Key Laboratory of Animal Genetics and Breeding on Tibetan Plateau, Ministry of Agriculture and Rural Affairs, Lanzhou Institute of Husbandry and Pharmaceutical Sciences, Chinese Academy of Agricultural Sciences, Lanzhou 730050, China.
Sheep Breeding Engineering Technology Research Center of Chinese Academy of Agricultural Sciences, Lanzhou 730050, China.
Int J Mol Sci. 2024 Nov 19;25(22):12394. doi: 10.3390/ijms252212394.
In recent years, research has gradually uncovered the mechanisms of animal adaptation to hypoxic conditions in different altitude environments, particularly at the genomic level. However, past genomic studies on high-altitude adaptation have often not delved deeply into the differences between varying altitude levels. This study conducted whole-genome sequencing on 60 Tibetan sheep (Medium Altitude Group (MA): 20 Tao sheep (TS) at 2887 m, High Altitude Group (HA): 20 OuLa sheep (OL) at 3501 m, and Ultra-High Altitude Group (UA): 20 AWang sheep (AW) at 4643 m) from different regions of the Tibetan Plateau in China to assess their responses under varying conditions. Population genetic structure analysis revealed that the three groups are genetically independent, but the TS and OL groups have experienced gene flow with other northern Chinese sheep due to geographical factors. Selection signal analysis identified , , , , , , , and as genes associated with ultra-high-altitude hypoxia adaptation, while , , , , and were linked to high-altitude hypoxia adaptation. Functional analysis showed that ultra-high-altitude adaptation genes tend to influence physiological mechanisms directly affecting oxygen uptake, such as lung development, angiogenesis, and red blood cell formation. In contrast, high-altitude adaptation genes are more inclined to regulate mitochondrial DNA replication, iron homeostasis, and calcium signaling pathways to maintain cellular function. Additionally, the functions of shared genes further support the adaptive capacity of Tibetan sheep across a broad geographic range, indicating that these genes offer significant selective advantages in coping with oxygen scarcity. In summary, this study not only reveals the genetic basis of Tibetan sheep adaptation to different altitudinal conditions but also highlights the differences in gene regulation between ultra-high- and high-altitude adaptations. These findings offer new insights into the adaptive evolution of animals in extreme environments and provide a reference for exploring adaptation mechanisms in other species under hypoxic conditions.
近年来，研究逐渐揭示了动物在不同海拔环境中适应低氧条件的机制，特别是在基因组水平上。然而，过去关于高海拔适应的基因组研究往往没有深入探讨不同海拔高度之间的差异。本研究对来自中国青藏高原不同地区的 60 只藏羊（中海拔组（MA）：20 只洮羊（TS）在 2887m，高海拔组（HA）：20 只欧拉羊（OL）在 3501m，超高海拔组（UA）：20 只阿旺羊（AW）在 4643m）进行了全基因组测序，以评估它们在不同条件下的反应。群体遗传结构分析表明，这三个群体在遗传上是独立的，但由于地理因素，TS 和 OL 群体与其他中国北方绵羊有基因流动。选择信号分析鉴定出、、、、、、、和作为与超高海拔低氧适应相关的基因，而、、、、和与高海拔低氧适应相关。功能分析表明，超高海拔适应基因倾向于直接影响氧气摄取的生理机制，如肺发育、血管生成和红细胞形成。相比之下，高海拔适应基因更倾向于调节线粒体 DNA 复制、铁稳态和钙信号通路以维持细胞功能。此外，共享基因的功能进一步支持了藏羊在广泛地理范围内的适应能力，表明这些基因在应对缺氧方面具有显著的选择优势。综上所述，本研究不仅揭示了藏羊适应不同海拔条件的遗传基础，还突出了超高海拔和高海拔适应之间基因调控的差异。这些发现为动物在极端环境中的适应性进化提供了新的见解，并为探索其他物种在低氧条件下的适应机制提供了参考。
