| Project/Area Number |
16K20875
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| Research Category |
Grant-in-Aid for Young Scientists (B)
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| Allocation Type | Multi-year Fund |
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| Research Field |
Animal physiology/Animal behavior
Developmental biology
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| Research Institution | Hokkaido University |
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Principal Investigator |
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| Project Period (FY) |
2016-04-01 – 2019-03-31
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| Project Status |
Completed (Fiscal Year 2018)
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| Budget Amount *help |
¥4,030,000 (Direct Cost: ¥3,100,000、Indirect Cost: ¥930,000)
Fiscal Year 2018: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2017: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000)
Fiscal Year 2016: ¥2,470,000 (Direct Cost: ¥1,900,000、Indirect Cost: ¥570,000)
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| Keywords | 性決定 / 性的二型神経回路 / doublesex / fruitless / 昆虫 / 進化 / 神経科学 / 発生・分化 |
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| Outline of Final Research Achievements |
Sexually dimorphism in the brain of the fruit fly is regulated by two transcription factor genes, fruitless and doublesex. In the fly brain, these genes are expressed as sex-specific isoforms to shape sexually dimorphic circuits. To reveal the evolutionary origin of neural sex determination system in insects, identification and characterization of these two genes was conducted in basal direct-developing insects including the two-spotted cricket. The result indicated that the fruitless gene of basal direct-developing insects does not possess molecular mechanisms for generating sex-specific gene product. On the other hand, the cricket brain expresses sex-dependent gene products of doublesex. These results support the idea that the doublesex gene is a prototypic neural sex-determination gene in basal direct-developing insects, and advanced holometabolous insects acquired an additional sex-determination mechanism regulated by the fruitless gene.
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| Academic Significance and Societal Importance of the Research Achievements |
我々ヒトを含む多くの動物は、脳の形態や脳を構成する神経回路に雌雄差（性的二型）が存在する。本研究では昆虫を材料に、性的二型が作られる遺伝的メカニズムと脳の発達メカニズム、そしてその進化を理解するための研究を展開した。本研究の結果、モデル生物であるショウジョウバエ脳で主要な神経回路の雌雄差を決定する遺伝子であるfruitless遺伝子が、コオロギやゴキブリなどの原始的な不完全変態昆虫脳においては性決定に関与しないことなど、昆虫脳における性決定メカニズムの多様性を示す結果を得た。脳の性的二型は性行動の発現に重要だと考えられることから、本研究から昆虫における性行動の神経基盤の多様性が示唆された。
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