极端碱性环境中硬骨鱼类碳酸酐酶基因的适应性进化和遗传机制研究

碳酸盐碱性是淡水鱼类在盐碱水域的主要环境胁迫因子，对水产养殖业发展具有重要影响。在前期研究中，我们发现碳酸酐酶编码基因在瓦氏雅罗鱼适应极端碳酸盐碱性环境的适应性进化中受到了强烈选择。碳酸酐酶是生物体内CO2水合反应的关键催化酶，对水生生物维持酸碱平衡具有重要作用。为了深入解析碳酸酐酶基因在硬骨鱼类适应碳酸盐高碱环境的遗传基础，本项目拟以达里诺尔湖生存的瓦氏雅罗鱼为材料，通过分子系统学分析、扩增子测序、遗传变异位点挖掘和等位基因频率比较分析等手段，筛选定位与碳酸盐碱性环境适应性相关的碳酸酐酶基因、遗传变异位点和效应等位基因，并解析其功能调节机制；同时，在相似碱性生境的青海湖裸鲤等鱼类中针对碳酸酐酶基因开展等位基因频率分析，验证可能的趋同进化位点和分子调节机制。这些研究不仅有助于我们深入地解析硬骨鱼类适应极端碱性环境的适应性进化分子机制，同时还将为适应盐碱水域养殖的鱼类新品种选育提供重要参考。

Carbonic alkalinity is the key environmental stress factor to freshwater fish inhabiting saline-alkaline water and impacts aquaculture development substantially. Previously, we recognized significant selective pressure and selective sweeps in the genome regions encoding carbonic anhydrase in Leuciscus waleckii inhabiting extreme carbonate alkalinity. Carbonic anhydrases are key enzymes that catalyze the rapid interconversion of carbon dioxide and water to bicarbonate and protons, which play crucial role for acid-base regulation in aquatic organisms. To further explore the genetic diversity and adaptive mechanism underlying the alkaline adaptation in teleost, we propose genetic and evolutionary studies on carbonic anhydrase gene family in Leuciscus waleckii, including phylogenetic analysis, amplicon re-sequencing, genetic variation identification, allele frequency analysis, etc. The carbonic anhydrase genes and the causative alleles will be screened and identified underlying the carbonate alkalinity adaptation, and allelic specific gene function and genetic mechanism will by studied. The result will be also validated independently in some other teleost species inhabiting similar carbonate alkaline environment for investigating potential convergence evolution on carbonic anhydrase genes. The results will provide comprehensive understanding on adaptive evolution of teleost under carbonic alkaline pressure, and provide valuable genetic resource for selective breeding of alkaline resistant fish.