significantly improve the speed and accuracy to determine the underlying genetics of simple and complex traits in horses.

“There is still a lot of work to be done, but this is a huge step for the scientific community,” she notes.


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