Selection, both natural and artificial, leaves patterns on the genome during domestication of animals and leads to changes in allele frequencies among populations. Detecting genomic regions influenced by selection in livestock may assist in understanding the processes involved in genome evolution and discovering genomic regions related to traits of economic and ecological interests. In the current study, genetic diversity analyses were conducted on 34,206 quality-filtered SNP positions from 450 individuals in 15 sheep breeds, including six indigenous breeds from the Middle East, namely Iranian Balouchi, Afshari, Moghani, Qezel, Karakas and Norduz, and nine breeds from Europe, namely East Friesian Sheep, Ile de France, Mourerous, Romane, Swiss Mirror, Spaelsau, Suffolk, Comisana and Engadine Red Sheep. The SNP genotype data generated by the Illumina OvineSNP50 Genotyping BeadChip array were used in this analysis. We applied two complementary statistical analyses, F_ST (fixation index) and xp-EHH (cross-population extended haplotype homozygosity), to detect selection signatures in Middle Eastern and European sheep populations. F_ST and xp-EHH detected 629 and 256 genes indicating signatures of selection, respectively. Genomic regions identified using F_ST and xp-EHH contained the CIDEA, HHATL, MGST1, FADS1, RTL1 and DGKG genes, which were reported earlier to influence a number of economic traits. Both F_ST and xp-EHH approaches identified 60 shared genes as the signatures of selection, including four candidate genes (NT5E, ADA2, C8A and C8B) that were enriched for two significant Gene Ontology (GO) terms associated with the adenosine metabolic procedure. Knowledge about the candidate genomic regions under selective pressure in sheep breeds may facilitate identification of the underlying genes and enhance our understanding on these genes role in local adaptation.

中文翻译：

---

中东和欧洲绵羊品种的选择特征研究

自然和人工选择在动物驯化过程中会在基因组上留下模式，并导致种群间等位基因频率的变化。检测受家畜选择影响的基因组区域可能有助于理解基因组进化过程和发现与经济和生态利益特征相关的基因组区域。在当前的研究中，对来自 15 个绵羊品种的 450 个个体的 34,206 个经过质量过滤的 SNP 位置进行了遗传多样性分析，其中包括来自中东的六个本土品种，即伊朗 Balouchi、Afshari、Moghani、Qezel、Karakas 和 Norduz，以及九个来自欧洲的品种，即东弗里西亚羊、法兰西岛、穆勒鲁斯、罗曼、瑞士镜、斯帕索、萨福克、科米萨纳和恩加丁红羊。该分析使用了 Illumina OvineSNP50 基因分型 BeadChip 阵列生成的 SNP 基因型数据。我们应用了两个互补的统计分析，F_ST（固定指数）和 xp-EHH（跨种群扩展单倍型纯合性），用于检测中东和欧洲绵羊种群的选择特征。F _ST和 xp-EHH 分别检测到 629 个和 256 个指示选择特征的基因。使用 F _ST和 xp-EHH鉴定的基因组区域包含 CIDEA、HHATL、MGST1、FADS1、RTL1 和 DGKG 基因，这些基因早先被报道会影响许多经济性状。两个 F _ST和 xp-EHH 方法确定了 60 个共享基因作为选择特征，包括四个候选基因（NT5E、ADA2、C8A 和 C8B），这些基因丰富了与腺苷代谢过程相关的两个重要基因本体论 (GO) 术语。了解绵羊品种在选择压力下的候选基因组区域可能有助于识别潜在基因并增强我们对这些基因在局部适应中的作用的理解。