Recent African derivation ofChrysomya putoriafromC. chloropygaand mitochondrial DNA paraphyly of cytochrome oxidase subunit one in blowflies of forensic importance

Abstract

Chrysomya chloropyga (Wiedemann) and C. putoria (Wiedemann) (Diptera: Calliphoridae) are closely related Afrotropical blowflies that breed in carrion and latrines, reaching high density in association with humans and spreading to other continents. In some cases of human death, Chyrsomya specimens provide forensic clues. Because the immature stages of such flies are often difficult to identify taxonomically, it is useful to develop DNA-based tests for specimen identification. Therefore we attempted to distinguish between C. chloropyga and C. putoria using mitochondrial DNA (mtDNA) sequence data from a 593-bp region of the gene for cytochrome oxidase subunit one (COI). Twelve specimens from each species yielded a total of five haplotypes, none being unique to C. putoria. Therefore it was not possible to distinguish between the two species using this locus. Maximum parsimony analysis indicated paraphyletic C. chloropyga mtDNA with C. putoria nested therein. Based on these and previously published data, we infer that C. putoria diverged very recently from C. chloropyga.

Validation of a DNA-based method for identifying Chrysomyinae (Diptera: Calliphoridae) used in a death investigation

“…The importance of defining a method like this in terms of geographic region is illustrated by the fact that COI data did not distinguish C. putoria from its sister species Chrysomya chloropyga [42]. These two flies are extremely closely related, resulting in a history of confusion concerning the taxonomic separation; however, they are clearly separate species with distinct bionomic traits [27].…”

“…Consequently, most authors have advocated the use of a region within COI + COII for forensic insect identification (e.g., [8,14,20,40]). However, some closely related species could not be distinguished using the COI + COII sequence [36,42]. Protocols are available for characterizing other mtDNA [37,43] or nuclear [26,30] loci in forensically important Diptera, and some of these may prove to be more useful than COI + COII for some taxa.…”

Using the Developmental GeneBicoidto Identify Species of Forensically Important Blowflies (Diptera: Calliphoridae)

“…Additionally, this kind of study may be extended to other confused taxa such as L. cuprina and some Chrysomya species [14–16]. This study is the first to use a renowned developmental gene, bicoid , in forensic science and entomology.…”

“…Since the conventional DNA markers have some limitations, new autosomal-based DNA markers for the identification of forensic insect species may ameliorate the problems associated with conventional markers. Among blowfly species, two Lucilia species ( L. illustris and caesar), two tropical Luciliinae species ( Lucilia cuprina and Hemipyrellia ligurriens ), and two African Chrysomya species ( C. putoria and C. chloropyga ) show species level paraphylies [14–16]. According to Zaidi et al, identification of closely related species may demand a multigene approach [17].…”

Identification of Forensically Important Sarcophagid Flies (Diptera: Sarcophagidae) in China, Based on COI and 16S rDNA Gene Sequences*

“…Even partial sequences of this COI gene have been proven to have sufficient discrimination power (2,4,15–18), which makes it, in particular, suitable for forensic applications. However, some closely related species failed to be discriminated by COI sequence analysis (19–22). The main limitation to the use of COI sequence data has been the inability to distinguish between some closely related species (23).…”