Center for Human Identification, University of North Texas Health Science Centergrid.266871.c, Fort Worth, Texas, USA.
Department of Microbiology, Immunology, and Genetics, University of North Texas Health Science Centergrid.266871.c, Fort Worth, Texas, USA.
Appl Environ Microbiol. 2021 Sep 28;87(20):e0120821. doi: 10.1128/AEM.01208-21. Epub 2021 Aug 11.
Microbial DNA, shed from human skin, can be distinctive to its host and, thus, help individualize donors of forensic biological evidence. Previous studies have utilized single-locus microbial DNA markers (e.g., 16S rRNA) to assess the presence/absence of personal microbiota to profile human hosts. However, since the taxonomic composition of the microbiome is in constant fluctuation, this approach may not be sufficiently robust for human identification (HID). Multimarker approaches may be more powerful. Additionally, genetic differentiation, rather than taxonomic distinction, may be more individualizing. To this end, the nondominant hands of 51 individuals were sampled in triplicate ( = 153). They were analyzed for markers in the hidSkinPlex, a multiplex panel comprising candidate markers for skin microbiome profiling. Single-nucleotide polymorphisms (SNPs) with the highest Wright's fixation index (F) estimates were then selected for predicting donor identity using a support vector machine (SVM) learning model. F is an estimate of the genetic differences within and between populations. Three different SNP selection criteria were employed: SNPs with the highest-ranking F estimates (i) common between any two samples regardless of markers present (termed ); (ii) each marker common between samples (termed ); and (iii) common to all samples used to train the SVM algorithm for HID (termed ). The SNPs chosen based on criteria for , , and methods resulted in an accuracy of 92.00%, 94.77%, and 88.00%, respectively. The results support that estimates of F, combined with SVM, can notably improve forensic HID via skin microbiome profiling. There is a need for additional genetic information to help identify the source of biological evidence found at a crime scene. The human skin microbiome is a potentially abundant source of DNA that can enable the identification of a donor of biological evidence. With microbial profiling for human identification, there will be an additional source of DNA to identify individuals as well as to exclude individuals wrongly associated with biological evidence, thereby improving the utility of forensic DNA profiling to support criminal investigations.
微生物 DNA 从人体皮肤脱落，可以作为其宿主的独特特征，从而帮助鉴定法医生物证据的供体。先前的研究已经利用单一位点微生物 DNA 标记物（例如 16S rRNA）来评估个人微生物群的存在/缺失情况，以对人类宿主进行分析。然而，由于微生物组的分类组成不断变化，这种方法可能不足以进行人类识别（HID）。多标记方法可能更强大。此外，遗传分化而不是分类差异可能更具个体性。为此，对 51 名个体的非优势手进行了三次重复采样（ = 153）。对 hidSkinPlex 中的标记物进行了分析，hidSkinPlex 是一个包含皮肤微生物组分析候选标记物的多重面板。然后，使用支持向量机（SVM）学习模型，选择具有最高 Wright 固定指数（F）估计值的单核苷酸多态性（SNP）来预测供体身份。F 是种群内和种群间遗传差异的估计值。采用了三种不同的 SNP 选择标准：（i）无论存在何种标记物，任何两个样本之间排名最高的 F 估计值的 SNP（称为）；（ii）样本之间共有的每个标记物（称为）；以及（iii）用于训练 SVM 算法进行 HID 的所有样本共有的 SNP（称为）。基于标准选择的 SNP 结果分别为 92.00%、94.77%和 88.00%。结果支持 F 的估计值与 SVM 相结合，通过皮肤微生物组分析可以显著提高法医 HID 的准确性。 需要更多的遗传信息来帮助识别犯罪现场发现的生物证据的来源。人类皮肤微生物组是一种潜在丰富的 DNA 来源，可以实现生物证据供体的识别。通过微生物鉴定进行人类识别，将有另一个 DNA 来源来识别个体，并排除与生物证据错误相关的个体，从而提高法医 DNA 分析在支持犯罪调查方面的实用性。
