Interdisciplinary Graduate School of Agriculture and Engineering, University of Miyazaki, Miyazaki 889-2192, Japan; Miyazaki Prefectural Police Forensic Science Laboratory, Miyazaki Prefectural Police H.Q., Miyazaki 880-8509, Japan.
Miyazaki Prefectural Police Forensic Science Laboratory, Miyazaki Prefectural Police H.Q., Miyazaki 880-8509, Japan.
Forensic Sci Int. 2022 Jun;335:111284. doi: 10.1016/j.forsciint.2022.111284. Epub 2022 Mar 26.
In forensic investigations, it is crucial to detect a suspect's DNA from the available evidence. In an outdoor crime scene, the evidence may be mixed with the soil. However, soil is speculated to inhibit DNA extraction from forensic science samples. In the field of soil microbiology, it is necessary to extract DNA directly from soil to analyse its microbial composition. In this study, we investigated whether skim milk used in procedure of DNA extraction from soil samples could be applied to forensic science to enhance human DNA extraction efficiency from soil mixed with forensic evidence, such as blood, buccal cells, and skin cells. The use of additive reagents, skim milk and bovine serum albumin (BSA), are known to blocking reagent. In the selection of additive reagents experiment, about blood sample, using the skim milk and BSA were found to increase the DNA yield. Therefore, we observed extracted DNA yield from blood, buccal cells, and skin cells when skim milk and BSA were used as additive reagents. The DNA recovery rate was high across all samples upon addition of skim milk. However, in STR analysis, a non-specific peak was detected in the extracted DNA in the presence of skim milk, which was not detected in the presence of BSA, indicating its suitability in forensic analysis. Our study suggests that addition of BSA can efficiently aid the extraction of DNA from forensic evidence mixed with soil.
在法医学调查中，从可用证据中检测嫌疑人的 DNA 至关重要。在户外犯罪现场，证据可能与土壤混合。然而，土壤被推测会抑制法医样本的 DNA 提取。在土壤微生物学领域，有必要直接从土壤中提取 DNA 来分析其微生物组成。在这项研究中，我们研究了在从土壤样本中提取 DNA 的过程中使用的脱脂乳是否可以应用于法医学，以提高从混合有法医证据（如血液、口腔细胞和皮肤细胞）的土壤中提取人类 DNA 的效率。已知添加试剂，如脱脂乳和牛血清白蛋白（BSA），可以作为阻断试剂。在添加剂试剂的选择实验中，发现使用脱脂乳和 BSA 可以增加血液样本的 DNA 产量。因此，我们观察了从血液、口腔细胞和皮肤细胞中提取 DNA 时使用脱脂乳和 BSA 作为添加剂试剂的情况。添加脱脂乳后，所有样本的 DNA 回收率均较高。然而，在 STR 分析中，在存在脱脂乳的情况下检测到提取 DNA 中存在非特异性峰，而在存在 BSA 的情况下则未检测到，表明其适合法医学分析。我们的研究表明，添加 BSA 可以有效地辅助从混合有土壤的法医证据中提取 DNA。
