Species identification of the forensically important flies in Iwate prefecture, Japan based on mitochondrial cytochrome oxidase gene subunit I (COI) sequences

Molecular biological species identification of forensically important flies distributed in Iwate prefecture, Japan, was carried out, and the utility of this method was evaluated. The dipteran nymphs that were early colonizers on the corpse were reared to adult and morphologically identified. Meanwhile they were sequenced over a 304 base pair region of the mitochondrial cytochrome oxidase gene subunit I (COI). Six species belonging three genera of Calliphoridae (Calliphora lata, C. vicina, Lucilia cuprina, L. illustris, L. sericata, Chrysomya pinguis) and two species of Sarcophagidae (Parasarcophaga crassipalpis, P. similis) were collected and identified. Each fly had somewhat different ecological features such as seasonal dominance and habitat. The COI sequences of each species were unique and distinguishable from each other, although they showed high homology. Species identification from immature diptera by the DNA sequences was simple and time-saving because there was no need to wait for adult emergence or knowledge of morphological keys, and it provided information about not only postmortem interval but also seasonal and environmental conditions surrounding the corpse.