RAD-seq技术在植物物证个体认定中的应用

在犯罪案件现场发现与嫌疑人(或受害人)相关联的植物物证,鉴定它们来源和进行个体识别,可为案件的调查取证提供有价值的证据或线索.该研究采用一种RAD-seq技术对18个桂花样品(15个已知样本、3个盲测样本)进行DNA建库和高通量测序,序列多态性分析,评估其遗传多样性,并用基于SNP和基于k-mer频谱的2种比较分析方法探讨了RAD-seq数据用于个体识别的科学性和对植物物证进行同一性认定的可行性.结果表明,2种方法都能成功识别3个盲测样本.相比较而言,基于k-mer频谱的方法在稳定性和自动化程度上要优于基于SNP亲缘关系树的分析方法,更易推广到公安物证鉴别应用中.RAD-seq技术结合该文的分析方法能够识别出未知植物物证样品A,B和C分别对应于植物物证桂花1,4和11,实现了对案件中关联植物物证进行精确检验鉴定的方法和一个小型鉴定实例,但其识别能力有待扩展到更大样本集和更多物种中.

Application of RAD-seq Technology in Individual Identification of Plant Material Evidence

Plant evidence related to the suspect/victim found at the crime scene can provide valuable evidence or clues for investigation and evidence collection of the case. In a study reported in this paper, an RAD-seq (restriction-site associated DNA sequencing) technique was used to build a database and make high-throughput sequencing for 18 samples of Osmanthus (15 known samples and 3 blind samples), analyze their sequence polymorphism and evaluate their genetic diversity. Two kinds of comparative analysis method, one based on SNP (single nucleotide polymorphism) and the other on k-mer spectrum, were employed to discuss the scientific nature of RAD-seq data for individual identification and the feasibility of identity identification of plant material evidence. The results showed that both methods could successfully identify the three blind samples. Comparatively, the k-mer spectrum-based method was superior to the analysis method based on the SNP genetic relationship tree in stability and automation degree. It was easier to apply to the public security material evidence of identification. In conclusion, the RAD-seq technology used in combination with the analysis method successfully identified the three unknown plant material evidence samples A, B and C, and they corresponded to the sweet scented osmanthus 1, 4 and 11, respectively. It has provided a method for accurate examination and identification of related plant material evidence in a case and a small identification example, but its ability of identification is to be extended to a larger set of samples and more plant species.