Invasive Species Compendium

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Abstract

Genotyping of German sheep with respect to scrapie susceptibility.

Abstract

This study aimed to show the prion protein (PrP) genotype distribution in diagnosed German scrapie cases, and in 487 sheep from 5 important German breeds: Merinoland, Schwarzköpfiges Fleischschaf [German Blackheaded Mutton], Texel, Suffolk and East Friesian milk sheep. All sampled animals belonged to pedigree flocks. Texel sheep carried PrPVRQ alleles (valine, arginine and glutamine at allele positions 136, 154 and 171 respectively) but this was almost completely absent from the other breeds. Merinoland sheep carried PrPARQ (alanine, arginine, glutamine) in a homozygous (41%) or heterozygous (50%) form, East Friesians carried PrPARQ (85%) and PrPAHQ (H=histidine, 64%) with 49% of sheep being heterozygous for both alleles. Only 6% of this breed carried the rare PrPARR, and none were homozygous. German Blackheaded Mutton and Suffolk carried homozygous PrPARQ (9 and 6% respectively); PrPARR homozygous was carried by 48% of Suffolk and 43% of German Blackheaded Mutton, and heterozygous (with PrPARQ) was carried by both breeds at 45%. In combination with PrPVRQ, Suffolk carried PrPARR at 1% and German Blackheaded Mutton at 2%. Almost all scrapie disease animals were PrPARQ homozygous, with only one sheep having a PrPARQ/PrPARR genotype. It is concluded that the German sheep population should be considered sufficiently susceptible to sustain scrapie endemically and appropriate control measures should be undertaken.