Identification of Forensically Important Calliphoridae and Sarcophagidae Species Collected in Korea Using SNaPshot Multiplex System Targeting the Cytochrome c Oxidase Subunit I Gene.

Ji Hye Park,Seong Hwan Park,Sang Eon Shin,Kwang Soo Ko

doi:10.1155/2018/2953892

Ji Hye Park, Seong Hwan Park + Show 2 more

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https://doi.org/10.1155/2018/2953892

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Abstract

Estimation of postmortem interval (PMI) is paramount in modern forensic investigation. After the disappearance of the early postmortem phenomena conventionally used to estimate PMI, entomologic evidence provides important indicators for PMI estimation. The age of the oldest fly larvae or pupae can be estimated to pinpoint the time of oviposition, which is considered the minimum PMI (PMImin). The development rate of insects is usually temperature dependent and species specific. Therefore, species identification is mandatory for PMImin estimation using entomological evidence. The classical morphological identification method cannot be applied when specimens are damaged or have not yet matured. To overcome this limitation, some investigators employ molecular identification using mitochondrial cytochrome c oxidase subunit I (COI) nucleotide sequences. The molecular identification method commonly uses Sanger's nucleotide sequencing and molecular phylogeny, which are complex and time consuming and constitute another obstacle for forensic investigators. In this study, instead of using conventional Sanger's nucleotide sequencing, single-nucleotide polymorphisms (SNPs) in the COI gene region, which are unique between fly species, were selected and targeted for single-base extension (SBE) technology. These SNPs were genotyped using a SNaPshot® kit. Eleven Calliphoridae and seven Sarcophagidae species were covered. To validate this genotyping, fly DNA samples (103 adults, 84 larvae, and 4 pupae) previously confirmed by DNA barcoding were used. This method worked quickly with minimal DNA, providing a potential alternative to conventional DNA barcoding. Consisting of only a few simple electropherogram peaks, the results were more straightforward compared with those of the conventional DNA barcoding produced by Sanger's nucleotide sequencing.

Highlights

Estimation of postmortem interval (PMI) is important in unusual death cases
Medicolegal entomology focuses primarily on providing evidence of the amount of time during which a corpse or carcass has been exposed to colonization by insects, which helps to estimate the minimum postmortem interval (PMImin) [2, 3]
Complete mitochondrial c oxidase subunit I (COI) gene sequences from 18 fly species were collected from GenBank (Table 1)

Summary

Introduction

Estimation of postmortem interval (PMI) is important in unusual death cases. Estimation of PMI using insects is important for late postmortem changes. Medicolegal entomology focuses primarily on providing evidence of the amount of time during which a corpse or carcass has been exposed to colonization by insects, which helps to estimate the minimum postmortem interval (PMImin) [2, 3]. Forensically important fly families include Calliphoridae, Sarcophagidae, Muscidae, and Piophilidae [5]. According to the first survey of forensically important entomofauna collected from medicolegal autopsies in South Korea, the predominant family of necrophagous flies was Calliphoridae and the second Sarcophagidae [6]. We selected 11 Calliphoridae and 7 Sarcophagidae species mainly based on the list from a previous study in South Korea [7]. One Sarcophagidae species, S. crassipalpis, was added based on the literature [6, 8]

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