Parasitology

Original Articles

A phylogeny of members of the family Taeniidae based on the mitochondrial cox1 and nad1 gene data

A. LAVIKAINENa1 c1, V. HAUKISALMIa2, M. J. LEHTINENa1, H. HENTTONENa2, A. OKSANENa3 and S. MERIa1a4

a1 Department of Bacteriology and Immunology, Haartman Institute, P.O. Box 21, FI-00014 University of Helsinki, Finland

a2 Vantaa Research Unit, Finnish Forest Research Institute, P.O. Box 18, FI-01301 Vantaa, Finland

a3 Fish and Wildlife Health Research Unit, Finnish Food Safety Authority Evira, P.O. Box 517, FI-90101 Oulu, Finland

a4 Helsinki University Central Hospital, P.O. Box 400, FI-00029 HUS, Finland

SUMMARY

The cestode family Taeniidae consists of 2 genera, Taenia and Echinococcus, which both have been the focus of intensive taxonomic and epidemiological studies because of their zoonotic importance. However, a comprehensive molecular phylogeny of this family has yet to be reconstructed. In this study, 54 isolates representing 9 Taenia species were characterized using DNA sequences in the mitochondrial cytochrome c oxidase subunit 1 (cox1) and NADH dehydrogenase subunit 1 (nad1) genes. Phylogenetic relationships within the family Taeniidae were inferred by combining cox1 and nad1 sequence data of the present and previous studies. In the phylogenetic analysis, the genus Echinococcus was shown to be monophyletic, but Taenia proved to be paraphyletic due to the position of T. mustelae as a probable sister taxon of Echinococcus. This indicates that T. mustelae should form a genus of its own. Taenia ovis krabbei was placed distant from T. ovis ovis, as a sister taxon of T. multiceps, supporting its recognition as a distinct species, T. krabbei. High intraspecific sequence variation within both T. polyacantha and T. taeniaeformis suggests the existence of cryptic sister species.

(Received May 29 2008)

(Revised July 27 2008)

(Accepted July 31 2008)

Correspondence:

c1 Corresponding author: Department of Bacteriology and Immunology, Haartman Institute, P.O. Box 21, FI-00014 University of Helsinki, Finland. Tel: +358919126891. Fax: +358919126382. E-mail: antti.lavikainen@helsinki.fi

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