DNA barcoding of forensically important flies in the Western Cape, South Africa

Abstract

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.

Morphological and Molecular Characterization of Forensically Important Blow Fly <i>Chrysomya megacephala</i> (F.)

“…Since, morphological identification can be challenging and at times unattainable due to resemblances among species, particularly in immature stages and sometimes in adults too (Harvey et al, 2003;Cooke et al, 2018), molecular identification of the fly was also carried out in the present study. PCR amplification of COI of C. megacephala was amplified using specific primers which resulted in amplicon of 700 bp.…”

Random forests for predicting species identity of forensically important blow flies (Diptera: Calliphoridae) and flesh flies (Diptera: Sarcophagidae) using geometric morphometric data: Proof of concept

“…This method commonly uses sequences from genes in the mitochondrial genome, such as the cytochrome c oxidase gene subunit I (COI) and II (COII), and the tRNA leucine gene, as markers for distinguishing sarcophagid fly species [9]. The internal transcribed spacer (ITS2) sequence sandwiched between the 5.8S and 28S rRNA genes has also been reported to be useful for identification of Calliphoridae species [10,11]. Wells & Sperling [12] and Wells et al [13] showed that COI, COII, and tRNA leucine sequences enable unambiguous identification of forensically important Calliphoridae and Sarcophagidae species.…”

Comparative Analysis of Molecular Identification and Wing Morphometrics of Forensically Important Blow Flies in China

“…In addition, many studies have proved the effectiveness of COI barcodes for the identi cation of many species of Calliphoridae [13,14]. Meanwhile, in GenBank, there are abundant molecular data about Calliphora, sequences of forensic important Calliphora have been published and uploaded online from different regions of the world, such as South Africa, the Caribbean Region, Southern European, the United States and Korea [15,16,17,18], making it possible to systematically study the sequence of Calliphora around the world. However, the molecular identi cation is a destructive approach for sample materials.…”