Ward J, Peakall R, Gilmore S R, Robertson J
School of Botany and Zoology, Australian National University, Canberra, ACT 0200, Australia.
Forensic Sci Int. 2005 Sep 10;152(2-3):121-31. doi: 10.1016/j.forsciint.2004.07.015.
Our present inability to rapidly, accurately and cost-effectively identify trace botanical evidence remains the major impediment to the routine application of forensic botany. Grasses are amongst the most likely plant species encountered as forensic trace evidence and have the potential to provide links between crime scenes and individuals or other vital crime scene information. We are designing a molecular DNA-based identification system for grasses consisting of several PCR assays that, like a traditional morphological taxonomic key, provide criteria that progressively identify an unknown grass sample to a given taxonomic rank. In a prior study of DNA sequences across 20 phylogenetically representative grass species, we identified a series of potentially informative indels in the grass mitochondrial genome. In this study we designed and tested five PCR assays spanning these indels and assessed the feasibility of these assays to aid identification of unknown grass samples. We confirmed that for our control set of 20 samples, on which the design of the PCR assays was based, the five primer combinations produced the expected results. Using these PCR assays in a 'blind test', we were able to identify 25 unknown grass samples with some restrictions. Species belonging to genera represented in our control set were all correctly identified to genus with one exception. Similarly, genera belonging to tribes in the control set were correctly identified to the tribal level. Finally, for those samples for which neither the tribal or genus specific PCR assays were designed, we could confidently exclude these samples from belonging to certain tribes and genera. The results confirmed the utility of the PCR assays and the feasibility of developing a robust full-scale usable grass identification system for forensic purposes.
目前，我们无法快速、准确且经济高效地识别微量植物证据，这仍然是法医植物学常规应用的主要障碍。草类是作为法医微量证据最有可能遇到的植物物种之一，有潜力提供犯罪现场与个人之间的联系或其他重要的犯罪现场信息。我们正在设计一种基于分子DNA的草类识别系统，该系统由几种聚合酶链式反应（PCR）分析方法组成，就像传统的形态分类学检索表一样，提供逐步将未知草类样本鉴定到给定分类等级的标准。在先前一项对20个具有系统发育代表性的草类物种的DNA序列研究中，我们在草类线粒体基因组中鉴定出一系列潜在的信息插入缺失。在本研究中，我们设计并测试了跨越这些插入缺失的五种PCR分析方法，并评估了这些分析方法辅助鉴定未知草类样本的可行性。我们证实，对于作为PCR分析方法设计基础的20个样本的对照集，这五种引物组合产生了预期结果。在“盲测”中使用这些PCR分析方法，我们能够在有一些限制的情况下鉴定出25个未知草类样本。我们对照集中所代表属的物种，除了一个例外，都被正确鉴定到属。同样，对照集中属于部落的属被正确鉴定到部落级别。最后，对于那些既未设计部落特异性也未设计属特异性PCR分析方法的样本，我们可以有把握地排除这些样本属于某些部落和属的可能性。结果证实了PCR分析方法的实用性以及开发一个强大的、可全面用于法医目的的草类识别系统的可行性。
