Division of Forensic Medicine and Toxicology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Anzio Road, Observatory, Cape Town, South Africa.
Genome. 2018 Dec;61(12):823-828. doi: 10.1139/gen-2018-0054. Epub 2018 Oct 2.
Forensic entomology aids the determination of post mortem interval based on arthropods associated with a deceased body. This relies on the accurate identification of insects that visit the body, particularly first colonisers such as Calliphoridae (Diptera). Traditional species identification though morphological keys can be challenging as immature or closely related specimens can look similar. Some of these challenges have been overcome through "DNA barcoding", which involves the sequencing of informative regions within a species' DNA and comparison to a database of reference sequences. However, reference DNA sequences of blow fly species in South Africa is currently limited. In this study, adult blow flies representing four species common to the Western Cape, South Africa (Chrysomya chloropyga, Chrysomya albiceps, Chrysomya marginalis, Lucilia sericata) were examined using morphological keys and DNA barcoding of two regions: COI and ITS2. These DNA sequences were then used as references for the successful identification of seven unknown immature specimens. Intraspecific divergence showed a maximum of 0.36% and 2.25% for COI and ITS2, respectively; interspecific divergence showed a minimum of 6.14% and 64.6% for COI and ITS2, respectively. According to these results, COI and ITS2 have sufficient discriminatory power for species-level identification for the four species studied.
法医昆虫学有助于根据与死者尸体有关的节肢动物来确定死后间隔时间。这依赖于对访问尸体的昆虫的准确识别，特别是第一殖民者，如丽蝇科（双翅目）。尽管通过形态学钥匙进行传统的物种鉴定可能具有挑战性，因为未成熟或密切相关的标本看起来可能相似。这些挑战中的一些已经通过“DNA 条形码”得到了克服，它涉及对物种 DNA 内的信息区域进行测序，并与参考序列数据库进行比较。然而，南非的丽蝇物种的参考 DNA 序列目前是有限的。在这项研究中，代表南非西开普省（南非）四种常见的成虫蝇（Chrysomya chloropyga、Chrysomya albiceps、Chrysomya marginalis、Lucilia sericata）进行了检查，使用形态学钥匙和两个区域的 DNA 条形码：COI 和 ITS2。然后，将这些 DNA 序列用作成功识别七个未知的未成熟标本的参考。种内差异显示 COI 和 ITS2 分别最大为 0.36%和 2.25%；种间差异显示 COI 和 ITS2 分别最小为 6.14%和 64.6%。根据这些结果，COI 和 ITS2 对于所研究的四种物种具有足够的种间识别能力。
