Developmental genetic basis for the evolution of pelvic fin loss in the pufferfish Takifugu rubripes.
Developmental genetic basis for the evolution of pelvic fin loss in the pufferfish Takifugu rubripes.
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DOI：
10.1016/j.ydbio.2005.02.016
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发表时间：
2005-05
影响因子：
2.7
通讯作者：
Mikiko Tanaka;Laura A. Hale;A. Amores;Yi-Lin Yan;W. Cresko;Tohru Suzuki;J. Postlethwait
中科院分区：
文献类型：
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作者：
Mikiko Tanaka;Laura A. Hale;A. Amores;Yi-Lin Yan;W. Cresko;Tohru Suzuki;J. Postlethwait
成对的附肢是脊椎动物的一项关键的发育创新，它们最终进化成了四肢。古老的成对鳍和四肢的发育控制系统在颌骨脊椎动物中广泛保存。一些谱系，包括鲸鱼、一些火蜥蜴、蛇和许多鳍鱼，随着进化时间的推移，独立地失去了胸部、骨盆或两者的附属物。当不同的类群独立地进化出相似的发育形态时，它们是否使用相同的分子遗传机制？为了确定河豚骨盆缺失进化的发育遗传学基础，我们分离了四足动物中被认为对肢体发育至关重要的基因的河豚同源基因，包括肢体定位(Hoxc6，Hoxd9)、肢体芽起始(Pitx1，Tbx4，Tbx5)和肢体芽伸出(Shh，Fgf10)，并研究了它们在河豚发育过程中的表达模式。结果表明，河豚不能发生芽的伸展和起始，骨盆的缺失与Hoxd9a的表达变化有关，Hoxd9a是三刺刺鱼腹鳍位置的标志。这些结果排除了附件、外延生长和起始基因的改变是河豚腹鳍缺失的最早发育缺陷的可能性，并提示Hoxd9a在河豚外侧中胚层的表达变化可能是河豚骨盆缺失的原因。这一机制似乎与刺鱼骨盆丢失的机制不同，表明不同的类群可以通过不同的机制进化出相似的表型。
Paired appendages were a key developmental innovation among vertebrates and they eventually evolved into limbs. Ancient developmental control systems for paired fins and limbs are broadly conserved among gnathostome vertebrates. Some lineages including whales, some salamanders, snakes, and many ray-fin fish, independently lost the pectoral, pelvic, or both appendages over evolutionary time. When different taxa independently evolve similar developmental morphologies, do they use the same molecular genetic mechanisms? To determine the developmental genetic basis for the evolution of pelvis loss in the pufferfish Takifugu rubripes (fugu), we isolated fugu orthologs of genes thought to be essential for limb development in tetrapods, including limb positioning (Hoxc6, Hoxd9), limb bud initiation (Pitx1, Tbx4, Tbx5), and limb bud outgrowth (Shh, Fgf10), and studied their expression patterns during fugu development. Results showed that bud outgrowth and initiation fail to occur in fugu, and that pelvis loss is associated with altered expression of Hoxd9a, which we show to be a marker for pelvic fin position in three-spine stickleback Gasterosteus aculeatus. These results rule out changes in appendage outgrowth and initiation genes as the earliest developmental defect in pufferfish pelvic fin loss and suggest that altered Hoxd9a expression in the lateral mesoderm may account for pelvis loss in fugu. This mechanism appears to be different from the mechanism for pelvic loss in stickleback, showing that different taxa can evolve similar phenotypes by different mechanisms.