Wolbachia infection and mitochondrial diversity in the canine heartworm (Dirofilaria immitis).

BACKGROUND AND AIMS: Many species of filarial nematodes are infected with Wolbachia pipientis, a maternally inherited endosymbiont. In addition to manipulating host reproduction, these bacteria also affect the evolution of the mitochondrial DNA with which they are transmitted. Selective sweeps can establish a single mitochondrial lineage within a Wolbachia-infected population and purge genetic diversity. While this phenomenon has been studied in insect model systems, it has not been thoroughly examined in a filarial nematode.

MATERIALS AND

METHODS

Patterns of mitochondrial diversity were examined in Dirofilaria immitis, a Wolbachia-infected species.

RESULTS

The levels of genetic diversity observed in canine heartworm were much lower than those in related species not known to be hosts of Wolbachia.

CONCLUSION

RESULTS suggest that a maternally inherited endosymbiont can depress mitochondrial diversity in a filarial host.