Bouwman Abigail S, Chilvers Elizabeth R, Brown Keri A, Brown Terence A
Faculty of Life Sciences, University of Manchester, Manchester M60 1QD, United Kingdom.
Am J Phys Anthropol. 2006 Nov;131(3):428-31. doi: 10.1002/ajpa.20411.
We present a method to distinguish authentic ancient DNA from contaminating DNA in a human bone. This is achieved by taking account of the spatial distribution of the various sequence families within the bone and the extent of degradation of the template DNAs, as revealed by the error content of the sequences. To demonstrate the veracity of the method, we handled two ancient human tibiae in order to contaminate them with modern DNA, and then subjected segments of the bones to various decontaminating treatments, including removal of the outer 1-2 mm, before extracting DNA, cloning, and obtaining a total of 107 mitochondrial DNA sequences. Sequences resulting from the deliberate contamination were located exclusively in the outer 1-2 mm of the bones, and only one of these 27 sequences contained an error that could be ascribed to DNA degradation. A second, much smaller set of relatively error-free sequences, which we ascribe to contamination during excavation or curation, was also located exclusively in the outer 1-2 mm. In contrast, a family of 72 sequences, displaying extensive degradation products but identifiable as haplogroup U5a1a, was distributed throughout one of the bones and represents the authentic ancient DNA content of this specimen.
我们提出了一种方法，用于区分人类骨骼中真实的古代DNA和污染DNA。这是通过考虑骨骼内各种序列家族的空间分布以及模板DNA的降解程度来实现的，序列的错误含量揭示了这种降解程度。为了证明该方法的准确性，我们处理了两根古代人类胫骨，用现代DNA对其进行污染，然后在提取DNA、克隆并获得总共107个线粒体DNA序列之前，对骨骼片段进行各种去污处理，包括去除外层1-2毫米。故意污染产生的序列仅位于骨骼外层1-2毫米处，这27个序列中只有一个包含可归因于DNA降解的错误。另一组数量少得多、相对无错误的序列，我们将其归因于挖掘或保管过程中的污染，也仅位于外层1-2毫米处。相比之下，一组72个序列，显示出广泛的降解产物但可鉴定为单倍群U5a1a，分布在其中一根骨骼的整个区域，代表了该样本的真实古代DNA含量。
