Harvey Virginia L, Egerton Victoria M, Chamberlain Andrew T, Manning Phillip L, Buckley Michael
School of Earth, Atmospheric and Environmental Sciences, The University of Manchester, Manchester, M13 9PL, United Kingdom.
Department of Geology and Environmental Geosciences, College of Charleston, 66 George Street, Charleston, South Carolina, 29424, United States of America.
PLoS One. 2016 Mar 3;11(3):e0150650. doi: 10.1371/journal.pone.0150650. eCollection 2016.
Collagen is the dominant organic component of bone and is intimately locked within the hydroxyapatite structure of this ubiquitous biomaterial that dominates archaeological and palaeontological assemblages. Radiocarbon analysis of extracted collagen is one of the most common approaches to dating bone from late Pleistocene or Holocene deposits, but dating is relatively expensive compared to other biochemical techniques. Numerous analytical methods have previously been investigated for the purpose of screening out samples that are unlikely to yield reliable dates including histological analysis, UV-stimulated fluorescence and, most commonly, the measurement of percentage nitrogen (%N) and ratio of carbon to nitrogen (C:N). Here we propose the use of collagen fingerprinting (also known as Zooarchaeology by Mass Spectrometry, or ZooMS, when applied to species identification) as an alternative screening method for radiocarbon dating, due to its ability to provide information on collagen presence and quality, alongside species identification. The method was tested on a series of sub-fossil bone specimens from cave systems on Cayman Brac (Cayman Islands), chosen due to the observable range in diagenetic alteration, and in particular, the extent of mineralisation. Six (14)C dates, of 18 initial attempts, were obtained from remains of extinct hutia, Capromys sp. (Rodentia; Capromyidae), recovered from five distinct caves on Cayman Brac, and ranging from 393 ± 25 to 1588 ± 26 radiocarbon years before present (yr BP). All of the bone samples that yielded radiocarbon dates generated excellent collagen fingerprints, and conversely those that gave poor fingerprints also failed dating. Additionally, two successfully fingerprinted bone samples were screened out from a set of 81. Both subsequently generated (14)C dates, demonstrating successful utilisation of ZooMS as an alternative screening mechanism to identify bone samples that are suitable for 1(4)C analysis.
胶原蛋白是骨骼的主要有机成分，紧密地锁定在这种普遍存在的生物材料的羟基磷灰石结构中，这种生物材料在考古和古生物学组合中占主导地位。对提取的胶原蛋白进行放射性碳分析是测定晚更新世或全新世沉积物中骨骼年代最常用的方法之一，但与其他生化技术相比，年代测定相对昂贵。此前已经研究了许多分析方法，目的是筛选出不太可能得出可靠年代的样本，包括组织学分析、紫外线激发荧光，最常见的是测量氮含量百分比（%N）和碳氮比（C:N）。在此，我们建议使用胶原蛋白指纹识别技术（应用于物种识别时也称为质谱动物考古学，即ZooMS）作为放射性碳测年的替代筛选方法，因为它能够提供有关胶原蛋白的存在和质量的信息，同时还能进行物种识别。该方法在开曼布拉克岛（开曼群岛）洞穴系统的一系列亚化石骨骼标本上进行了测试，选择这些标本是因为其成岩变化的可观察范围，特别是矿化程度。在18次初步尝试中，从灭绝的胡蒂亚（Capromys sp.，啮齿目；科洛鼠科）的遗骸中获得了6个碳-14年代，这些遗骸是从开曼布拉克岛的5个不同洞穴中回收的，距今放射性碳年代范围为393±25至1588±26年（距今，yr BP）。所有产生碳-14年代的骨骼样本都产生了出色的胶原蛋白指纹，相反，那些指纹不佳的样本也未能测年成功。此外，从81个样本中筛选出了2个成功进行指纹识别的骨骼样本。随后这两个样本都产生了碳-14年代，证明成功利用ZooMS作为一种替代筛选机制来识别适合进行碳-14分析的骨骼样本。
