Department of Anthropology, New York University, New York, NY, USA.
New York Consortium in Evolutionary Primatology, New York, NY, USA.
J R Soc Interface. 2022 Feb;19(187):20210820. doi: 10.1098/rsif.2021.0820. Epub 2022 Feb 23.
The evolution of modern human reproductive scheduling is an aspect of our life history that remains vastly uncomprehended. The present work aims to address this gap by validating a non-destructive cutting-edge methodology to infer adult life-history events on modern teeth with known life history and then applying it to fossil specimens. We use phase-contrast synchrotron X-ray microtomography to visualize the dental cementum of 21 specimens: nine contemporary humans; 10 Neanderthals from Krapina (Croatia, 130-120 kyr); one Neolithic from Ajmana (Serbia); and one Mesolithic from Vlasac (Serbia). We were able to correctly detect and time (root mean square error = 2.1 years; = 0.98) all reproductive (menarche, parturition, menopause) and other physiologically impactful events in the modern sample. Nonetheless, we could not distinguish between the causes of the events detected. For the fossil specimens, we estimated age at death and age at occurrence of biologically significant events. Finally, we performed an exploratory analysis regarding possible sexual dimorphism in dental cementum microstructure, which allowed us to correctly infer the sex of the Neolithic specimen, for which the true value was known via DNA analysis.
现代人的生殖时间安排的进化是我们生活史中一个尚未被充分理解的方面。本研究旨在通过验证一种非破坏性的前沿方法来解决这一空白，该方法可以根据已知生活史推断现代牙齿上的成年生活史事件，然后将其应用于化石标本。我们使用相衬同步加速器 X 射线微断层扫描技术来可视化 21 个标本的牙骨质：9 个当代人类；10 个来自克拉皮纳（克罗地亚，130-120 千年前）的尼安德特人；1 个来自阿杰马纳（塞尔维亚）的新石器时代样本；1 个来自弗拉萨克（塞尔维亚）的中石器时代样本。我们能够正确地检测并确定（均方根误差 = 2.1 年； = 0.98）现代样本中所有的生殖（初潮、分娩、绝经）和其他对生理有影响的事件的时间。尽管如此，我们无法区分检测到的事件的原因。对于化石标本，我们估计了死亡年龄和发生具有生物学意义事件的年龄。最后，我们对牙骨质微观结构中可能存在的性别二态性进行了探索性分析，这使我们能够正确推断出具有已知 DNA 分析真实性别值的新石器时代标本的性别。
