PDF(Pubmed)
Abstract：
Understanding how epigenetic factors impact dental phenotypes can help refine the use of teeth for elucidating biological relationships among human populations. We explored relationships among crown size, principal cusp spacing, and accessory cusp expression in maxillary dental casts of nutritionally supplemented (n = 34) and non-supplemented (n = 39) individuals from Tezonteopan, Mexico. We hypothesized that the non-supplemented group would exhibit smaller molar crowns and reduced intercusp spacing. Since intercusp spacing is thought to be more sensitive to epigenetic influences than crown size, we predicted that the supplemented and non-supplemented groups would differ more in the former than the latter. Previous work suggests that molar accessory cusp expression may be elevated under conditions of stress. We therefore expected evidence of greater Carabelli and Cusp 5 trait expression in the non-supplemented group. We further hypothesized that anterior teeth would be affected by nutritional stress during development, with the non-supplemented group having smaller anterior tooth crowns and therefore limited space to form the tuberculum dentale. Finally, we tested whether the presence of molar accessory traits followed predictions of the Patterning Cascade Model of tooth morphogenesis in the entire sample. Our results supported the expectation that cusp spacing would differ more than molar crown size between the two groups. Carabelli trait showed little evidence of frequency differences between groups, but some evidence of greater trait scores in the non-supplemented group. The non-supplemented group also showed evidence of greater Cusp 5 frequency and expression. In the central incisors and canines, there was strong evidence for smaller crown sizes and reduced tuberculum dentale frequency in the non-supplemented group. With both groups pooled together, there was strong evidence of closer mesiodistal distances among principal cusps in molars with accessory cusps, a finding that is consistent with the PCM. Overall, our findings suggest that nutritional stress may affect accessory cusp expression.
摘要：
了解表观遗传因素如何影响牙齿表型可以帮助改善牙齿的使用，以阐明人类群体之间的生物学关系。我们探索了皇冠大小之间的关系，主尖点间距,和来自Tezonteopan的营养补充（n=34）和未补充（n=39）个体的上颌牙模中的副尖点表达，墨西哥。我们假设未补充的组将表现出较小的磨牙冠和较小的齿间间距。由于插入间距被认为比牙冠大小对表观遗传影响更敏感，我们预测补充组和非补充组的差异在前者中将大于后者。先前的工作表明，在应激条件下，磨牙副尖牙的表达可能会升高。因此，我们预计在未补充组中有更大的Carabelli和Cusp5性状表达的证据。我们进一步假设前牙在发育过程中会受到营养压力的影响，未补充组的前牙冠较小，因此形成牙结节的空间有限。最后,我们测试了磨牙辅助特征的存在是否遵循整个样本中牙齿形态发生的PatternCascade模型的预测。我们的结果支持以下预期：两组之间的尖点间距将比磨牙冠大小差异更大。Carabelli特征显示组间频率差异的证据很少，但一些证据表明，非补充组的性状得分更高。未补充组也显示出更大的Cusp5频率和表达的证据。在中央门牙和犬齿中，有强有力的证据表明，在未补充的组中，牙冠尺寸较小，结节发生频率降低。两组都集中在一起，有强有力的证据表明，磨牙的主要尖端之间的近远端距离与辅助尖端，这一发现与PCM一致。总的来说,我们的发现提示营养应激可能影响副尖点的表达.
