A molecular study of the forensically important calliphoridae (diptera): implications and applications for the future of forensic entomology

Michelle Harvey

    Research output: ThesisMaster's Thesis

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    Abstract

    [Truncated abstract] A common application of forensic entomology is the estimation of post-mortem interval (PMI). This is most frequently estimated from the age of calliphorid specimens collected from a corpse, and in many cases it is the immature stages that are encountered. A critical step in the estimation of PMI is the accurate identification of insects to species level, with misidentification potentially resulting in the application of unsuitable developmental data and therefore inaccuracy in the resulting estimate. Identification has long been attempted on a morphological basis, but complicated by the lack of larval keys to the Calliphoridae, limited diagnostic features in immature stages and the poor preservation of specimens. Standard practice in forensic entomology is the rearing of immatures collected from the corpse through to the more distinctive adult stages, however this process is time-consuming and may be hindered where specimens die during rearing. Furthermore, many cases are presented for forensic entomologist as an afterthought and specimens are already preserved. Consequently, a new approach to the identification of calliphorids is sought which will overcome the problems of the morphological and rearing methods. ... The culmination of this study is the consideration of applications of molecular data to forensic entomology. A sequence-specific priming (SSP) technique is presented for the identification of the forensically significant calliphorids of Australia and New Zealand, along with a new method for the extraction and storage of calliphorid DNA samples using Whatman FTA cards. These techniques will potentially improve the efficiency and accuracy of identification in the estimation of PMI using calliphorids. The use of calliphorid DNA is not limited to PMI estimation, but may also be applied to museum studies. DNA was extracted from pupal casings from 300 year old mummified corpses, however difficulty was encountered in amplifying the DNA reproducibly. This illustrates however, the wide-ranging implications of the calliphorid sequence data gathered in this study. This thesis makes a significant contribution to the consideration of the status of some global calliphorid species. The new technique presented for identification of Australian and New Zealand species is the culmination of an important body of data that will ultimately contribute to the strong foundation of forensic entomology and our future accuracy, efficiency and utility as a routine investigative tool.
    Original languageEnglish
    QualificationMasters
    Publication statusUnpublished - 2006

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