Unique pattern of dietary adaptation in the dentition of Carnivora: its advantage and developmental origin
Unique pattern of dietary adaptation in the dentition of Carnivora: its advantage and developmental origin
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食肉目动物牙列独特的饮食适应模式：其优势和发育起源
DOI：
10.1098/rspb.2016.0375
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发表时间：
2016-06-15
期刊：
影响因子：
--
通讯作者：
Bessho K
中科院分区：
文献类型：
--
作者：
Asahara M;Saito K;Kishida T;Takahashi K;Bessho K
食肉动物在饮食多样性方面是一个成功的分类群。我们研究了食肉动物牙齿的饮食适应性及其牙齿多样性的发展背景，这可能有助于世系的成功。一个发育模型被测试和扩展来解释独特的变异性和在食肉动物牙齿中观察到的异常表型。食肉哺乳动物在磨牙上表现出两种截然不同的饮食适应模式，只有食肉动物进化出了新的变异性，显示出相对磨牙大小和第一磨牙形状之间的高度相关性。对Bmp7异源缺陷小鼠的研究表明，Bmp7对这两种牙齿性状具有多效性作用，而Bmp7表达可能较低。它的作用与在食肉动物中观察到的饮食适应模式一致，但在其他食肉哺乳动物中却没有观察到。分子进化分析表明，Bmp7序列在熊类进化过程中是通过自然选择进化而来的，这表明它在食肉动物牙列的变异中起着进化作用。通过小鼠实验和分子进化分析，我们推断了迄今为止谜样的熊齿（M2大于M1和M3）的因果机制。我们的研究结果证明了食肉动物如何获得新的牙齿变异，这有利于它们的饮食差异。
Carnivora is a successful taxon in terms of dietary diversity. We investigated the dietary adaptations of carnivoran dentition and the developmental background of their dental diversity, which may have contributed to the success of the lineage. A developmental model was tested and extended to explain the unique variability and exceptional phenotypes observed in carnivoran dentition. Carnivorous mammalian orders exhibited two distinct patterns of dietary adaptation in molars and only Carnivora evolved novel variability, exhibiting a high correlation between relative molar size and the shape of the first molar. Studies of Bmp7-hetero-deficient mice, which may exhibit lower Bmp7 expression, suggested that Bmp7 has pleiotropic effects on these two dental traits. Its effects are consistent with the pattern of dietary adaptation observed in Carnivora, but not that observed in other carnivorous mammals. A molecular evolutionary analysis revealed that Bmp7 sequence evolved by natural selection during ursid evolution, suggesting that it plays an evolutionary role in the variation of carnivoran dentition. Using mouse experiments and a molecular evolutionary analysis, we extrapolated the causal mechanism of the hitherto enigmatic ursid dentition (larger M2 than M1 and M3). Our results demonstrate how carnivorans acquired novel dental variability that benefits their dietary divergence.