Kdidi Samia, Yahyaoui Mohamed Habib, Conte Michela, Chiappini Barbara, Hammadi Mohamed, Khorchani Touhami, Vaccari Gabriele
Livestock and Wildlife Laboratory, Institut des Régions Arides, Université de Gabes, Route. El Djorf, Km 22.5, Medenine 4119, Tunisia.
Department of Food Safety, Nutrition and Veterinary Public Health, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
Animals (Basel). 2021 May 31;11(6):1635. doi: 10.3390/ani11061635.
Scrapie is a fatal prion disease. It belongs to transmissible spongiform encephalopathies (TSEs), and occurs in sheep and goats. Similarly, to ovine species, the prion protein gene ( plays a major role in conferring resistance or susceptibility to TSE in goats. This study assesses the variability of in native and crossed-breed goat populations raised in the Southeast of Tunisia and provides information on the distribution of haplotypes and genotypes in these goat populations. A total of 116 unrelated goats including 82 native and 34 crossed-breed goats were screened for polymorphisms using Sanger sequencing. Sequence analysis revealed 10 non-synonymous polymorphisms (G37V, M137I, R139S, I142M, H143R, N146D, R154H, R211Q, Q222K, and S240P), giving rise to 12 haplotypes and 23 genotypes. Moreover, four silent mutations were detected at codons 30, 42, 138, and 179; the former was reported for the first time in goat (nucleotide 60 c→t). Interestingly, the PrP variants associated with resistance (D146 and K222) or with a prolonged incubation time of goat to scrapie (M142, R143, H154, Q211) were absent or detected with low frequencies except for H154 variant, which is present with high frequency (1%, 1%, 4%, 0%, 88%, and 6%, respectively, for native goats, and 0%, 1%, 0%, 1%, 78%, and 1%, respectively, for crossed goats). The analysis of polymorphisms of goats raised in other regions of the country will be useful in getting a global view of genetic variability and the feasibility of goat breeding programs in Tunisia.
羊瘙痒症是一种致命的朊病毒病。它属于传染性海绵状脑病（TSEs），发生于绵羊和山羊。同样，与绵羊品种类似，朊病毒蛋白基因在赋予山羊对TSE的抗性或易感性方面起主要作用。本研究评估了突尼斯东南部饲养的本地和杂交山羊群体中该基因的变异性，并提供了这些山羊群体中该基因单倍型和基因型分布的信息。使用桑格测序法对总共116只无亲缘关系的山羊进行了该基因多态性筛查，其中包括82只本地山羊和34只杂交山羊。序列分析揭示了10个非同义多态性（G37V、M137I、R139S、I142M、H143R、N146D、R154H、R211Q、Q222K和S240P），产生了12种单倍型和23种基因型。此外，在密码子30、42、138和179处检测到四个沉默突变；其中第一个（核苷酸60 c→t）是首次在山羊中报道。有趣的是，与抗性相关的PrP变体（D146和K222）或与山羊对羊瘙痒症潜伏期延长相关的变体（M142、R143、H154、Q211）除了H154变体以高频存在外（本地山羊分别为1%、1%、4%、0%、88%和6%，杂交山羊分别为0%、1%、0%、1%、78%和1%），均不存在或检测到的频率较低。分析该国其他地区饲养的山羊的该基因多态性，将有助于全面了解该基因的遗传变异性以及突尼斯山羊育种计划的可行性。
