Yan Chaochao, Wu Wei, Dong Wenqi, Zhu Bicheng, Chang Jiang, Lv Yunyun, Yang Shilong, Li Jia-Tang
CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization and Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
Innovation (Camb). 2022 Aug 1;3(5):100295. doi: 10.1016/j.xinn.2022.100295. eCollection 2022 Sep 13.
Animals have evolved sophisticated temperature-sensing systems and mechanisms to detect and respond to ambient temperature changes. As a relict species endemic to the Qinghai-Tibet Plateau, hot-spring snake () survived the dramatic changes in climate that occurred during plateau uplift and ice ages, providing an excellent opportunity to explore the evolution of temperature sensation in ectotherms. Based on distributional information and behavioral experiments, we found that prefer hot-spring habitats and respond more quickly to warmth than other two snakes, suggesting that may evolve an efficient thermal-sensing system. Using high-quality chromosome-level assembly and comparative genomic analysis, we identified cold acclimation genes experiencing convergent acceleration in high-altitude lineages. We also discovered significant evolutionary changes in thermosensation- and thermoregulation-related genes, including the transient receptor potential (TRP) channels. Among these genes, TRPA1 exhibited three species-specific amino acid replacements, which differed from those found in infrared imaging snakes, implying different temperature-sensing molecular strategies. Based on laser-heating experiments, the -specific mutations in resulted in an increase in heat-induced opening probability and thermal sensitivity of the ion channels under the same degree of temperature stimulation, which may help the organism respond to temperature changes more quickly. These results provide insight into the genetic mechanisms underpinning the evolution of temperature-sensing strategies in ectotherms as well as genetic evidence of temperature acclimation in this group.
动物已经进化出复杂的温度传感系统和机制来检测并响应环境温度变化。作为青藏高原特有的孑遗物种，温泉蛇（Thermophis）在高原隆升和冰河时代发生的剧烈气候变化中存活下来，为探索变温动物温度感知的进化提供了绝佳机会。基于分布信息和行为实验，我们发现温泉蛇偏好温泉栖息地，且比其他两种蛇对温暖的反应更快，这表明温泉蛇可能进化出了高效的热传感系统。通过高质量的染色体水平组装和比较基因组分析，我们鉴定出在高海拔谱系中经历趋同加速的冷适应基因。我们还发现了与温度感知和体温调节相关基因的显著进化变化，包括瞬时受体电位（TRP）通道。在这些基因中，TRPA1表现出三个物种特异性的氨基酸替换，这与在红外成像蛇中发现的不同，暗示了不同的温度传感分子策略。基于激光加热实验，温泉蛇特有的TRPA1突变导致在相同程度的温度刺激下离子通道热诱导开放概率和热敏感性增加，这可能有助于生物体更快地响应温度变化。这些结果为变温动物温度传感策略进化的遗传机制提供了见解，也为该类群温度适应的遗传证据提供了依据。
