Macedonian Veterinary Review

Original Scientific Article

Polymorphism of prion protein gene and evaluation on genetic risk for scrapie in three native and one introduced breed in the Republic of North Macedonia

Kocho Porchu *

Marija Zdravkovska ,

Dragoslav Kocevski ,

Zoran Tomislav Popovski

Mac Vet Rev 2026; 49 (2): i - ix

10.2478/macvetrev-2026-0023

Received: 16 February 2026

Received in revised form: 21 May 2026

Accepted: 07 July 2026

Available Online First: 05 August 2026

Published on: 15 October 2026

Correspondence: Kocho Porchu, kporcu@fznh.ukim.edu.mk

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Abstract

Transmissible spongiform encephalopathy in sheep is known as scrapie. Polymorphisms at codons 136, 154, and 171 of the prion protein (PRNP) gene are associated with resistance or susceptibility to the disease. Based on allele combinations, sheep are classified into five genetic risk groups. The aim of this study was to determine the distribution of PRNP gene polymorphisms and assess the genetic susceptibility to scrapie among native and introduced sheep breeds reared in North Macedonia. A total of 309 unrelated animals from three native Pramenka-type sheep breeds, Karakachanian (n=92), Ovchepolian (n=91), and Sharplaninian (n=34), and one introduced breed, Awassi (n=92), were genotyped. The Awassi and Sharplaninian breeds were dominated by the ARQ/ARQ genotype (R3). In Karakachanian sheep, the ARR/ARQ genotype (R2) was most frequent, while Ovchepolian sheep showed equal predominance of ARR/ARQ (R2) and ARQ/ARQ (R3). High-risk genotypes (R4 and R5) were detected only in the Ovchepolian and Sharplaninian breeds. The ARQ allele was the most frequent in Awassi (0.7609), Ovchepolian (0.4945), and Sharplaninian (0.5000), whereas the ARR allele predominated in Karakachanian sheep (0.5772). The VRQ allele was detected only in the Ovchepolian and Sharplaninian breeds. These findings demonstrate genetic differences among the studied sheep populations and provide valuable information for breeding strategies aimed at increasing resistance to scrapie while conserving breed diversity.

Keywords: scrapie, polymorphism, PrP genotype, Pramenka, Awassi

References

1. Prusiner, S.B. (1998). Prions. Proc Natl Acad Sci U.S.A. 95(23): 13363-13383.https://doi.org/10.1073/pnas.95.23.13363 PMid:9811807 PMCid:PMC33918
2. Goldmann, W. (2008). PrP genetics in ruminant transmissible spongiform encephalopathies. Vet Res. 39(4): 30. https://doi.org/10.1051/vetres:2008010 PMid:18284908
3. Hunter, N. (2007). Scrapie - uncertainties, biology and molecular approaches. Biochim Biophys Acta Mol Basis Dis. 1772(6): 619-628. https://doi.org/10.1016/j.bbadis.2007.04.007 PMid:17560089
4. Hunter, N., Moore L., Hosie B.D., Dingwall W.S., Greig, A. (1997). Association between natural scrapie and PrP genotype in a flock of Suffolk sheep in Scotland. Vet Rec. 140 (3): 59-63. https://doi.org/10.1136/vr.140.3.59 PMid:9023905
5. Clouscard, C., Beaudry, P., Elsen, J.M., Milan, D., Dussaucy, M., Bounneau, C., Schelcher, F., Chatelain, J., Launay, J.M., Laplanche, J.L. (1995). Different allelic effects of the codons 136 and 171 of the prion protein gene in sheep with natural scrapie. J Gen Virol. 76(8): 2097-2101. https://doi.org/10.1099/0022-1317-76-8-2097 PMid:7636494
6. Hunter, N., Goldmann, W., Smith, G., Hope, J. (1994). The association of a codon 136 PrP gene variant with the occurrence of natural scrapie. Arch Virol. 137, 171-177. https://doi.org/10.1007/BF01311184 PMid:7979991
7. Laplanche, J.L., Chatelain, J., Westaway, D., Thomas, S., Dussaucy, M., Brugere-Picoux, J., Launay, J.M. (1993). PrP polymorphisms associated with natural scrapie discovered by denaturing gradient gel electrophoresis. Genomics 15(1): 30-37. https://doi.org/10.1006/geno.1993.1006 PMid:8094373
8. Elsen, J.M., Barillet, F., Vu Tien Khang, J., Schelcher, F., Amigues, Y., Laplanche, J.L., Poivey, J.P., Eychenn, F. (1997). Genetics of susceptibility to scrapie in sheep: current research and perspectives [Génétique de la sensibilité à la tremblante ovine]. INRA Productions Animales. 10(2): 133-140. [In French]. https://doi.org/10.20870/productions-animales.1997.10.2.3989
9. Elsen, J.M., Amigues, Y., Schelcher, F., Ducrocq, V., Andreoletti, O., Eychenne, F., Khang, J.V., Poivey, J.P., Lantier, F., Laplanche, J.L. (1999). Genetic susceptibility and transmission factors in scrapie. Arch Virol. 144, 431 445. https://doi.org/10.1007/s007050050516 PMid:10226611
10. Thorgeirsdottir, S., Sigurdarson, S., Thorisson, H.M., Georgsson, G., Palsdottir, A. (1999). PrP polymorphism and natural scrapie in Icelandic sheep. J Gen Virol. 80(9): 2527-2534. https://doi.org/10.1099/0022-1317-80-9-2527 PMid:10501510
11. Smit, M.A., Cockett, N.E., Beever, J. E., Shay, T.L., Eng, S.L. (2002). Scrapie in sheep: A transmissible spongiform encephalopathy. Sheep Goat Res J. 17, 21-32.
12. Dawson, M., Hoinville, L.J., Hosie, B. D., Hunter, N. (1998). Guidance on the use of PrP genotyping as an aid to the control of clinical scrapie. Scrapie Information Group. Vet Rec. 142(23): 623-625.
13. European Commission. (2003). Commission Decision on scrapie breeding programmes. Official Journal of the European Union. 46, 2-12.
14. Epstein, H. (1985). The Awassi sheep with special reference to the improved dairy type. Rome: Food and Agriculture Organization of the United Nations
15. Porcu, K., Marković, B. (2006). Catalogue of West Balkan Pramenka sheep breed types. Skopje: Faculty of agricultural sciences and food
16. Porchu, K., Dzabirski V., Popovski, Z. (2020). DNA microsatellite informativeness, allele frequencies and their distribution in the genome of Macedonian autochthonous sheep populations. JAFES 74 (1): 1-10. https://doi.org/10.55302/JAFES20741001p
17. FAO. (2011). Molecular genetic characterization of animal genetic resources. FAO Animal Production and Health Guidelines. No. 9. Rome
18. Efremov, G.D., Dimovski, A., Plasheska-Karanfilska, D., Simjanovska, L., Shukarova, E., Koceva, S., Popovski, Z.T. (1998). Laboratory Manual, MASA-RCGEB
19. Moum, T., Olsaker, I., Hopp, P., Moldal, T., Valheim, M., Moum, T., Benestad, S.L. (2005). Polymorphisms at codons 141 and 154 in the ovine prion protein gene. J Gen Virol. 86(Pt 1): 231-235. https://doi.org/10.1099/vir.0.80437-0 PMid:15604451
20. Kalinowski, S.T., Taper, M.L., Marshall, T.C. (2007). Revising how the computer program CERVUS accommodates genotyping error increases success in paternity assignment. Mol Ecol. 16(5): 1099-1106. https://doi.org/10.1111/j.1365-294X.2007.03089.x PMid:17305863 PMCid:PMC10917668
21. Brandsma, J.H., Janss, L.L.G., Visscher, A.H. (2005). Association between PrP genotypes and performance traits in a experimental Dutch Texel herd. Livest Prod Sci. 95(1): 89-94. https://doi.org/10.1016/j.livprodsci.2004.12.011
22. Casellas, J., Caja, G., Bach, R., Francino, O., Piedrafita, J. (2007). Association analyses between the prion protein locus and production traits in Ripollesa sheep. J Anim Sci. 85(3): 592-597. https://doi.org/10.2527/jas.2006-308 PMid:17060422
23. Wiśniewska, E., Lühken, G., Mroczkowski, S., Erhardt, G. (2006). Prion protein gene polymorphisms in Polish Merino sheep. Arch Tierz. 49, Special Issue, 365-371. https://aab.copernicus.org/articles/AAB-Sonder heft-2006-2.pdf
24. Salaris, S., Casu, S., Carta, A. (2007). Relationship between the prion protein locus and milk yield in Sardinian sheep. J Anim Sci. 85(11): 2840-2845. https://doi.org/10.2527/jas.2006-610 PMid:17526657
25. Drögemüller, C., Leeb, T., Distl, O. (2001). PrP genotype frequencies in German breeding sheep. Vet Rec. 149(12): 349-352. https://doi.org/10.1136/vr.149.12.349 PMid:11594380
26. Gootwine, E., Abdulkhaliq, A., Jawasreh, K.I.Z., Valle Zárate, A. (2008). Screening for polymorphism at the prion protein (PrP) locus (PRNP) in Awassi and Assaf populations in. Small Rumin Res. 77(1): 80-83. https://doi.org/10.1016/j.smallrumres.2008.02.008
27. Babar,M.E.,Farid,A.,Benkel, B.F., Ahmad, J., Sajid, I.A., Imran, M., Hussain, T., Nadeem, A. (2008). Genetic variability at seven codons of the prion protein gene. J Genet. 87(2): 187-190. https://doi.org/10.1007/s12041-008-0029-z PMid:18776650
28. Meydan, H., Yüceer,B., Degirmenci, R., Özkan,M.M.,Yildiz,M.A.(2012). Prion protein gene polymorphism in Turkish sheep breeds. Virus Genes. 45(1): 169-175. https://doi.org/10.1007/s11262-012-0744-7 PMid:22528641
29. Zabavnik, J., Cotman, M., Pogačnik, M., Juntes, P. (2004). Scrapie-susceptibility-linked polymorphisms of the prion protein gene in Istrian Pramenka sheep. Slov Vet Res. 41(2): 83-88.
30. Cubric-Curik, V., Feligni, M., Ferencakovic, M., Dzidic, A., Salajpal, K., Ambriovic-Ristov, A., Cetkovic, H., Majhen, D., Curik, I. (2009): Sequence polymorphism of PrP exon 3 gene in Istrian and crossbred sheep. Ital J Anim Sci. 8(sup3): 86-88. https://doi.org/10.4081/ijas.2009.s3.86
31. Zecevic, E., Dokso, A., Kazic, A., Brka, M. (2015). Polymorphisms of ovine prion protein (PrP) gene in Pramenka sheepbreed population in Bosnia and Herzegovina. Turk J Vet Anim Sci. 39(5): 537-542. https://doi.org/10.3906/vet-1504-70
32. Ekateriniadou, L.V., Panagiotidis, C.H., Terzis, A., Ploumi, K., Triantafyllidis, A., Deligiannidis, P., Triantaphyllidis, C., Sklaviadis, T. (2007). Genotyping for PrP gene polymorphisms in rare Greek sheep breeds. Vet Rec. 160(6): 194-195. https://doi.org/10.1136/vr.160.6.194 PMid:17293579
33. Lühken, G., Buschmann, A,. Groschup, M.H., Erhardt, G., (2004). Prion protein allele A136 H154Q171 is associated with high susceptibility to scrapie in purebred and crossbred German Merinoland sheep. Arch Virol. 149(8): 1571-1580. https://doi.org/10.1007/s00705-004-0303-1 PMid:15290381
34. Baylis, M., Goldmann, W., Houston, F., Cairns, D., Chong, A., Ross, A., Smith, A., Hunter, N., McLean, A.R. (2002). Scrapie epidemic in a fully PrP-genotyped sheep flock. J Gen Virol. 83(Pt 11): 2907-2914. https://doi.org/10.1099/0022-1317-83-11-2907 PMid:12388827
35. Hunter, N., Cairns, D, Foster, J.D., Smith, G., Goldmann, W., Donnelly, K. (1997). Is scrapie solely a genetic disease? Nature. 386(6621): 137. https://doi.org/10.1038/386137a0 PMid:9062185

Copyright

©2026 Porchu K. This is an open-access article published under the terms of the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Conflict of Interest Statement

The authors declared that they have no financial or non-financial conflict of interest regarding authorship and publication of this article.

Citation Information

Macedonian Veterinary Review. Volume 49, Issue 2, Pages i-ix, e-ISSN 1857-7415, p-ISSN 1409-7621, DOI: https://doi.org/10.2478/macvetrev-2026-0023