Do longer sequences improve the accuracy of identification of forensically important Calliphoridae species?

Sara Bortolini; Giorgia Giordani; Fabiola Tuccia; Lara Maistrello; Stefano Vanin

doi:10.7717/peerj.5962

Do longer sequences improve the accuracy of identification of forensically important Calliphoridae species?

PeerJ. 2018 Dec 17:6:e5962. doi: 10.7717/peerj.5962. eCollection 2018.

Authors

Sara Bortolini¹, Giorgia Giordani², Fabiola Tuccia², Lara Maistrello¹, Stefano Vanin²

Affiliations

¹ Department of Life Sciences, University of Modena and Reggio Emilia, Reggio Emilia, Italy.
² School of Applied Sciences, University of Huddersfield, Huddersfield, United Kingdom.

Abstract

Species identification is a crucial step in forensic entomology. In several cases the calculation of the larval age allows the estimation of the minimum Post-Mortem Interval (mPMI). A correct identification of the species is the first step for a correct mPMI estimation. To overcome the difficulties due to the morphological identification especially of the immature stages, a molecular approach can be applied. However, difficulties in separation of closely related species are still an unsolved problem. Sequences of 4 different genes (COI, ND5, EF-1α, PER) of 13 different fly species collected during forensic experiments (Calliphora vicina, Calliphora vomitoria, Lucilia sericata, Lucilia illustris, Lucilia caesar, Chrysomya albiceps, Phormia regina, Cynomya mortuorum, Sarcophaga sp., Hydrotaea sp., Fannia scalaris, Piophila sp., Megaselia scalaris) were evaluated for their capability to identify correctly the species. Three concatenated sequences were obtained combining the four genes in order to verify if longer sequences increase the probability of a correct identification. The obtained results showed that this rule does not work for the species L. caesar and L. illustris. Future works on other DNA regions are suggested to solve this taxonomic issue.

Keywords: COI; Diptera; EF-1α; Maximum-likelihood; ND5; PER; Phylogeny.

Grants and funding

Giorgia Giordani and Fabiola Tuccia were supported by the Leverhulme trust scholarship. Sara Bortolini was supported by the “Finanziamento di azioni di mobilita’ nell’ambito del programma di collaborazione scientifica e culturale dell’Universita’ di Modena e Reggio Emilia con universita’ straniere convenzionate 2013–2014”. There was no additional external funding received for this study. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.