SMALL RUMINANT RESEARCH, cilt.111, sa.1-3, ss.16-22, 2013 (SCI-Expanded)
Scrapie, a fatal transmissible spongiform encephalopathy (TSE), occurs in two phenotypes;
classical and atypical. The aim of this study was to assess the genetic risk and identify the
PRNP polymorphisms for atypical scrapie in a total of 1110 healthy sheep from 18 Turkish
native sheep breeds. There were 10 alleles and 23 genotypes observed based on codons 136,
141, 154 and 171 of PRNP gene. The ALRQ allele was predominant for all breeds. The AFRQ
allele, associated with the susceptibility to atypical scrapie, was detected in only I'vesi.
The other susceptible allele, ALHQ, was found at low frequencies in Akkaraman, Kangal
Akkaraman, Güneykaraman, Kıvırcık, Sakız, Da^glıc¸ and Gökc¸ eada breeds. Generally, the
ALRQ/ALRQ genotype, which is resistant to atypical scrapie, was predominant in all breeds.
Among the most susceptible genotypes to atypical scrapie, only ALHQ/ALHQ was found in
this study. In addition, the ARR/ARR genotype, which has been reported in lots of atypical
scrapie positive sheep from various countries, was detected in almost all Turkish native
sheep breeds. According to our results, it is propounded that the susceptibility to atypical
scrapie increased from eastern to western part of Turkey. Although it seems that Turkish
native sheep breeds are safe from atypical scrapie, the occurrence of susceptible genotypes
should be taken into consideration.