Submitted to: Plant and Animal Genome Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: November 1, 2005
Publication Date: January 14, 2006
Citation: Heaton, M.P., Leymaster, K.A., Clawson, M.L., Freking, B.A., Laegreid, W.W. 2006. A freely-available set of reference DNAs for genotyping the major scrapie susceptibility alleles in sheep [abstract]. Plant and Animal Genome Conference Proceedings. p. 239.
Scrapie is a fatal, transmissible disease affecting the central nervous system of sheep. Scrapie eradication is a national priority in many countries around the world, including the United States. Differences in genetic predisposition to scrapie have been correlated with variation in the amino acid sequence at positions 136, 154, and 171 of the host-encoded prion protein (PrP). Variation at these three positions gives rise to five common prion haplotypes (ARR, ARQ, ARH, AHQ, and VRQ). From these five haplotypes, there are 15 possible diplotypes (i.e., 15 combinations of any two haplotypes). Scoring these diplotypes with genotype assays is complicated by the presence of at least 19 polymorphic nucleotide sites in the region between codons 136 and 171. This report describes the identification of sheep from the US MARC flock representing each of the 15 possible diplotypes. DNA-rich tissues have been harvested from these animals for long-term use as quality controls in genotyping. The complete PRNP coding sequence has been determined for each of the 15 animals and deposited in GenBank (accession numbers AY907681-AY907694 and AY909542) to expedite assay development on a variety of genotyping platforms. Recently, DNA from a 16th animal with the ARK/ARQ diplotype was added to this reference set. These genetic resources (i.e., the MARC Sheep Scrapie Genotyping Panel version 16) are freely available by request to facilitate scrapie eradication in sheep.