Most extant vertebrates display a high variety of tooth and tooth-like organs (odontodes) that vary in shape, position over the body and nature of composing tissues. The development of these structures is known to involve similar genetic cascades and teeth and odontodes are believed to share a common evolutionary history. Gene expression patterns have previously been compared between mammalian and teleost tooth development but we highlight how the comparative framework was not always properly defined to deal with different tooth types or tooth developmental stages. Larger-scale comparative analyses also included cartilaginous fishes: sharks display oral teeth and dermal scales for which the gene expression during development started to be investigated in the small-spotted catshark Scyliorhinus canicula during the past decade. We report several descriptive approaches to analyse the embryonic tooth and caudal scale gene expressions in S. canicula. We compare these expressions wih the ones reported in mouse molars and teleost oral and pharyngeal teeth and highlight contributions and biases that arise from these interspecific comparisons. We finally discuss the evolutionary processes that can explain the observed intra and interspecific similarities and divergences in the genetic cascades involved in tooth and odontode development in jawed vertebrates. This article is protected by copyright. All rights reserved.

中文翻译：

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下颌脊椎动物牙齿和齿突的进化发育遗传学：从弹鳃研究的角度

大多数现存的脊椎动物显示出种类繁多的牙齿和齿状器官（齿状体），它们的形状、在身体上的位置和组成组织的性质各不相同。已知这些结构的发展涉及类似的遗传级联，并且牙齿和齿科动物被认为具有共同的进化历史。之前已经在哺乳动物和硬骨鱼牙齿发育之间比较了基因表达模式，但我们强调了比较框架并不总是正确定义以处理不同的牙齿类型或牙齿发育阶段。更大规模的比较分析还包括软骨鱼类：鲨鱼显示出口腔牙齿和真皮鳞片，在过去十年中，开始在小斑点猫鲨 Scyliorhinus canicula 中研究发育过程中的基因表达。我们报告了几种描述性方法来分析 S. canicula 中的胚胎牙齿和尾鳞基因表达。我们将这些表达与在小鼠臼齿和硬骨鱼口腔和咽部牙齿中报告的表达进行比较，并强调这些种间比较产生的贡献和偏见。我们最后讨论了进化过程，这些进化过程可以解释观察到的下颌脊椎动物牙齿和齿状体发育所涉及的遗传级联中的种内和种间相似性和差异。本文受版权保护。版权所有。我们将这些表达与在小鼠臼齿和硬骨鱼口腔和咽部牙齿中报告的表达进行比较，并强调这些种间比较产生的贡献和偏见。我们最后讨论了进化过程，这些进化过程可以解释观察到的下颌脊椎动物牙齿和齿状体发育所涉及的遗传级联中的种内和种间相似性和差异。本文受版权保护。版权所有。我们将这些表达与在小鼠臼齿和硬骨鱼口腔和咽部牙齿中报道的表达进行比较，并强调这些种间比较产生的贡献和偏见。我们最后讨论了进化过程，这些进化过程可以解释观察到的下颌脊椎动物牙齿和齿状动物发育所涉及的遗传级联中的种内和种间相似性和差异。本文受版权保护。版权所有。