Replacing the first-generation dentition in pufferfish with a unique beak
Replacing the first-generation dentition in pufferfish with a unique beak
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DOI：
10.1073/pnas.1119635109
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发表时间：
2012-05-22
影响因子：
11.1
通讯作者：
Smith, Moya M.
中科院分区：
文献类型：
--
作者：
Fraser, Gareth J.;Britz, Ralf;Smith, Moya M.
硬骨鱼约占所有现存脊椎动物的一半。硬骨鱼类多样性的极端范围是显著的，特别是它们的颌骨和齿系的广泛的形态变异。一些最不寻常的齿系是在高度进化的硬骨鱼目中发现的，其中包括河豚，箱鲀，海洋太阳鱼和河豚。成年河豚（Tetraodontidae）显示出一个独特的鹦鹉般的喙颚，形成一个切割边缘，不同于任何其他硬骨鱼类。在这里，我们表明，尽管新奇的结构和发展，这种“喙”，它是由形成单独的第一代牙齿线的胚胎河豚下巴，与时间的发展和基因表达模式保守的最后共同祖先的硬骨鱼。大多数第一代幼虫的牙齿在发育过程中丢失。连续的牙齿更换过程中，只有四个副骺齿，顺序堆叠，多代，下颌长度的牙本质带，功能喙的发展之前。这些数据表明，牙齿的新奇，如河豚的喙，可以通过修改后的连续牙齿添加和更换在个体发育后期发展。我们的结论是，即使是高度衍生的形态结构，如河豚喙形式通过一个保守的发展baulan能够修改个体发育过程中微妙的重新指定的发展模块。
Teleost fishes comprise approximately half of all living vertebrates. The extreme range of diversity in teleosts is remarkable, especially, extensive morphological variation in their jaws and dentition. Some of the most unusual dentitions are found among members of the highly derived teleost order Tetraodontiformes, which includes triggerfishes, boxfishes, ocean sunfishes, and pufferfishes. Adult pufferfishes (Tetraodontidae) exhibit a distinctive parrot-like beaked jaw, forming a cutting edge, unlike in any other group of teleosts. Here we show that despite novelty in the structure and development of this "beak," it is initiated by formation of separate first-generation teeth that line the embryonic pufferfish jaw, with timing of development and gene expression patterns conserved from the last common ancestor of osteichthyans. Most of these first-generation larval teeth are lost in development. Continuous tooth replacement proceeds in only four parasymphyseal teeth, as sequentially stacked, multigenerational, jaw-length dentine bands, before development of the functional beak. These data suggest that dental novelties, such as the pufferfish beak, can develop later in ontogeny through modified continuous tooth addition and replacement. We conclude that even highly derived morphological structures like the pufferfish beak form via a conserved developmental bauplan capable of modification during ontogeny by subtle respecification of the developmental module.