Based on the relatively homogeneous origin of the sheep breeds in Morocco that originate mainly from Iberia, it is highly relevant to address the question of how these very diverse sheep populations differentiated from each other. The Mountains of the High Atlas and Middle Atlas are expected to constitute North–South and West–East geographical barriers, respectively, which could have shaped the history of the differentiation of sheep breeds. The aim of this study was to test this hypothesis by considering the genetic structure and the spatial distribution of five major breeds (Sardi, Timahdite, Beni Guil, Boujaad and D’man) and one minor breed (Blanche de Montagne), by analysing the mtDNA control region, using 30 individuals per breed. Phylogenetic and network analyses did not indicate any clear separation among the studied breeds and discriminant component principal analysis showed some overlap between them, which indicates a common genetic background. The calculated pairwise FST values and Nei’s genetic distances revealed that most breeds showed a moderate genetic differentiation. The lowest and highest degrees of differentiation were retrieved in the Beni Guil and Boujaad breeds, respectively. Analysis of molecular variance (AMOVA) indicated that more than 95% of the genetic diversity occurs within individuals, while between- and within-population variabilities represent only 1.332% and 2.881%, respectively. Isolation-by-distance, spatial Principal Component Analysis (sPCA), and spatial AMOVA analyses evidenced clear examples of geographical structuration among the breeds, both between and within breeds. However, several enigmatic relationships remain, which suggest the occurrence of complex events leading to breed differentiation. The approaches used here resulted in a convergent view on the hypothetic events that could have led to the progressive differentiation between the Moroccan breeds. The major split seems to be linked to the West–East barrier of the Middle Atlas, whereas the influence of the High Atlas is less obvious and incompletely resolved. The study of additional breeds that have settled near the High Atlas should clarify the relationships between the breeds of the West part of the country, in spite of their small population size.

中文翻译：

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摩洛哥的绵羊品种如何区分？遗传结构和地理分布模式

基于摩洛哥绵羊品种的相对同质起源，主要起源于伊比利亚，因此解决这些非常多样化的绵羊种群如何相互区分的问题非常重要。预计高阿特拉斯山脉和中阿特拉斯山脉将分别构成南北和西-东地理屏障，这可能塑造了绵羊品种分化的历史。本研究的目的是通过分析五个主要品种（Sardi、Timahdite、Beni Guil、Boujaad 和 D'man）和一个次要品种（Blanche de Montagne）的遗传结构和空间分布来检验这一假设。 mtDNA 控制区，每个品种使用 30 个个体。系统发育和网络分析没有表明研究品种之间有任何明显的分离，判别成分主分析表明它们之间存在一些重叠，这表明它们具有共同的遗传背景。计算的成对 FST 值和 Nei 的遗传距离表明，大多数品种表现出中等的遗传分化。分别在 Beni Guil 和 Boujaad 品种中检索到最低和最高的分化程度。分子方差分析 (AMOVA) 表明，超过 95% 的遗传多样性发生在个体内部，而种群间和种群内的变异分别仅代表 1.332% 和 2.881%。距离隔离、空间主成分分析 (sPCA) 和空间 AMOVA 分析证明了品种间地理结构的清晰例子，品种之间和品种内。然而，仍然存在一些神秘的关系，这表明导致品种分化的复杂事件的发生。此处使用的方法导致对可能导致摩洛哥品种之间逐渐分化的假设事件的看法趋于一致。主要分裂似乎与中阿特拉斯的东西障碍有关，而高阿特拉斯的影响不那么明显且未完全解决。对在高阿特拉斯附近定居的其他品种的研究应该澄清该国西部地区品种之间的关系，尽管它们的人口规模很小。此处使用的方法导致对可能导致摩洛哥品种之间逐渐分化的假设事件的看法趋于一致。主要分裂似乎与中阿特拉斯的东西障碍有关，而高阿特拉斯的影响不那么明显且未完全解决。对在高阿特拉斯附近定居的其他品种的研究应该澄清该国西部地区品种之间的关系，尽管它们的人口规模很小。此处使用的方法导致对可能导致摩洛哥品种之间逐渐分化的假设事件的看法趋于一致。主要分裂似乎与中阿特拉斯的东西障碍有关，而高阿特拉斯的影响不那么明显且未完全解决。对在高阿特拉斯附近定居的其他品种的研究应该澄清该国西部地区品种之间的关系，尽管它们的人口规模很小。