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A molecular phylogeny of the genus Echinococcus

Published online by Cambridge University Press:  06 April 2009

J. Bowles
Affiliation:
Molecular Parasitology Unit, Tropical Health Program, The Queensland Institute of Medical Research, The Bancroft Centre, 300 Herston Road, Brisbane, Queensland 4029, Australia
D. Blair
Affiliation:
Department of Zoology, James Cook University, Townsville, Queensland 4811, Australia
D. P. McManus
Affiliation:
Molecular Parasitology Unit, Tropical Health Program, The Queensland Institute of Medical Research, The Bancroft Centre, 300 Herston Road, Brisbane, Queensland 4029, Australia

Summary

Three nucleotide data sets, two mitochondrial (COI and ND1) and one nuclear (ribosomal ITS1), have been investigated in order to resolve relationships among species and strains of the genus Echinococcus. The data have some unusual properties in that mitochondrial heteroplasmy was detected in one strain of E. granulosus, and more than one class of ITS1 sequence variant can occur in a single isolate. The data failed to support the hypothesis that E. granulosus, as it is currently viewed, is a single valid species. Rather, the strains of E. granulosus seem to comprise at least three evolutionarily diverse groups, the sheep strain group, bovine strain group and horse strain group. Molecular distances between them are comparable to, or greater than, molecular evolutionary distances observed between recognized species. The affinities of the cervid strain of E. granulosus are unclear because of ambiguous data, but this strain does not appear to be ancestral to others. E. multilocularis may not be distinct from E. granulosus. However, the remaining two species, E. vogeli and E. oligarthrus appear distinct and rather distant from the first two. Based on the results presented here, taxonomic revision of the genus is clearly warranted.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1995

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