Dr. Molly McCue of the University of Minnesota will be doing a webcast on July 20, 2011, the fifth in a series titled "Equine Genetics: A New Diagnostic Resource for Horse Owners.” The webcast is funded by a grant from the U.S. Department of Agriculture’s National Research Initiative.
Within the last 20 years, there has been an explosion of information on medical genetics that has greatly influenced human medicine. Most of these advances have been the result of a multimillion dollar investment in the human genome project that has sequenced all 3 billion base pairs of DNA and located an estimated 20,000 to 25,000 human genes on their respective chromosomes.
Advances in the technology used to sequence the human genome, and the decrease cost of genome sequencing, allowed a draft sequence of the horse genome to be produced. In the last four years this had lead to several key discoveries in equine genetics including the identification of new disease mutations, as well as, for the first time, the identification of genes underlying performance traits.
In the past, the world of equine genetic mutations was limited to coat colors and a handful of simple disease traits. For the majority of these mutations, a horse’s phenotype (or outward physical appearance) could be easily predicted from its genotype (the presence/absence of a mutation and the number of copies). Advances in genetics in horses, humans, and other species have lead to the realization that very few genetic traits are simple.
Most genetic diseases in humans are considered complex traits, meaning that they are influenced by one or more genes as well as the environment or other factors. The classic examples of complex genetic traits in people are the BRCA I and II susceptibility genes for breast cancer. Having one of these mutations does not guarantee that an individual will develop breast cancer. Other factors like gender and lifestyle choices are also important. Having the BRCA I or II mutation means that you are at increased risk for developing breast cancer. Knowing that an individual is at higher risk means that physicians can follow more aggressive early detection plans such as more frequent mammograms starting at an earlier age.
Advances in equine genetics are now allowing researchers to look for the same types of genetic risk factors in horses. For example, identifying the underlying genetic factors involved in the development of Equine Metabolic Syndrome (EMS) and associated laminitis. Identifying these genetic factors will allow for the development of genetic tests so owners and veterinarians can manage horses at high risk for EMS and laminitis. These high risk horses can then be managed differently from an early age with the goal of preventing EMS and laminitis.
While this increase in information in equine genetic is exciting, it also comes with some confusion. The complex interplay of multiple genes and other factors can make interpretation of genetic tests difficult. In this webinar, we will define complex traits and the goals of research and genetic testing, and how these results can be used to improve horse health. Furthermore, we will work through examples of equine genetic traits that are influenced by more than one gene and other factors such as environment.
Presenter Information: Dr. Molly McCue DVM, MS, PhD is an assistant professor in veterinary population medicine at the University of Minnesota College of Veterinary Medicine.