A new model for ancient DNA decay based on paleogenomic meta-analysis.
A new model for ancient DNA decay based on paleogenomic meta-analysis.
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DOI：
10.1093/nar/gkx361
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发表时间：
2017-06-20
影响因子：
14.9
通讯作者：
Allaby RG
中科院分区：
文献类型：
--
作者：
Kistler L;Ware R;Smith O;Collins M;Allaby RG
DNA在不同环境中的考古学和古生物学时间尺度上的持续存在导致了古基因组学研究的革命性机构，但DNA降解的动力学仍然知之甚少。我们分析了185个古基因组数据集，并将DNA存活率与环境变量和样本年龄进行了比较。我们发现胞嘧啶脱氨遵循传统的热年龄模型，但我们发现DNA片段化和样品年龄之间没有相关性，即使在控制环境变量的时间跨度分析。我们提出了一个古老的DNA衰变模型，其中碎片迅速达到一个阈值，随后放缓。在许多情况下，观察到的DNA随时间的损失可能是由于大量扩散过程，突出了组织和环境创建有效的封闭系统用于DNA保存的重要性。由于已发表的基因组数据集的可用性，这种DNA降解模型主要基于哺乳动物骨骼样本。对模型的不断完善，以反映不同的生物系统和组织类型，将进一步提高我们对古代DNA分解动力学的理解。
The persistence of DNA over archaeological and paleontological timescales in diverse environments has led to a revolutionary body of paleogenomic research, yet the dynamics of DNA degradation are still poorly understood. We analyzed 185 paleogenomic datasets and compared DNA survival with environmental variables and sample ages. We find cytosine deamination follows a conventional thermal age model, but we find no correlation between DNA fragmentation and sample age over the timespans analyzed, even when controlling for environmental variables. We propose a model for ancient DNA decay wherein fragmentation rapidly reaches a threshold, then subsequently slows. The observed loss of DNA over time may be due to a bulk diffusion process in many cases, highlighting the importance of tissues and environments creating effectively closed systems for DNA preservation. This model of DNA degradation is largely based on mammal bone samples due to published genomic dataset availability. Continued refinement to the model to reflect diverse biological systems and tissue types will further improve our understanding of ancient DNA breakdown dynamics.