| Project/Area Number |
10041161
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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 |
遺伝
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| Research Institution | TOKYO INSTITUTE OF TECHNOLOGY |
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Principal Investigator |
OKADA Norihiro Tokyo Institute of Technology Professor Graduate School of Biosciense & Biotechnology, 大学院・生命理工学研究科, 教授 (60132982)
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| Co-Investigator(Kenkyū-buntansha) |
OHSHIMA Kazuhiko Tokyo Institute of Technology Associate Professor Graduate School of Biosciense & Biotechnology, 大学院・生命理工学研究科, 講師 (60282852)
YUMA Masahide Kyoto University Associate Professor Center for Ecological Research, 生態学研究センター, 助教授
NISHIDA Mutsumi University of Tokyo Professor Division of Moleculer Marine Biology, Ocean Research Institute, 海洋研究所, 教授
TAKAHASHI Kazuhiko Tokyo Institute of Technology Research Assistant Graduate School of Bioscience & Biotechnology, 大学院・生命理工学研究科, 助手 (40302955)
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| Project Period (FY) |
1998 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥9,800,000 (Direct Cost: ¥9,800,000)
Fiscal Year 2000: ¥2,700,000 (Direct Cost: ¥2,700,000)
Fiscal Year 1999: ¥3,300,000 (Direct Cost: ¥3,300,000)
Fiscal Year 1998: ¥3,800,000 (Direct Cost: ¥3,800,000)
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| Keywords | Lake Victoria / Lake Malawi / Lake Tanganyika / Cichlid fish / Adaotive radiation / phylogeny / Cichlidae / SINE / レトロポゾン / アフリカ / マラウィ湖 / PCR |
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| Research Abstract |
Lake Tanganyika harbors numerous endemic species of extremely diverse cichlid fish that have been classified into twelve major taxonomic groups known as tribes. Analysis of SINE insertion data has been acknowledged as a powerful tool for the elucidation of phylogenetic relationships, and we applied this method in an attempt to clarify such relationships among these cichlids. We studied insertion patterns of 38 SINEs in total, 24 of which supported the monophyly of three clades. The other 14 loci revealed extensive incongruence in terms of the patterns of SINE insertions. These incongruence most likely stems from period of adaptive radiation. One possible explanation for this phenomenon in the extensive incomplete lineage sorting of alleles for the presence or absence of a SINE during successive speciation events during this period which took place about 5-10 million years ago.
Lake Malawi is home to more than 450 species of endemic cichlids, which provide a spectacular example of adaptive radiation. We identified six loci at which a SINE sequence had apparently been specifically inserted by retroposition in the common ancestor of all the investigated species of endemic cichlids in Lake Malawi. At another locus, unique sharing of a SINE sequence was evident among all the investigated species of endemic non-Mbuna cichlids with the exception of Rhamphochromis sp. We also characterized a locus that exhibited transspecies polymorphism with respect to the presence or absence of the SINE sequence among non-Mbuna species. This result suggests that incomplete lineage sorting and/or interspecific hybridization might have occurred or be occurring among the species in this group, which might potentially cause misinterpretation of phylogenetic data, in particular when a single-locus marker, such as a sequence in the mitochondrial DNA, is used for analysis.
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