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  • Author or Editor: Yueying Cao x
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Abstract

Objective

To develop new and improved tests to detect alleles at codons 136 and 171 of the ovine prion protein locus and to evaluate the frequency of these alleles.

Animals

159 Suffolk sheep belonging to 3 flocks.

Procedure

Polymerase chain reaction (PCR) analysis that contained diagnostic restriction site variation for each allele were developed for the relevant gene regions. Alleles were determined by analyzing DNA isolated from buccal swab specimens or blood samples.

Results

At codon 136, frequencies of the alanine and valine alleles were found to be 97 and 3%, respectively. At codon 171, frequencies of the glutamine, arginine, and histidine alleles were found to be 57, 41, and 2%, respectively.

Conclusions

Little variation was detected in codon 136, whereas noteworthy variation was found in codon 171; > 40% of the alleles at this locus coded for glutamine. Because the glutamine allele at codon 171 confers susceptibility to scrapie, reduction of its frequency is of importance to management of sheep flocks.

Clinical Relevance

Genotyping of sheep, using the tests reported here, should facilitate selective breeding programs designed to decrease the risk of scrapie. (Am J Vet Res 1999;60:884–887)

Free access
in American Journal of Veterinary Research

Abstract

Objective

To identify a DNA marker for the copper toxicosis (CT) locus in Bedlington Terriers (BT).

Animals

77 BT, of which 25 were affected. Diagnosis of affected or unaffected with CT was made in all cases by quantitative copper determinations on liver biopsy samples by use of established criteria.

Procedure

BT pedigrees segregating for CT were identified. Linkage studies were carried out using polymorphic microsatellite markers developed for the canine genome in these pedigrees. DNA was isolated from blood samples of pedigree members. Polymerase chain reaction was used to amplify and type alleles at 213 microsatellite loci in each dog, and findings were subjected to linkage analysis.

Results

One microsatellite marker was identified to be closely linked to CT with logarithm of odds score of 5.96 at a recombination fraction of zero.

Conclusions

Using the linked marker, it has become possible to distinguish affected, homozygous normal, and carrier dogs in some BT pedigrees.

Clinical Relevance

In informative pedigrees where the marker is variable in the parents, it is possible to identify which dogs will require anticopper therapy and provide breeders with sound scientific advice about breeding strategies. (Am J Vet Res 1997;58:23–27)

Free access
in American Journal of Veterinary Research