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United States Department of Agriculture

Agricultural Research Service

2008 Annual Report

1a.Objectives (from AD-416)
1) Characterize variation in the bovine prion gene complex in U.S. cattle populations. 2) Associate prion gene complex haplotypes with susceptibility to BSE.

1b.Approach (from AD-416)
The project will take a population-based approach employing principles of genetic epidemiology. First, we will characterize polymorphisms and haplotype structure in the prion gene complex in U.S. and U.K. cattle populations. Then we will utilize this comprehensive knowledge of genetic variation to analyze BSE case-control sets for association with specific alleles. We hypothesize that alleles of the bovine prion gene complex are associated with increased susceptibility to BSE.

3.Progress Report

During the last year,.
1)genetic variation within the prion gene of atypical BSE cases was tested for an association with atypical BSE,.
2)a large prevalence study was conducted on U.S. cattle to determine the frequency of a prion gene variant suspected as having been the genetic cause of a U.S. atypical BSE case, and.
3)methods were developed for characterizing variation throughout the bovine prion gene. Additionally, a study was conducted in sheep which tested genetic variation in the prion gene for an association with scrapie resistance. Scrapie is an ovine transmissible spongiform encephalopathy. The sheep used in the study were historically regarded as susceptible to scrapie (ARQ).

National Program 103 - Animal Health; Program Components - Problem Statements 2C: Genetic and Biological Determinants of Disease Susceptibility - Mucosal Diseases of Livestock and Poultry and 8: Countermeasures to Prevent and Control Transmissible Spongiform Encephalopathies - Scrapie and Bovine Spongiform Encephalopathy (BSE)

This research was conducted through the U.S. Meat Animal Research Center with significant contributions from collaborators in other ARS locations, U.S. universities, and research organizations in Canada and France. The ADODR has been in constant contact with collaborators through email and phone conference calls.

Review Publications
Clawson, M.L., Richt, J., Baron, T., Biacabe, A., Czub, S., Heaton, M.P., Smith, T.P., Laegreid, W.W. 2008. Association of a bovine prion gene haplotype with atypical BSE. PLoS One [serial online]. 3(3):e1830. Available:

Heaton, M.P., Keele, J.W., Harhay, G.P., Richt, J., Koohmaraie, M., Wheeler, T.L., Shackelford, S.D., Casas, E., King, D.A., Sonstegard, T.S., Van Tassell, C.P., Neibergs, H.L., Chase, C.C., Kalbfleisch, T.S., Smith, T.P., Clawson, M.L., Laegreid, W.W. 2008. Prevalence of the prion gene E211K variant in U.S. cattle. BioMed Central (BMC) Veterinary Research [journal online]. 4:25. Available: (

Clawson, M.L., Heaton, M.P., Keele, J.W., Smith, T.P., Harhay, G.P., Richt, J., Laegreid, W.W. 2008. A sequencing strategy for identifying variation throughout the prion gene of BSE-affected cattle. BMC Research Notes [journal online]. 1:32. Available:

Laegreid, W.W., Clawson, M.L., Heaton, M.P., Green, B.T., Orourke, K.I., Knowles Jr, D.P. 2008. Scrapie resistance in ARQ sheep. Journal of Virology. 82(20):10318-10320. Available: DOI:10.1128/JVI.00710-08.

Last Modified: 4/20/2015
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