The mitochondrial control region of blowflies (Diptera: Calliphoridae): a hot spot for mitochondrial genome rearrangements.

The family Calliphoridae consists of myiasis-causing flies, including species of economic, forensic, and medical importance. In this study, the complete control regions (CRs) of mitochondrial DNA from 15 calliphorid species were sequenced and structurally characterized. The CRs had a high content of adenines (A) and thymines (T) and varied in length from 854 to 2,018 bp, showing intraspecific variations in sequence and length. Two major domains were identified: the conserved domain containing conserved sequence blocks and cis-regulatory structures that may be related to the transcription and the origin of replication of mitochondrial DNA, and the variable domain, containing high sequence and length variation. Within the variable domain, duplication of the tRNA(Ile) gene, previously reported for three Chrysomya species, was identified in two more species of this genus and in two species of two other genera. The structural characterization shows the plasticity of the mitochondrial genome in dipterans. The organizational similarities of the duplicated region found in different species and the possible origin of the duplicated genes are discussed.