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Equine genetic markers

 

The objective of this project is to develop an equine genome  map that can be used to find and eliminate equine disease genes through selective breeding. The importance of genetic factors in a number of relatively common equine diseases is now coming to light. We are currently developing gene-specific sequence-tagged sites (STSs), a type of DNA marker, that will cover most or all of the horse chromosomes, and we are testing the hypothesis that sufficient genetic variability lies within the STS regions to allow them to be used directly to map disease genes.

 

 

Our research goals

We are working on a project to expand the sequence information in the equine genome map. We are developing gene-specific sequence-tagged sites (STSs), a type of DNA marker, that will cover most or all of the horse chromosomes, and we are testing the hypothesis that sufficient genetic variability lies within the STS regions to allow them to be used directly to map equine disease genes. In collaboration with Dr. Patrick Venta, we are testing universal mammalian STS polymerase chain reaction primer sets developed for the canine gene project in pools of horse DNAs. DNA is obtained from blood samples without causing significant discomfort to the subjects. The development of these equine mapping tools will lead to a decreased prevalence of equine disease-conferring genes and will ultimately increase the health of the horse population.

Figure 1: Fluorescently-labeled genomic DNA sequence. Each colored peak indicates a nucleotide (black = G; green = A; blue = C; red = T). Series of nucleotides determine the nature of the amino acid sequence to be constructed.

                                                     

 

Figure 2:  A radiography gel from the manual DNA sequencing of the horse albumin gene using the Pool and Sequence method. The sequencing ladder on the left is from a single horse and the ladder on the right is from a pool of ten horses. An arrow points to the position of a single nucleotide polymorphism (SNP) on the left, and the identical position in the single, control horse.

Significance

The development and application of equine molecular tools will aid the research of inherited diseases in the horse. Ultimately, this information can be used to find and eliminate equine disease genes through selective breeding.

 

Principle Investigator: Susan Ewart, DVM, PhD

Co-Investigators: Patrick Venta, PhD, Michigan State University, East Lansing, MI

 

Relevant publications

Brouillette JA, Andrew JR, Venta PJ. Estimate of nucleotide diversity in dogs with a pool-and-sequence method. Mamm Genome. 2000 Dec;11(12):1079-86.

Caetano AR, Shiue YL, Lyons LA, O'Brien SJ, Laughlin TF, Bowling AT, Murray JD. A comparative gene map of the horse (Equus caballus). Genome Res. Dec 9(12):1239-49; 1999.

Shubitowski DM, Venta PJ, Douglass CL, Zhou RX, Ewart, SL. Polymorphism identification within 50 equine gene-specific sequence tagged sites.  Anim Genet. Apr;32(2):78-88. 2001.

Venta PJ, Brouillette JA, Yuzbasiyan-Gurkan V, Brewer GJ. Gene-specific universal mammalian sequence-tagged sites: application to the canine genome. Biochem Genet 34(7-8):321-41; 1996.

 

Funding sources

Ewart SL, Venta PJ. Equine gene-specific sequence-tagged sites. MSU College of Veterinary Medicine Genetic Research Fund.