Abstract:
Midfacial morphology varies between hominoids, in particular between great apes and humans for which the face is small and retracted. The underlying developmental processes for these morphological differences are still largely unknown. Here, we investigate the cellular mechanism of maxillary development (bone modelling, BM), and how potential changes in this process may have shaped facial evolution. We analysed cross-sectional developmental series of gibbons, orangutans, gorillas, chimpanzees and present-day humans (n = 183). Individuals were organized into five age groups according to their dental development. To visualize each species\'s BM pattern and corresponding morphology during ontogeny, maps based on microscopic data were mapped onto species-specific age group average shapes obtained using geometric morphometrics. The amount of bone resorption was quantified and compared between species. Great apes share a highly similar BM pattern, whereas gibbons have a distinctive resorption pattern. This suggests a change in cellular activity on the hominid branch. Humans possess most of the great ape pattern, but bone resorption is high in the canine area from birth on, suggesting a key role of canine reduction in facial evolution. We also observed that humans have high levels of bone resorption during childhood, a feature not shared with other apes.
摘要:
面部中部形态在人形之间变化,特别是在大猿和人类之间,因为它们的脸很小并且缩回。这些形态差异的潜在发育过程在很大程度上仍然未知。这里,我们研究上颌发育的细胞机制(骨建模,BM),以及这个过程中的潜在变化如何影响面部进化。我们分析了长臂猿的横截面发育系列,猩猩,大猩猩,黑猩猩和现今人类(n=183)。根据牙齿发育情况,将个人分为五个年龄组。为了可视化每个物种在个体发育过程中的BM模式和相应的形态,基于微观数据的地图被绘制到使用几何形态计量学获得的特定物种年龄组的平均形状上。定量骨吸收的量并在物种之间进行比较。大猿有一个非常相似的BM模式,而长臂猿有独特的吸收模式。这表明原始分支上细胞活性的变化。人类拥有大部分的大猿模式,但是从出生开始,犬科地区的骨吸收很高,提示犬减少在面部进化中的关键作用。我们还观察到人类在童年时期有高水平的骨吸收,不与其他类人猿共享的功能。