Biology Division, Victoria Police Forensic Services Centre, 31 Forensic Drive, MacLeod, Victoria 3085, Australia; Department of Genetics, School of Molecular Sciences, La Trobe University, Bundoora, Victoria 3086, Australia.
Forensic Sci Int. 2013 Dec 10;233(1-3):212-9. doi: 10.1016/j.forsciint.2013.09.015. Epub 2013 Sep 19.
Adult flies of some species are known to be attracted to crime scenes where they feed on the proteinaceous decomposition products of dead bodies. The flies leave deposits through excretion and regurgitation, and these artifacts often appear morphologically similar to bloodstains. To date, little consideration has been given to the possibility of the fly artifacts containing forensically useful levels of human DNA, or of flies as vectors of human DNA. In the present study, groups of artifacts collected after the adult blowfly Lucilia cuprina fed on biological fluids were examined and found to contain human DNA sufficient for profiling. Random samples from each group of artifacts were then subjected to human DNA profiling. Of the samples analysed, full or partial human DNA profiles were found in 57% of samples deposited by flies after blood meals, 92% after semen meals, 46% after saliva meals, 93% after blood/semen meals, 58% after blood/saliva meals and 95% after semen/saliva meals. DNA from artifacts deposited after flies were fed blood, semen, saliva, blood/semen, blood/saliva or semen/saliva was extracted at various time points up to 750 days, and the human DNA component quantified. The human DNA extracted from blood- and semen-based fly artifacts demonstrated a clear trend in which the amount of DNA extracted increased over the first 400 days, and full human DNA profiles were still obtained 750 days after artifact deposition. Saliva- and blood/saliva-based samples were tested at intervals up to 60 days and generated partial profiles at this final time. Blood/semen- and semen/saliva-based samples generated full profiles at 250 days. The presence of human DNA in fly artifacts has considerable forensic significance. Fly artifacts could potentially compromise crime reconstruction, and/or contaminate DNA evidence, up to at least two years after their deposition. Alternatively, fly artifacts may be a useful source of DNA if an offender has attempted to clean up a crime scene.
已知某些物种的成年蝇会被吸引到犯罪现场，在那里它们以尸体的蛋白质分解产物为食。苍蝇通过排泄和反刍留下沉积物，这些人工制品在形态上通常与血迹相似。迄今为止，人们很少考虑苍蝇人工制品是否可能含有法医学上有用水平的人类 DNA，或者苍蝇是否是人类 DNA 的载体。在本研究中，检查了成年丽蝇在吸食生物体液后收集的一组人工制品，并发现其中含有足够进行个体识别的人类 DNA。然后对每组人工制品的随机样本进行了人类 DNA 个体识别分析。在分析的样本中，在蝇类吸食血液后留下的样本中，有 57%的样本、在吸食精液后留下的样本中有 92%、在吸食唾液后留下的样本中有 46%、在吸食血液/精液后留下的样本中有 93%、在吸食血液/唾液后留下的样本中有 58%、在吸食精液/唾液后留下的样本中有 95%，发现了完整或部分的人类 DNA 图谱。从吸食血液、精液、唾液、血液/精液、血液/唾液或精液/唾液后的苍蝇留下的人工制品中提取 DNA，并在 0 至 750 天的不同时间点定量提取的人类 DNA 成分。从基于血液和精液的蝇类人工制品中提取的人类 DNA 显示出一个明显的趋势，即在最初的 400 天内提取的 DNA 量增加，并且在人工制品沉积 750 天后仍能获得完整的人类 DNA 图谱。唾液和血液/唾液样本在最后一次测试时每隔 60 天进行测试，在此最后时间点生成部分图谱。血液/精液和精液/唾液样本在 250 天时生成完整图谱。苍蝇人工制品中存在人类 DNA 具有重要的法医学意义。苍蝇人工制品可能会对犯罪重建产生影响，并且/或者在其沉积后至少两年内污染 DNA 证据。或者，如果犯罪者试图清理犯罪现场，苍蝇人工制品可能是 DNA 的有用来源。
