Cortical bone and dentine share similarities in their embryological origin, development, and genetic background. Few analyses have combined the study of cortical bone and dentine to quantify their covariation relative to endogenous and exogenous factors. However, knowing how these tissues relate in individuals is of great importance to decipher the factors acting on their evolution, and ultimately to understand the mechanisms responsible for the different patterns of tissue proportions shown in hominins. The aims of this study are to examine age-, sex-, and ancestry-related variation in cortical bone and dentine volumes, and to preliminary assess the possible covariation between these tissues in modern humans and in five composite Neandertals. The modern analytical sample includes 12 immature individuals from France and 49 adults from France and South Africa. Three-dimensional tissue proportions were assessed from microtomographic records of radii and permanent maxillary canines. Results suggest ontogenic differences and a strong sexual dimorphism in cortical bone and dentine developments. The developmental pattern of dentine also seems to vary according to individual's ancestry. We measure a stronger covariation signal between cortical bone and dentine volumes than with any other dental tissue. A more complex covariation pattern is shown when splitting the modern sample by age, sex, and ancestry, as no signal is found in some subsamples while others show a covariation between cortical bone and either crown or radicular dentine. Finally, no difference in cortical bone volume is noticed between the modern young adults and the five young adult composite Neandertals from Marine Isotopic Stages (MIS) 5 and 3. Greater dentine Cortical bone and dentine (co)variation volumes are measured in the MIS 5 chimeric Neandertals whereas a strong interpopulation variation in dentine thickness is noticed in the MIS 3 chimeric Neandertals. Further research on the cortical bonedentine covariation will increase understanding of the impact of endogenous and exogenous factors on the development of the mineralized tissues.

中文翻译：

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对现代人类皮质骨和牙本质体积的年龄、性别和祖先相关变异的评估，以及对晚期智人皮质骨-牙本质共变的初步评估。

皮质骨和牙本质在胚胎起源、发育和遗传背景方面具有相似之处。很少有分析结合皮质骨和牙本质的研究来量化它们相对于内源性和外源性因素的协变。然而，了解这些组织在个体中的关系对于破译影响其进化的因素并最终了解古人类不同组织比例模式的机制非常重要。本研究的目的是检查皮质骨和牙本质体积中与年龄、性别和血统相关的变化，并初步评估现代人类和五种复合尼安德特人中这些组织之间可能存在的协变。现代分析样本包括来自法国的 12 名未成年个体和来自法国和南非的 49 名成年个体。根据半径和上颌恒尖牙的显微断层扫描记录评估三维组织比例。结果表明，皮质骨和牙本质发育存在个体差异和强烈的性别二态性。牙本质的发育模式似乎也根据个人的血统而有所不同。我们测量到皮质骨和牙本质体积之间比任何其他牙科组织更强的协变信号。当按年龄、性别和血统分割现代样本时，会显示出更复杂的协变模式，因为在某些子样本中没有发现信号，而其他子样本则显示皮质骨与牙冠或根状牙本质之间的协变。最后，现代年轻人和来自海洋同位素阶段 (MIS) 5 和 3 的五种年轻复合尼安德特人之间的皮质骨体积没有发现差异。更大的牙本质皮质骨和牙本质（共）变异体积在 MIS 5 中测量嵌合尼安德特人，而 MIS 3 嵌合尼安德特人的牙本质厚度存在强烈的群体间差异。对皮质骨牙本质共变的进一步研究将增加对内源性和外源性因素对矿化组织发育影响的理解。