Parasitology

Research Article

Characterization of the mitochondrial genome of Diphyllobothrium latum (Cestoda: Pseudophyllidea) – implications for the phylogeny of eucestodes

J.-K. PARKa1 c1, K.-H. KIMa1a4, S. KANGa1, H. K. JEONa1, J.-H. KIMa2, D. T. J. LITTLEWOODa3 and K. S. EOMa1

a1 Department of Parasitology, College of Medicine, Chungbuk National University Cheongju, Chungbuk 361-763, Republic of Korea

a2 Faculty of Marine Bioscience and Technology, Kangnung National University, Kangnung City, Kangwon-do 210-702, Republic of Korea

a3 Department of Zoology, Natural History Museum, Cromwell Road, London SW7 5BD, UK

a4 Present address: Korea Food and Drug Administration, Seoul 122-704, Republic of Korea.

SUMMARY

The complete nucleotide sequence of the mitochondrial genome was determined for the fish tapeworm Diphyllobothrium latum. This genome is 13 608 bp in length and encodes 12 protein-coding genes (but lacks the atp8), 22 transfer RNA (tRNA) and 2 ribosomal RNA (rRNA) genes, corresponding to the gene complement found thus far in other flatworm mitochondrial (mt) DNAs. The gene arrangement of this pseudophyllidean cestode is the same as the 6 cyclophyllidean cestodes characterized to date, with only minor variation in structure among these other genomes; the relative position of trnS2 and trnL1 is switched in Hymenolepis diminuta. Phylogenetic analyses of the concatenated amino acid sequences for 12 protein-coding genes of all complete cestode mtDNAs confirmed taxonomic and previous phylogenetic assessments, with D. latum being a sister taxon to the cyclophyllideans. High nodal support and phylogenetic congruence between different methods suggest that mt genomes may be of utility in resolving ordinal relationships within the cestodes. All species of Diphyllobothrium infect fish-eating vertebrates, and D. latum commonly infects humans through the ingestion of raw, poorly cooked or pickled fish. The complete mitochondrial genome provides a wealth of genetic markers which could be useful for identifying different life-cycle stages and for investigating their population genetics, ecology and epidemiology.

(Received September 29 2006)

(Revised October 17 2006)

(Accepted October 25 2000)

(Online publication January 11 2007)

Correspondence:

c1 *Corresponding author: Department of Parasitology, College of Medicine, Chungbuk National University Cheongju, Chungbuk 361-763, Republic of Korea. Tel: 82 43 261 2843. Fax: 82 43 272 1603. E-mail: jkpyou@chungbuk.ac.kr

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