Introduction - In sheep, susceptibility/resistance to scrapie is mainly associated to the polymorphisms of PRNP gene at codons 136, 154 and 171. Five alleles are usually present (ARR, ARQ, ARH, AHQ, VRQ) and they have a crucial role in terms of incubation period and/or susceptibility to scrapie. Aim - In this study we analysed PrP genotypes obtained from different sheep breeds reared in central Italy (Umbria and Marche regions) during last seven years in order to gain knowledge of the allelic and genotypic frequencies and of the correlation between genotype, breed and productive purpose. Materials and methods - A total of 21152 animals belonging to half-breeds and 8 purebreeds (Merinizzata, Bergamasca, Merinos, Fabrianese, Appenninica, Sarda, Massese and Comisana) were genotyped by Real time PCR. Results and discussion - The ARQ and ARR were predominant alleles. The frequencies of the ARR/ARQ, ARQ/ARQ, ARR/ARR genotypes overlay with other studies. Considering the correlation between susceptible genotypes and productive purpose, meat breeds had a higher number of susceptible genotypes than dairy and dual purpose breeds. Conclusion - The results showed that Sarda, Comisana, Massese and Merinos breeds have a lower probability to be affected by scrapie than the other breeds analysed and so they could be classifiable as breeds with a good level of genetic resistance. As regards to the other breeds, they have a medium to high level of genetic susceptibility to scrapie.
A study on PrP genotype frequencies in meat and dairy sheep breeds reared in Umbria and Marche regions
CURCIO, LUDOVICA;LASAGNA, Emiliano;
2015
Abstract
Introduction - In sheep, susceptibility/resistance to scrapie is mainly associated to the polymorphisms of PRNP gene at codons 136, 154 and 171. Five alleles are usually present (ARR, ARQ, ARH, AHQ, VRQ) and they have a crucial role in terms of incubation period and/or susceptibility to scrapie. Aim - In this study we analysed PrP genotypes obtained from different sheep breeds reared in central Italy (Umbria and Marche regions) during last seven years in order to gain knowledge of the allelic and genotypic frequencies and of the correlation between genotype, breed and productive purpose. Materials and methods - A total of 21152 animals belonging to half-breeds and 8 purebreeds (Merinizzata, Bergamasca, Merinos, Fabrianese, Appenninica, Sarda, Massese and Comisana) were genotyped by Real time PCR. Results and discussion - The ARQ and ARR were predominant alleles. The frequencies of the ARR/ARQ, ARQ/ARQ, ARR/ARR genotypes overlay with other studies. Considering the correlation between susceptible genotypes and productive purpose, meat breeds had a higher number of susceptible genotypes than dairy and dual purpose breeds. Conclusion - The results showed that Sarda, Comisana, Massese and Merinos breeds have a lower probability to be affected by scrapie than the other breeds analysed and so they could be classifiable as breeds with a good level of genetic resistance. As regards to the other breeds, they have a medium to high level of genetic susceptibility to scrapie.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
