Italian Journal of Animal Science (Jan 2010)

Prion protein gene frequencies in three Sicilian dairy sheep populations

  • Santo Caracappa,
  • Pascal A. Oltenacu,
  • Baldassarre Portolano,
  • Marina Scimonelli,
  • Fabrizio Vitale,
  • Francesco Pinelli,
  • Johannes B.C.H.M. van Kaam,
  • Maria Vitale,
  • Raffaella Finocchiaro

DOI
https://doi.org/10.4081/ijas.2008.87
Journal volume & issue
Vol. 7, no. 1
pp. 87 – 94

Abstract

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The objective of this paper was to investigate the prion protein (PrP) genotype and haplotype frequencies in three Sicilian dairy sheep populations. The three populations were: (1) 1096 Valle del Belice animals, (2) 1143 Comisana animals, and (3) 1771 individuals from 5 flocks with scrapie outbreaks, in which the animals were crossbreds derived from indigenous Sicilian dairy breeds. PrP genotypes are described for the three codons 136 (Alanine or Valine; A, V), 154 (Histidine or Arginine; H, R), and 171 (Glutamine, Arginine or Histidine; Q, R, H) which represent polymorphisms known to be linked with scrapie susceptibility. The Valle del Belice haplotype frequencies were 32.3% ARR, 6.5% AHQ, 1.0% ARH, 58.8% ARQ, and 1.4% VRQ. The Comisana frequencies were 39.4% ARR, 2.9% AHQ, 2.9% ARH, 50.9% ARQ, and 3.9% VRQ. In the flocks with scrapie outbreaks the frequencies were 32.8% ARR, 2.4% AHQ, 1.7% ARH, 59.1% ARQ, and 3.9% VRQ. In all three populations ARQ and ARR were the most frequent haplotypes. Multiple generations of strong selection will be needed to fixate the most resistant ARR haplotype.

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