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| 鲽形目鱼类Hoxd12a基因适应性进化及其在半滑舌鳎中的组织表达分析 |
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汪凯欣1, 张楠楠1, 吴文超1, 吕文拯1, 刘立芹2,1, 吕振明2,1, 龚 理2,1
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1.浙江海洋大学海洋科学与技术学院 浙江舟山;2.海洋生物种质资源发掘利用国家地方联合工程研究中心 浙江舟山
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| 摘要: |
| Hox基因家族在后生动物身体前后轴的形成过程中发挥至关重要的调控作用，其中Hoxd12a基因已被证实与鱼类胸鳍和四足动物四肢发育密切相关。鲽形目鱼类胸鳍普遍短小甚至缺失等现象是鱼形动物进化史上显著的形态创新，然而该形态创新背后的遗传机制仍不清楚。为揭示鲽形目胸鳍退化的可能分子基础，以Hoxd12a基因为突破口，探究鲽形目鱼类胸鳍不同程度退化是否与该基因变异有关；同时以半滑舌鳎为代表，揭示Hoxd12a基因的cDNA序列特征及其在包括鱼鳍在内的各个组织中的表达水平。结果显示Hoxd12a基因在鲽形目基因组中受到正选择，其中5个正选择位点或者引起氨基酸理化性质发生变化，或者导致蛋白质三级结构发生改变。扩增得到了Hoxd12a基因的cDNA全序列，其长度为2 563 bp，包含670 bp的5’非编码区，852 bp的开放阅读框序列以及1 041 bp的3’非编码区。组织表达分析显示Hoxd12a基因在各生长阶段不同组织中均有表达，但其在鱼鳍中表达水平明显高于肠、肝、脑等组织，提示该基因在鱼鳍发育以及维持鱼鳍功能发挥重要作用。研究结果不仅为挖掘鲽形目鱼类胸鳍退化的分子机制提供思路，同时也为深入理解基因与表型之间的关系奠定理论基础。 |
| 关键词: 鲆鲽类 Hox基因 正选择 表达模式 |
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| 基金项目:浙江省属高校基本科研业务费项目(2024J005-2) |
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| ADAPTIVE EVOLUTION OF HOXD12A GENE IN FLATFISH AND ITS TISSUE EXPRESSION ANALYSIS IN CYNOGLOSSUS SEMILAEVIS |
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WANG Kai-Xin1, ZHANG Nan-Nan1, WU Wen-Chao1, LYU Wen-Zheng1, LIU Li-Qin2, LYU Zhen-Ming2, GONG Li2
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1.Zhejiang Ocean University, Marine Science and Technology College;2.National and Provincial Joint Engineering Research Centre for Marine Germplasm Resources Exploration and Utilization
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| Abstract: |
| Hox genes play an important role in shaping the body axis of animals. Specifically, Hoxd12a gene was confirmed in the development of pectoral fin in fishes and limb in tetrapods. Flatfishes, generally exhibiting short, small, or even absent pectoral fins, which represents a significant innovation in the body evolution. However, the genetic machinisms behind this innovation have been largely unknown. To establish the potential molecular basis for pectoral fin reduction in flatfishes, Hoxd12a gene was focused as a starting point to investigate whether gene variation is linked to different degrees of pectoral fin reduction in flatfishes. Additionally, Cynoglossus semilaevis was selected as a representative to reveal the cDNA sequence characteristics and to examine its expression levels in various tissues, including the fins. The results indicated that Hoxd12a gene in flatfish genomes had undergone positive selection, with five positive selected sites either leading to changes in the physicochemical properties of amino acids or alteration in the tertiary structure of the protein. The full-length cDNA sequence of Hoxd12a gene was successfully amplified, spanning 2 563 bp, which includes a 670 bp 5' untranslated region, an 852 bp open reading frame, and a 1 041 bp 3' untranslated region. Expression analysis showed that Hoxd12a was expressed across various tissues at different growth stages, with significantly higher expression in fins than other tissues such as the intestine, liver, and brain, which suggested the significant role in fin development and the maintenance of fin function. These findings not only provide insights into the molecular mechanisms underlying pectoral fin reduction in flatfishes, but also establish a theoretical foundation for understanding the relationship between genes and phenotypes. |
| Key words: flatfish Hox genes positive selection expression pattern |