2006 Fiscal Year Final Research Report Summary
Study forf domestication process of the silkworm Bombyx mori based on results of the silkworm genome project
| Project/Area Number |
16380044
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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 | 一般 |
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| Research Field |
Applied entomology
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| Research Institution | National Institute of Agrobiological Sciences |
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Principal Investigator |
YUKUHIRO Kenji National Institute of Agrobiological Sciences, Insect Genome Research Unit, Senior Researcher, 昆虫科学研究領域・昆虫ゲノム研究・情報解析ユニット, 主任研究員 (50343992)
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| Co-Investigator(Kenkyū-buntansha) |
ITOH Masanobu Kyoto Institute of Technology, Dept.Applied Biology, Graduate School of Science and Technology, Associate Professor, 大学院・工芸科学研究科, 助教授 (60221082)
NAKAJIMA Yumiko University of the Ryukyus, Center of Molecular Biosciences, Associate Professor, 遺伝子実験センター, 助教授 (70244340)
BANNO Yutaka Kyushu University Graduate School, Institute of genetic resources, Silkworm Division, Associate Professor, 農学研究院・遺伝子資源開発研究センター, 助教授 (50192711)
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| Project Period (FY) |
2004 – 2006
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| Keywords | Bombyx mandarina / bombyx mori / transposable element / nucleotide polymorphism / chromosome number polymorphism / domestication / mariner-like-elements (MLEs) |
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| Research Abstract |
Nucleotide polymorphism of molybdenum cofactor sulfurase gene (og), mitochondrial cox 1 gene and fibroin heavy chain (FHC) intronic sequence were examined in Bombyx mori and Japanese B.mandarina. Five distinct og haplogroups were confirmed in B.mori, whereas insertion dimorphism based on two different insertions was observed and no identical sequence pairs were found in Japanese B.mandarina. Three coxl haplotypes were observed in B.mori, whereas two in Japanese B.mandarina, suggesting strong selective sweep on mitochondrial genotype. Analyzing FHC intronic sequences showed multiples haplotypes but low level of sequence variation in both species.
To evaluate the evolutionary relationship between B.mori and B.mandarina, we analyzed alkaline phosphatase (Alp) gene and found that Alp genes are duplicated in tandem in both species. Comparing their polymorphic intervening sequences suggested that the Alp gene cluster in B.mandarina inhabiting China would be the ancestral type. Phylogenetic tr
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ees from the two Alp genes both support above assumption.
Full-length MLEs termed Cecropia-ITR-MLEs and Bmmar6 were successfully isolated from Chinese, Korean and Japanese individuals of B.mandarina by the PCR using the inverted terminal repeat of the Hyalophora cecropia MLE and Bmmar6. By analyzing these sequences, B.mandarina Cecropia-ITR-MLE sequences could be divided into two major groups called the Continental and the Japanese type, respectively. The Japanese type tended to derived from Honshu specimens. Two possible horizontal transfer events were found in Japanese B.mandarina: One is common L1Bm-carrying MLE insertions. The other is distribution of nearly identical Bmmar 6 elements in some lepidopteran species other than Bombyx inhabiting Japan.
Chromosome numbers on B.mandarina collected in Japan and B.mori was cytogenetically analyzed. The chromosome number of B.mandarina from Hokkaido, Saitama, Nagano, Fukuoka, Nagasaki, was n=27, whereas all 17 strains in B.mori preserved at Kyushu University graduate school had n=28 chromosome constitution. Less
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