title: Why is the molecular identification of the forensically important blowfly species Lucilia caesar and L. illustris (family Calliphoridae) so problematic?
abstract: Species of the fly genus Lucilia are commonly used in forensic investigations to estimate the postmortem interval (PMI). Two close-related species Lucilia caesar and L. illustris are difficult to identify. Previous studies showed that the mitochondrial cytochrome c oxidase subunit I (COI) marker could be used to identify many Lucilia species. However, mixed results were obtained for L. caesar and L. illustris due to some European specimens showing identical haplotypes. Here, we investigated 58 new European male specimens of L. illustris and L. caesar whose morphological identifications were checked and for which COI fragments were sequenced. In addition, two other mitochondrial (cytochrome c oxidase subunit II and 16S) and two nuclear (internal transcribed spacer 2 and 28S ribosomal RNA) markers were obtained for a subset of these samples. For each marker, genetic divergence within each species was in the same range as between species, confirming the close relationship between both species. Moreover, for each of the gene fragments, both species shared at least one haplotype/genotype. Hence, none of the molecular markers tested could be used, alone or in combination, to discriminate between L. illustris and L. caesar.
authors.affiliation: Joint Experimental Molecular Unit, Royal Museum for Central Africa, Leuvensesteenweg 13, 3080 Tervuren, Belgium. gontran.sonet@naturalsciences.be
authors.forename: Gontran
authors.initials: G
authors.lastname: Sonet
authors.forename: Kurt
authors.initials: K
authors.lastname: Jordaens
authors.forename: Yves
authors.initials: Y
authors.lastname: Braet
authors.forename: Stijn
authors.initials: S
authors.lastname: Desmyter
mesh_terms: D000818:Animals; D004272:DNA, Mitochondrial / Q000235:genetics*; D021903:DNA, Ribosomal Spacer / Q000235:genetics*; D004175:Diptera / Q000235:genetics*; D003576:Electron Transport Complex IV / Q000235:genetics*; D004772:Entomology / Q000379:methods; D044707:Forensic Sciences; D005819:Genetic Markers; D008297:Male; D016133:Polymerase Chain Reaction; D012336:RNA, Ribosomal, 16S / Q000235:genetics*; D012339:RNA, Ribosomal, 28S / Q000235:genetics*; D017421:Sequence Analysis
chemical_list: D004272:DNA, Mitochondrial; D021903:DNA, Ribosomal Spacer; D005819:Genetic Markers; D012336:RNA, Ribosomal, 16S; D012339:RNA, Ribosomal, 28S; D003576:Electron Transport Complex IV