, Atlanta, GA, USA.
Department of Anatomy and Neurobiology, Program in Biomedical Forensic Sciences, Boston University School of Medicine, Boston, MA, USA.
Int J Legal Med. 2022 Sep;136(5):1201-1210. doi: 10.1007/s00414-022-02815-z. Epub 2022 Mar 30.
The present research assessed how the physical and chemical changes associated with decomposition affect the detection and identification of blood and semen evidence, as well as subsequent DNA analysis. A feeder pig (postmortem interval (PMI) < 3 h) was placed within the Boston University Outdoor Research Facility for a period of 22 days. Human blood and semen were individually dispensed onto multiple areas of two cotton t-shirts; one layer of fabric was placed above and below the pig and a control. One of each sample type was collected per day for a period of 22 days from each location. It was observed that both sample types when collected from beneath the pig exhibited the greatest decline in enzymatic activity over the course of testing, followed by samples from beneath the control, which can be inferred from the increase in negative screening results compared to the other samples. Spermatozoa were observed in nearly all semen samples, even when all screening results were negative, which lead to the generation of comparable DNA profiles for nearly all semen samples typed. Genetic typing of the blood samples beneath the pig and control rarely yielded comparable data while the samples from above yielded full profiles for all but a few samples tested.
本研究评估了与分解相关的物理和化学变化如何影响血液和精液证据的检测和识别，以及随后的 DNA 分析。将一头育肥猪（死后间隔时间 (PMI) < 3 小时）放置在波士顿大学户外研究设施内，为期 22 天。将人类血液和精液分别分配到两件棉质 t 恤的多个区域；将一层织物放在猪和对照物的上面和下面。每天从每个位置采集每种样本类型的一个样本，持续 22 天。观察到，当从猪下面采集这两种样本类型时，在整个测试过程中酶活性下降最大，其次是从对照物下面采集的样本，这可以从与其他样本相比，阴性筛查结果的增加推断出来。即使所有的筛查结果都是阴性，也几乎在所有的精液样本中都观察到了精子，这导致了几乎所有进行基因分型的精液样本都生成了可比的 DNA 图谱。来自猪和对照物下面的血液样本的基因分型很少产生可比的数据，而来自上面的样本除了少数几个测试样本外，都生成了完整的图谱。
