Brooks Equine Genetics Research Lab
Size Study
Description
Morphometrics And QTL Mapping Of Skeletal Variation In The Horse (aka “The Size Study”) - in collaboration with Dr. Nathan Sutter.
What makes your horse different from the horse in the stall over? Why doesn’t a Kentucky Derby contender walk like a Budweiser Clydesdale? Why don’t either of them look like Thumbelina, the current Guinness World Record holder for the world’s smallest living horse? The domestic horse comes in a range of sizes, shapes, and temperaments from the tiny American Miniature Horse to the massive draft breeds, humans have historically bred horses for both aesthetic and functional qualities. For the horse in particular, size and conformation have been two major driving forces for the development of the diverse breeds we see today. Horses have been bred to pull carts, jump fences, or run a mile-long race. When horse breeders look to improve these abilities in their stock, they are often selecting for changes in genes, called alleles, that affect body size and conformation.
Allele variation in several genes has already been shown to contribute to body size diversity in many species. As body size genes affect fundamental developmental processes such as cell growth, they can sometimes be correlated to other diseases, like the tumor growth seen in cancer. By exploring the genetics of body size in the horse, we hope to improve not only the livelihood of the horse population, but also better understand the genetics of diseases that affect all mammals, including humans. Furthermore, when we investigate body size genes, we will look for genes that contribute to breed-specific traits in the horse, especially conformation and skeletal qualities valued by breeders.
Body size and complex disease genes can only be identified through the DNA analysis of hundreds of horses from many different breeds and types. Your horse has a unique pattern of genes that, when compared to other horses, can give a clue to the genes and interactions that control body size. DNA can be isolated from almost any cell in the body, and in this case the skin tags from a routine tail hair pull will supply more than enough DNA for us to analyze. In addition to this hair sample, our study will require a profile photo, 3-generation pedigree, and 35 measurements of your horse. These measurements will help us judge the size and conformation of your horse relative to other horses, and are an essential component of our study. The entire process should take only about 15 minutes of your time per horse. All information is strictly confidential.
Every individual horse is an important contribution to our study and another step towards improving the quality of life for both horses and humans.
Does this study sound familiar? You may have seen information about this study in some of your favorite equine publications such as:
The Blood-Horse, No. 24, June 13, 2009, p.2111
The Horse, June 2009, p.18
Equus, July 2009, p.12
Practical Horseman, July 2009, p.72
Horse and Rider, August 2009
Horse Measurement Instructions
Before you begin, make sure your horse is standing on even ground. Measurements should be recorded in inches. Please do not attempt to measure an unwilling horse. We appreciate your contribution to our equine genetics research.