title: PrP genotype frequencies and risk evaluation for scrapie in dairy sheep breeds from southern Italy.
abstract: Concerns regarding scrapie in sheep breeding have increased in the last few decades. The present study was carried out in dairy sheep breeds from southern Italy. In order to find breeding animals resistant to scrapie, the PrP genes of 1,205 animals from entire flocks of dairy native Apulian Leccese and Altamurana breeds, and Sicilian Comisana breed, were analysed for polymorphisms at codons 136, 154, and 171 related to scrapie resistance/susceptibility. The Altamurana breed was considered as two populations (Alt-Cav and Alt-Cra-Zoe), based on presumed cross-breeding. A total of five alleles and ten different genotypes were found. The ARQ allele was predominant for all breeds followed by ARR, the most resistant allele to scrapie, which was highly prevalent in Comisana (50%) and in native Alt-Cav (42.4%). The VRQ allele, associated with the highest susceptibility to scrapie, was detected at not negligeable levels in allocthonous Comisana (3.5%), at a low frequency (0.2%) in native Leccese and Alt-Cra-Zoe, while it was absent in Alt-Cav. The frequencies of PrP genotypes with a very low susceptibility risk to scrapie (R1) was higher in Comisana and Alt-Cav. The most susceptible genotype, ARQ/VRQ, was found only in Comisana. Within the Altamurana breed, there were notable differences between Alt-Cav and Alt-Cra-Zoe sheep. The Alt-Cav was characterised by the absence of VRQ and AHQ alleles and by the higher frequency of the ARR/ARR genotype (18.7%). Breeding programs, mainly in endangered breeds such as Altamurana, should be conducted gradually, combining resistance to scrapie, maintenance of genetic variability, and production.
authors.affiliation: Department of Scienze Agro-Ambientali e Territoriali, Via G. Amendola 165/A, 70126 Bari, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Martemucci
authors.affiliation: Institute of Zootechnics, Università Cattolica del S. Cuore, Via Emilia Parmense 84, 29122 Piacenza, Italy.
authors.forename: Daniela
authors.initials: D
authors.lastname: Iamartino
authors.affiliation: Dipartimento Qualità Agroalimentare, Via Tomassetti 9, 00161 Roma, Italy.
authors.forename: Michele
authors.initials: M
authors.lastname: Blasi
authors.affiliation: Department of Scienze Agro-Ambientali e Territoriali, Via G. Amendola 165/A, 70126 Bari, Italy. Electronic address: angelagabriella.dalessandro@uniba.it.
authors.forename: Angela Gabriella
authors.initials: AG
authors.lastname: D'Alessandro
mesh_terms: D000818:Animals; D001947:Breeding; D003612:Dairying; D020022:Genetic Predisposition to Disease / Q000453:epidemiology; D005838:Genotype; D007558:Italy / Q000453:epidemiology; D011110:Polymorphism, Genetic; D011328:Prions / Q000235:genetics*; D018570:Risk Assessment; D012608:Scrapie / Q000453:epidemiology* / Q000209:etiology / Q000235:genetics; D012756:Sheep
chemical_list: D011328:Prions
keywords: Genetic variability; Prion protein (PrP) gene; Scrapie susceptibility; Sheep