Statistical evaluation of scrapie susceptibility in some

Pubblicato su: SPVet.it - ISSN 1592-1581 (http://spvet.it/; http://indice.spvet.it); Numero 86/2014
34° International Society for Animal Genetics Conference
Xi’an, July 28th- August 1st 2014
Statistical evaluation of scrapie susceptibility in some Italian sheep breeds
Carla Sebastiani1 , Ludovica Curcio1,2 , Marcella Ciullo1 , Carmen Maresca1 , Annalisa Dettori1 , Emiliano Lasagna2, Massimo Biagetti1
1. Istituto Zooprofilattico Sperimentale dell’Umbria e delle Marche, Perugia, Italy; 2. Department of Agricultural, Food and Environmental Science, University of Perugia, Italy
INTRODUCTION
The aim of this study was to perform a statistical evaluation of PRNP allele and genotype frequencies of the sheep population of Umbria and
Marche regions in order to evaluate the probability to find genotypes susceptibles or resistant to scrapie in 8 italian sheep breeds: Sarda,
Merinizzata, Merinos, Bergamasca, Massese, Appenninica, Fabrianese and Comisana.
MATERIALS & METHODS
Allelic Discrimination by Real-time PCR
Farms
136
154
171.1
171.2
Blood
sampling
DNA
extraction
DNA from
different breeds
171.2
136
StepOne Plus Real-Time
PCR System
154
Statistical analysis
Odds Ratio (OR) with 95% confidence interval (CI) was calculated as a measure of association between breed and frequencies of
susceptible and resistant alleles and genotypes. Data with P-value ≤0.05 were considered statistically significant.
RESULTS
Analysis on the behavior of the breeds respect to ARR allele and susceptible genotypes based on OR calculation on
allele and genotype frequencies, respectively.
Probability to have a susceptible genotype
Probability to have ARR resistant allele
BREED
OR (CI 95%)
P-value
BREED
OR (CI 95%)
P-value
Sarda Vs other breeds
1,26 (1,20-1,32)
0,000
Sarda Vs other breeds
0,66 (0,62-0,72)
0,0000
Merinizzata Vs other breeds
0,64 (0,61-0,68)
0,000
Merinizzata Vs other breeds
1,76 (1,65-1,88)
0,0000
Bergamasca Vs other
breeds
0,85 (0,78-0,93)
0,000
Merinos Vs other breeds
0,79 (0,70-0,89)
0,0001
Merinos Vs other breeds
1,14 (1,05-1,24)
0,003
Bergamasca Vs other breeds
1,09 (0,97-1,22)
0,1555
Massese Vs other breeds
2,14 (1,94-2,36)
0,000
Massese Vs other breeds
0,34 (0,29-0,40)
0,0000
Fabrianese Vs other breeds
0,54 (0,42-0,68)
0,000
Fabrianese Vs other breeds
0,90 (0,66-1,23)
0,4838
Appenninica Vs other
breeds
1,09 (0,87-1,38)
0,440
Appenninica Vs other breeds
0,82 (0,58-1,17)
0,2566
Comisana Vs other breeds
2,29 (1,69-3,11)
0,000
Comisana Vs other breeds
0,31 (0,17-0,56)
0,0000
Five breeds had an higher probability to present ARR allele
respect to all other breeds (OR>1); in particular, Sarda,
Merinos, Massese, Comisana, and Appenninica. P-values were
statistically significant for all breeds except for Appenninica.
Sarda, Merinos, Massese and Comisana breeds show a lower
probability to have a sensitive genotype than other breeds
(OR<1). Fabrianese and Appenninica have OR<1, while
Bergamasca breed have OR>1, but P-values were not
statistically significant in both cases.
DISCUSSION AND CONCLUSION
The results of statistical analysis as a whole, demonstrate that Sarda, Comisana, Massese and Merinos breeds have a low probability to be
affected by scrapie than the other breeds analyzed and so they could be classifiable as resistant breeds. As regards to the other breeds, they
have a medium to high probability to be susceptible to scrapie.
This project was funded by the Italian Ministry of Health , RC IZSUM 08/2011
Stampato a cura dell'Unità Operativa di Supporto Biblioteca, Informazione, Editoria (2013).
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