Filistin yerli koyun ırklarında prion protein kodlama geni polimorfizmlerinin analizi

Abstract

Prion protein kodlama geni (PRNP) koyunlarda klasik scrapie duyarlılığıyla ilişkilendirilen genetik lokusdur. Genin 136, 154 ve 171. kodonlarındaki ARQ ve VRQ allellerinin scrapie duyarlılığıyla, ARR allelinin ise scrapie dirençliliğiyle ilgili olduğu bilinmektedir. Bu çalışmanın amacı, scrapieye karşı genetik direncin belirlenmesi için Filistinli yerli koyun ırklarının genotiplendirilmesidir. Çalışmada, İvesi ve Assaf ırklarından, 38 sağlıklı ve rastgele seçilmiş koyun örnekleri kullanılmıştır. Koyun kan örneklerinden DNA izole edilmiş, PZR amplifikasyonu yapılmış ve sekans analizi gerçekleştirilmiştir. Prion protein kodlama geninde, ARQ, ARR, ARH, AHQ, ARL ve VRQ allelleri ve ARR/ARQ, ARQ/ARQ, ARQ/ARL, ARH/ARQ, ARH/ARL, AHQ/ARQ ve ARQ/VRQ genotipleri belirlenmiştir. Her iki ırkta da baskın olan ARQ alleli 0.76 ile en yüksek frekansta bulunurken, az görülen ARL alleli ise her iki ırkta da düşük frekanslarda belirlenmiştir. Ayrıca PRNP geninin farklı kodonlarında iki farklı polimorfizm (V12I ve L23H) tanımlanmıştır. Sonuçlar genotiplerin çoğunluğunun 3.risk grubuna dahil olduğunu göstermektedir. Assaf ve İvesi ırklarında dirençli allel sıklığını arttırmak için ARR/ARR koyunlarının yaygınlaştırılması önerilmektedir.

Keywords

• Assaf,Filistin,İvesi,PRNP,scrapie

Analysis of Prion Protein Coding Gene Polymorphisms in Palestinian Native Sheep Breeds

Abstract

Prion protein coding gene (PRNP) is the genetic locus correlated with the greatest impact on classical scrapie susceptibility in sheep. At codons 136, 154, and 171 of PRNP alanine/arginine/glutamine (ARQ) and valine/arginine/glutamine (VRQ) haplotypes, in turn, are related to susceptibility to classical scrapie while alanine/arginine/arginine ARR haplotype is correlated with resistance. The aim of the present study was to genotype the Palestinian native sheep breeds for detection of genetic resistance. A total of 38 healthy sheep from Awassi and Assaf breeds were randomly sampled. Genomic DNA was isolated from blood samples. After PCR amplification and DNA sequencing, ARQ, ARR, ARH, AHQ, ARL and VRQ alleles and ARR/ARQ, ARQ/ARQ, ARQ/ARL, ARH/ARQ, ARH/ARL, AHQ/ARQ and ARQ/VRQ genotypes were detected in PRNP gene. ARQ allele was found as a predominant allele in this study with the frequency of 0.76 for Awassi and Assaf breeds while the uncommon allele ARL was identified at low frequencies in both breeds. In addition, two different polymorphisms were recognized (V12I and L23H) at different codons of PRNP. Results have indicated that most of the genotypes belong to risk group 3. The careful dissemination of ARR/ARR sheep is suggested to increase resistant allele frequencies in Assaf and Awassi breeds.

Keywords

• Assaf,Awassi,Palestinian,PRNP,Scrapie

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