Government of Nepal

Ministry of Education, Science and Technology

National Forensic Science Laboratory

DNA-based identification of forensically important species of Sarcophagidae (Insecta: Diptera) from Rio de Janeiro, Brazil

Flies represent the most important insect order used for forensic purposes, especially because members of the Calliphoridae, Muscidae, and Sarcophagidae families are the first and most frequent colonizers of corpses (Smith, 1986). Morphological examination is used to identify characteristics of the male genitalia, and there are few taxonomic features that canbe easily used by non-specialists for species identification (Carvalho and Mello-Patiu, 2008; Giroux et al., 2010). Furthermore, few tools are available for the identification of forensically important fly species (Giroux et al., 2010) and these are constantly outdated in regions where the diverse insect fauna is understudied. These difficulties limit the use of entomological data by the forensic investigator.

Sarcophagid flies (flesh flies) are potentially useful dipterans for forensic purposes because most of these species have necrophagous larvae. However, their performance has been underestimated because most individuals that are attracted to carcasses are females, which use them to lay larvae (Byrd and Castner, 2011). The identification of females and immature flies is difficult because of their conservative morphology and there are very few or no morphological differences between species.

As compared with Calliphoridae, only a few studies on community succession on carcasses in Brazil have included data on Sarcophagidae (Moura et al., 1997; Carvalho et al.,2000; Carvalho et al., 2004; Barbosa et al., 2009) in Rio de Janeiro (Barbosa et al., 2009). Some species have been suggested as possible indicators for forensic purposes, including: Oxysarcodexia fluminensis (Lopes, 1946), Peckia (Pattonella) intermutans (Walker, 1861), and Peckia (Peckia) chrysostoma (Wiedemann, 1830).
DNA-based techniques have been used as successful alternatives to morphological examination for taxonomic identification of species of forensic interest (Wells et al., 2001; Schroeder et al., 2003; Wells and Stevens, 2008; Saigusa et al., 2009; Meiklejohn et al., 2011; Tan et al., 2010; Guo et al., 2012). Molecular identification is advantageous because it can be applied to any stage of development and to adult flies of any gender. The large number of publicly available sequences of the mitochondrial gene cytochrome c oxidase subunit I (COI) gene has made this marker the most widely used in forensic studies.

Nevertheless, DNA-based identification relies on an extensive database of sequences derived from correctly identified individuals. Therefore, because no molecular data are available on Sarcophagidae from Rio de Janeiro, our goal was to analyze part of the mitochondrial COI DNA identification of Sarcophagidae from Rio de Janeiro 3 Genetics and Molecular Research 15 (2): gmr.15027705 ©FUNPEC-RP www.funpecrp.com.br gene from three Sarcophagidae species of forensic importance in the Rio de Janeiro County in order to initiate the formation of a molecular database for these species.

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