| Project/Area Number |
16406010
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 海外学術 |
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| Research Field |
Parasitology (including Sanitary zoology)
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| Research Institution | Kochi University |
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Principal Investigator |
AGATSUMA Takeshi Kochi University, Dept of Environmental Health Science, Professor (40117031)
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| Co-Investigator(Kenkyū-buntansha) |
HIRAI Hirohisa Kyoto University, Primate Research Institute, Professor (10128308)
TAGUCHI Takahiro Kochi University, Graduate School of Kuroshio Science Doctoral Course, Assistant Professor (80127943)
AGATSUMA Yoshiko Kochi Gakuen College, Dept of Medical Technology, Professor (50004726)
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| Project Period (FY) |
2004 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥13,100,000 (Direct Cost: ¥13,100,000)
Fiscal Year 2006: ¥4,500,000 (Direct Cost: ¥4,500,000)
Fiscal Year 2005: ¥4,200,000 (Direct Cost: ¥4,200,000)
Fiscal Year 2004: ¥4,400,000 (Direct Cost: ¥4,400,000)
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| Keywords | Schistosoma japonicum / Schistosomatidae / Molecular phylogeny / Chromosome Microdissection / Genome mapping / Gene arrangements / Origin of Schistosoma / Coevolution / ミトコンドリアDNA / 核DNA / 染色体 / 分子系藤樹 / 分子進化 / 種分化 / 分子生物地理 / 住血吸虫 / 遺伝子配置 / 肝臓超音波検査 / Network pattern / Orientobilharzia |
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| Research Abstract |
In this study, analyses for DNA sequences, mitochondrial (mt) DNA gene arrangements and chromosome mapping were carried out in order to verify the African origin theory of Schistosoma japonicum by Davis (1980, 1992). Our research to date reached the conclusion of the Asia origin theory, on the contrary. However, it is yet uncertain when and how 'Out of Asia' was possible for them to perform. It was also suggested from our studies that some members of the S. indicum group reintroduced from Africa to Asia, but it is also yet unknown about the rout and time of remigration. In this study, from the viewpoint of intra-specific variations, frequencies and geographic distributions of haplotypes in the CO1 region of the mt DNA were investigated in the S. indicum group. Two different haplotypes, that considerably differ from each other in sequence, were found in S. sindale from Bangladesh. The one from Bangladesh formed a cluster with that of S. sindale from Malaysia and Sri Lanka. The other fro
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m Bangladesh formed a cluster with that of S. sindale from Thailand. The difference in the DNA sequence between the two haplotypes corresponds with that between independent species. In addition, one of the hot regions (ND4-ND1) in the mt DNA gene arrangement of Schistosoma was analyzed for the first time using S. nasale, S. incognitum and S. bovis. As a result, it was clarified that these 3 species from Asia and Africa all turned out to be of the African type. A phylogenetic analysis using DNA sequences from each region as well as concatenated sequences including the three regions in the ND4-ND1 region plus the CO1 region was also carried out in order to confirm the taxonomical position of S. incognitum. The former analysis showed a rather unstable trees, but the latter revealed stable and congruent trees especially in terms of phylogenetic relationships between genera as well as species. Under these investigations, it was discovered that S. incognitum diverged earliest from the common ancestral species of the African group and the S. indicum group. Therefore, the result denies the idea that S. incognitum diverged from a common ancestor of the S. japonicum group. Less
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