大量研究表明,摩洛哥的本土绵羊品种在遗传上是同质的,在他们主要居住的具有挑战性的恶劣气候条件下,对他们的生存构成风险。通过纯合性(ROH)的镜头来了解遗传同质性背后的遗传,我们分析了五个本地绵羊品种的全基因组序列(BeniGuil,OuledDjellal,D\'男人,萨迪,Timahdite和混合)。主成分的结果,掺合料,Fst,和邻居连接树分析一致显示出同质的遗传结构。该结构的特征在于纯合性(ROH)片段的平均长度为1.83Mb,具有有限数量的长ROH段(24-48Mb和>48Mb)。最常见的ROH片段是1-6Mb的那些。纯合性的最显著区域(ROH岛)主要在两条染色体中观察到,即Chr1和Chr5。具体来说,ROH群岛仅在Chr1的OuledDjellal品种中发现,而Chr5在所有品种中都展示了ROH群岛。采用ROH岛和iHS技术的分析来检测Chr1和Chr5上的选择特征。结果表明,Chr5具有较高的同质性,在所有品种中都发现了相同的基因。相比之下,Chr1显示了品种之间的一些遗传变异。在Chr5上鉴定的基因包括SLC39A1,IL23A,CAST,负责免疫应答的IL5、IL13和IL4,而在Chr1上鉴定的基因包括SOD1、SLAMF9、RTP4、CLDN1和PRKAA2。ROH区段分布和有效种群大小模式表明,所研究品种的遗传一致性是250至300代前发生的事件的结果。这项研究不仅有助于了解不同品种的ROH分布,还有助于设计和实施摩洛哥本土绵羊的育种和保护策略。未来的研究,纳入更广泛的样本量,并利用pangenome作为参考,建议进一步阐明这些品种的基因组景观和适应机制。
Numerous studies have indicated that Morocco\'s indigenous sheep breeds are genetically homogenous, posing a risk to their survival in the challenging harsh climate conditions where they predominantly inhabit. To understand the genetic behind genetic homogeneity through the lens of runs of homozygosity (
ROH), we analyzed the whole genome sequences of five indigenous sheep breeds (Beni Guil, Ouled Djellal, D\'man, Sardi, Timahdite and Admixed).The results from principal component, admixture, Fst, and neighbour joining tree analyses consistently showed a homogenous genetic structure. This structure was characterized by an average length of 1.83 Mb for runs of homozygosity (ROH) segments, with a limited number of long
ROH segments (24-48 Mb and > 48 Mb). The most common
ROH segments were those ranging from 1-6 Mb. The most significant regions of homozygosity (ROH Islands) were mostly observed in two chromosomes, namely Chr1 and Chr5. Specifically,
ROH Islands were exclusively discovered in the Ouled Djellal breed on Chr1, whereas Chr5 exhibited
ROH Islands in all breeds. The analysis of ROH Island and iHS technique was employed to detect signatures of selection on Chr1 and Chr5. The results indicate that Chr5 had a high level of homogeneity, with the same genes being discovered across all breeds. In contrast, Chr1 displays some genetic variances between breeds. Genes identified on Chr5 included SLC39A1, IL23A, CAST, IL5, IL13, and IL4 which are responsible for immune response while genes identified on Chr1 include SOD1, SLAMF9, RTP4, CLDN1, and PRKAA2. ROH segment profile and effective population sizes patterns suggests that the genetic uniformity of studied breeds is the outcome of events that transpired between 250 and 300 generations ago. This research not only contributes to the understanding of ROH distribution across breeds but helps design and implement native sheep breeding and conservation strategies in Morocco. Future research, incorporating a broader sample size and utilizing the pangenome for reference, is recommended to further elucidate these breeds\' genomic landscapes and adaptive mechanisms.