Department of Neuroscience, Università Politecnica delle Marche, Ancona, Italy.
Forensic Sci Int. 2010 Feb 25;195(1-3):99-102. doi: 10.1016/j.forsciint.2009.11.022. Epub 2010 Jan 19.
Puparial cases are common remnants of necrophagous flies in crime investigations. They usually represent the longest developmental time and, therefore, they can be very useful for the estimation of the post-mortem interval (PMI). However, before any PMI estimate, it is crucial to identify the species of fly eclosed from each puparium associated with the corpse. Morphological characteristics of the puparium are often distinctive enough to permit a species identification. But, even an accurate morphological analysis of empty puparia cannot discriminate among different species of closely related flies. Furthermore, morphological identification may be impossible if the fly puparia are poorly preserved or in fragments. This study explores the applicability of biomolecular techniques on empty puparia and their fragments for identification purposes. A total of 63 empty puparia of necrophagous Diptera resulting from forensic casework were examined. Samples were divided into three groups according to size, type and time of eclosion in order to verify whether the physical characteristics and puparia weathering can influence the amount of DNA extraction. The results suggest that a reliable genetic identification of forensically important flies may also be performed from empty puparia and/or their fragments. However, DNA degradation can deeply compromise the genetic analysis since the older the fly puparia, the smaller are the amplified fragments.
蛹壳是法医学调查中常见的腐食性蝇类的残余物。它们通常代表着最长的发育时间，因此对于推断死后经过时间（PMI）非常有用。然而，在进行任何 PMI 估计之前，确定与尸体相关的每个蛹壳中羽化出的蝇种至关重要。蛹壳的形态特征通常足以进行物种鉴定。但是，即使对空蛹壳进行准确的形态分析，也无法区分密切相关的蝇种。此外，如果蝇蛹壳保存不善或已破碎，形态识别可能是不可能的。本研究探讨了生物分子技术在空蛹壳及其碎片上的应用，以进行鉴定。共检查了 63 个来自法医工作的腐食性双翅目空蛹壳。根据羽化时的大小、类型和时间，将样本分为三组，以验证物理特征和蛹壳风化是否会影响 DNA 提取量。结果表明，即使是空蛹壳和/或其碎片也可以可靠地进行法医学上重要的蝇种的基因鉴定。然而，由于蝇蛹壳越老，扩增片段越小，因此 DNA 降解会严重影响遗传分析。
