Tobiano Gene Discoveries Mean Better Tests

Looking to breed for spots and have certainty about it?

Breeders trying to produce horses with tobiano coloring have a new tool, available through genetic research, to help them select their breeding stock.

Video: Dr. Brooks explains her research.

Dr. Brooks explains her research.

Video: Dr. Bailey explains the equine genome project.

Watch Dr. Bailey explain the genome project.

Tobiano is a common spotting pattern in horses, but up until this point the available tests to determine whether a horse could pass this pattern on to offspring weren’t always accurate. Samantha Brooks, PhD, postdoctoral fellow at the University of Kentucky’s Gluck Equine Research Center, recently completed a project that will result in an accurate test for this pattern.

Brooks looked at the chromosomes of tobiano horses and discovered a large rearrangement of the genes thought to be involved in the production of pigment.

"We’ve designed a DNA-based test that will enable us to look for this chromosome inversion and, therefore, predict which horses are going to have two copies of tobiano--known as homozygous--and are going to be true breeding, so breeders can select for animals that are going to give them the best production of spotted horses," she said. "This inversion so far, from our own testing as well as that of collaborators, is 100% associated with the tobiano gene, so that means that it’s going to be an excellent test."

The peer-reviewed paper on this study will appear in the December/January issue of Cytogenetic and Genome Research.

About the Author

Erin Ryder

Erin Ryder is a former news editor of The Horse: Your Guide To Equine Health Care.

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