2000 Fiscal Year Final Research Report Summary
mechanisms of sympatric speciation in monophagous sawflies
| Project/Area Number |
11833010
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Institution | KOBE UNIVERSITY |
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Principal Investigator |
NAITO Tikahiko Kobe University, Faculty of Agriculture, Professor, 農学部, 教授 (70031226)
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| Co-Investigator(Kenkyū-buntansha) |
OISHI Kugao Kobe University, Faculty of Science, Professor, 理学部, 教授 (80030782)
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| Project Period (FY) |
1999 – 2000
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| Keywords | Sympatric speciation / Hemitaxonus / host shift / molecular evolution / Loderus genucinctus / Karyotype rearrangement / Neodiprion sertifer / 性フェロモン |
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| Research Abstract |
1.Sympatric speciation with host shift was investigated in the fern associated sawfly genus Hemitaxonus. (1) In H.japonicus complex, sympatric speciation is occurring in the narrow region around 34° N in Japan. (2) H.japonicus and H.sasayamensis, sibling species separated by sympatric speciation, show temporal isolation almost over their distributional ranges. (3) Two sibling species, H.athrii and H.takeuchii, are completely isolated geographically after sympatric speciation.
2.Phylogenetic relationships among the local populations of H.japonicus complex and H.sasayamensis were analyzed by comparing 547 nucleotide sequences of the mitochondrial gene coding CO II.Their molecular phylogenetic trees revealed that the host races of H.japonicus complex and local populations of H.sasayamensis formed distinct clusters, though these two siblings were not separated morphologically. The relationship between genetic variation and the process of sympatric speciation in H.japonicus complex was not clear.
3.The horsetail sawfly Loderus genucinctus had three intraspecific karyotype variation in a haploid set : n=9, n=10 and n=11, due to Robertsonian rearrangement. A presumably ancestral type n=9 is widely distributed in Japan except for Kinki and Chubu districts, where the derived types n=10 and n=11 are distributed. Such parapatric distribution of karyotypes may be due to the lower fitness of heterozygotes than homozygotes under the sympatric condition.
4.Holearctic pine sawfly Neodiprion sertifer showed considerable geographical variation of sex pheromone, which may cause the development of reproductive isolation among local population.
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Research Products
(8 results)
