Fagernäs Zandra, Salazar-García Domingo C, Haber Uriarte María, Avilés Fernández Azucena, Henry Amanda G, Lomba Maurandi Joaquín, Ozga Andrew T, Velsko Irina M, Warinner Christina
Department of Archaeogenetics, Max Planck Institute for the Science of Human History, 07745 Jena, Germany.
Department of Archaeogenetics, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103 Leipzig, Germany.
FEMS Microbes. 2022 Mar 3;3:xtac006. doi: 10.1093/femsmc/xtac006. eCollection 2022.
The oral cavity is a heterogeneous environment, varying in factors such as pH, oxygen levels, and salivary flow. These factors affect the microbial community composition and distribution of species in dental plaque, but it is not known how well these patterns are reflected in archaeological dental calculus. In most archaeological studies, a single sample of dental calculus is studied per individual and is assumed to represent the entire oral cavity. However, it is not known if this sampling strategy introduces biases into studies of the ancient oral microbiome. Here, we present the results of a shotgun metagenomic study of a dense sampling of dental calculus from four Chalcolithic individuals from the southeast Iberian peninsula (ca. 4500-5000 BP). Interindividual differences in microbial composition are found to be much larger than intraindividual differences, indicating that a single sample can indeed represent an individual in most cases. However, there are minor spatial patterns in species distribution within the oral cavity that should be taken into account when designing a study or interpreting results. Finally, we show that plant DNA identified in the samples is likely of postmortem origin, demonstrating the importance of including environmental controls or additional lines of biomolecular evidence in dietary interpretations.
口腔是一个异质环境，在pH值、氧气水平和唾液流量等因素方面存在差异。这些因素会影响牙菌斑中微生物群落的组成和物种分布，但目前尚不清楚这些模式在考古牙垢中能得到多好的体现。在大多数考古研究中，每个个体只研究一个牙垢样本，并假定它能代表整个口腔。然而，尚不清楚这种采样策略是否会给古代口腔微生物组的研究带来偏差。在此，我们展示了一项对来自伊比利亚半岛东南部四个铜石并用时代个体（约公元前4500 - 5000年）的牙垢进行密集采样的鸟枪法宏基因组研究结果。研究发现，个体间微生物组成的差异远大于个体内差异，这表明在大多数情况下，单个样本确实可以代表一个个体。然而，口腔内物种分布存在微小的空间模式，在设计研究或解释结果时应予以考虑。最后，我们表明在样本中鉴定出的植物DNA可能来自死后，这证明了在饮食解释中纳入环境对照或其他生物分子证据的重要性。
