The Nubian ibex (Capra nubiana) is a wild goat species that inhabits the Sahara and Arabian deserts and is adapted to extreme ambient temperatures, intense solar radiation, and scarcity of food and water resources. To investigate desert adaptation, we explored the possible role of copy number variations (CNVs) in the evolution of Capra species with a specific focus on the environment of Capra nubiana. CNVs are structural genomic variations that have been implicated in phenotypic differences between species and could play a role in species adaptation. CNVs were inferred from Capra nubiana sequence data relative to the domestic goat reference genome using read-depth approach. We identified 191 CNVs overlapping with protein-coding genes mainly involved in biological processes such as innate immune response, xenobiotic metabolisms, and energy metabolisms. We found copy number variable genes involved in defense response to viral infections (Cluster of Differentiation 48, UL16 binding protein 3, Natural Killer Group 2D ligand 1-like, and Interferon-induced transmembrane protein 3), possibly suggesting their roles in Nubian ibex adaptations to viral infections. Additionally, we found copy number variable xenobiotic metabolism genes (carboxylesterase 1, Cytochrome P450 2D6, Glutathione S-transferase Mu 4, and UDP Glucuronosyltransferase-2B7), which are probably an adaptation of Nubian ibex to desert diets that are rich in plant secondary metabolites. Collectively, this study's results advance our understanding of CNVs and their possible roles in the adaptation of Nubian ibex to its environment. The copy number variable genes identified in Nubian ibex could be considered as subjects for further functional characterizations.

努比亚羱羊（ Capra nubiana ）是一种生活在撒哈拉沙漠和阿拉伯沙漠的野山羊，适应极端的环境温度、强烈的太阳辐射以及食物和水资源的稀缺。为了研究沙漠适应，我们探索了拷贝数变异（CNV）在卡普拉物种进化中的可能作用，特别关注卡普拉努比亚纳的环境。 CNV 是结构基因组变异，与物种之间的表型差异有关，并且可能在物种适应中发挥作用。使用读取深度方法从相对于国内山羊参考基因组的Capra nubiana序列数据推断出 CNV。我们鉴定了 191 个与蛋白质编码基因重叠的 CNV，主要涉及先天免疫反应、外源代谢和能量代谢等生物过程。我们发现拷贝数可变基因参与对病毒感染的防御反应（分化簇 48、UL16 结合蛋白 3、自然杀伤组 2D 配体 1 样和干扰素诱导的跨膜蛋白 3），这可能表明它们在努比亚羱羊适应中的作用到病毒感染。此外，我们还发现了拷贝数可变的外源代谢基因（羧酸酯酶 1、细胞色素 P450 2D6、谷胱甘肽 S-转移酶 Mu 4 和 UDP 葡萄糖醛酸基转移酶-2B7），这些基因可能是努比亚野山羊对富含植物次生代谢物的沙漠饮食的适应。总的来说，这项研究的结果增进了我们对 CNV 及其在努比亚羱羊适应环境中可能发挥的作用的理解。在努比亚羱羊中鉴定出的拷贝数可变基因可被视为进一步功能表征的对象。