Frequencies of PrP gene haplotypes in British sheep flocks and the implications for breeding programmes.
OBJECTIVE
To analyse the frequencies of prion (PrP) gene haplotypes in UK sheep flocks and evaluate their relevance to transmissible spongiform encephalopathies (TSEs) and TSE resistance breeding programmes in sheep.


RESULTS
Genomic DNA isolated from sheep blood was PCR amplified for the coding region of the PrP gene and then sequenced. This study has analysed the sequence of PrP between codons 110 and 245 in 6287 ARQ haplotypes revealing a total of eight variant sequences, which represent a higher than expected 41% of all ARQ haplotypes. The additional PrP gene dimorphisms were M112T, L141F, M137T, H143R, H151C, P168L, Q175E and P241S.


CONCLUSIONS
The results do not suggest a correlation between the occurrence of a specific ARQ haplotype and the scrapie disease status of a flock. The ARQ haplotype variability appears to be different in the UK sheep flocks compared with sheep flocks from outside the UK.


CONCLUSIONS
Additional PrP dimorphisms may impact on the methodologies used for standard PrP genotyping in sheep breeding programmes. Some of these polymorphisms were found with significant frequencies in the UK sheep flocks and should therefore be considered in breeding programmes.
Goldmann
W
W
Neuropathogenesis Unit, Institute for Animal Health, Ogston Building, West Mains Road, Edinburgh EH9 3JF, Scotland, UK. wilfred.goldmann@bbsrc.ac.uk
Baylis
M
M
Chihota
C
C
Stevenson
E
E
Hunter
N
N
D000595:Amino Acid Sequence; D000818:Animals; D001947:Breeding / Q000379:methods*; D003062:Codon / Q000235:genetics; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D006239:Haplotypes / Q000235:genetics; D011110:Polymorphism, Genetic / Q000235:genetics; D011328:Prions / Q000235:genetics*; D012608:Scrapie / Q000235:genetics*; D012756:Sheep; D006113:United Kingdom
D003062:Codon; D011328:Prions