Contrasting Rates of Mitochondrial Molecular Evolution in Parasitic Diptera and Hymenoptera

Abstract

We investigated the putative association between the parasitic lifestyle and an accelerated rate of mt genetic divergence, compositional bias, and gene rearrangement, employing a range of parasitic and nonparasitic Diptera and Hymenoptera. Sequences were obtained for the cox1, cox2, 16S, 28S genes, the regions between the cox2 and atp8 genes, and between the nad3 and nad5 genes. Relative rate tests indicated generally that the parasitic lifestyle was not associated with an increased rate of genetic divergence in the Diptera but reaffirmed that it was in the Hymenoptera. Similarly, a departure from compositional stationarity was not associated with parasitic Diptera but was in parasitic Hymenoptera. Finally, mitochondrial (mt) gene rearrangements were not observed in any of the dipteran species examined. The results indicate that these genetic phenomena are not accelerated in parasitic Diptera compared with nonparasitic Diptera. A possible explanation for the differences in the rate of mt molecular evolution in parasitic Diptera and Hymenoptera is the extraordinary level of radiation that has occurred within the parasitic Hymenoptera but not in any of the dipteran parasitic lineages. If speciation events in the parasitic Hymenoptera are associated with founder events, a faster rate of molecular evolution is expected. Alternatively, biological differences between endoparasitic Hymenoptera and endoparasitic Diptera may also account for the differences observed in molecular evolution.

Molecular Characterization of Host-Specific Raphidascaridoid Worms from the Gangetic Garfish (Teleostomi: Belonidae) in India

“…However, the divergence in GC content was the highest at first position in ITS1 and ITS2 genes. The association of the augmented genetic divergence with level of radiation that occurred in parasites, as the parasitic life cycle progressed, was advocated in earlier studies [58]. The mitochondrial molecular divergence of G+C content, noticeably different from ITS1, ITS2 and 18S rDNA genes, as recorded in the present investigations, were linked to the extraordinary level of radiation that occurred in parasitic organisms [59].…”

Genetic aspects of mitochondrial genome evolution

“…It is unclear at present, which one is cause and which one is effect. Parasitic life styles seems to have an accelerating effect on the mutation rates (Castro et al, 2002).…”

Phylogeny of European Dolichopus and Gymnopternus (Diptera: Dolichopodidae) and the significance of morphological characters inferred from molecular data

“…Unsurprisingly, this low resolution did not allow them to draw conclusions about relationships within the Dolichopodidae. Castro et al (2002), Han et al (2002), and Moulton & Wiegmann (2004) included sequence data from single dolichopodid species in their investigations. Masunaga (1999) combined morphological and molecular data (ITS 1 and ITS 2, unfortunately not yet available in GenBank) to investigate the relationships between marine dolichopodid species.…”