›› 2010, Vol. 28 ›› Issue (4): 3-256.

• 论著 • Previous Articles     Next Articles

Study on Molecular Phylogeny of Schistosoma bovis Based on Mitochondrial DNA Sequence and Gene Order

XIAO Jing-ying1，2，CAI Lian-shun2，Nagataki Mitsuru1，Tokuhiro Shinji1，Jarilla Blanca R.1，Shimada Masaaki3，David Blair4，Agatsuma Takeshi1 *   

  1. 1 Kochi Medical School，Kochi University，Kochi 783-5805，Japan；2 Basic Medical College，Jiamusi University，Jiamusi 154007，China；3 Institute of Tropical Medicine，Nagasaki University，Nagasaki 852-8523，Japan; 4 School of Tropical Biology，James Cook University，Townsville QLD 4811，Australia
  • Received:1900-01-01 Revised:1900-01-01 Online:2010-08-30 Published:2010-08-30

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Abstract: Objective To determine the nucleotide sequence of the partial mitochondrial （mt） genome and the order of the mitochondrial protein-coding genes for Schistosoma bovis for analysis of possible phylogenetic position of this species in the genus Schistosoma. Methods　 The genomic DNA of adult worms were extracted by the GNT-K method. The target regions were amplified by PCR using a degenerated primer and specific primer. The PCR products were purified before ligating into the pGEM1 T-vector system. Recombinant plasmids were amplified in Escherichia coli， extracted and purified using routine methods. The nucleotide sequences were determined with an ABI PRISM 3100-Avant DNA sequencer using a BigDye Terminators v3.1 Cycle Sequencing Kit （Applied Bio-systems， CA， USA） with two T-vector specific primers （T7 and SP6）. Positive colonies were sequenced with two internal specific primers to obtain the full sequence of each fragment on both strands by means of primer walking. Sequences of related schistosomes were retrieved from GenBank and aligned with our data. Gene trees were constructed using neighbor joining methods. 　 Results　 The nucleotide sequence was determined and the gene order of this region in S. bovis was found as follows: NADHdehydrogenase4（nad4）-trnQ （Gln）-trnK（Lys） -NADH dehydrogenase 3（nad3）-trnD （Asp）-NADH dehydrogenase 1（nad1）. The gene order covering such region of S. bovis was similar to that of the African Schistosoma species，but strikingly different from the Asian species. Phylogenetic trees inferred from the alignment including partial nad4，nad3，partial nad1 and partial nad4+nad3+nad1 sequence for other 8 Schistosoma spp., respectivly， revealed that S. bovis is placed proximally to S. haematobium in the African sub-group， which is identical with those placed by gene order in the African clade. Conclusion The mtDNA analysis based on mitochondrial DNA sequence and the gene order strongly support the hypothesis that S. bovis belongs to the African schistosome clade rather than the Asian Schistosoma species.

Key words: Schistosoma bovis, NADH dehydrogenase 4, NADH dehydrogenase 3, NADH dehydrogenase 1, Gene order, Phylogenetic relationship