Towards the elucidation of factors affecting the reproductive modes of the planarian Dugesia ryukyuensis.

2022 Fiscal Year Final Research Report

• Project/Area Number: 19K16175
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 44040:Morphology and anatomical structure-related
• Research Institution: Keio University (2021-2022); Hirosaki University (2019-2020)
• Principal Investigator: SEKII Kiyono 慶應義塾大学, 商学部(日吉), 助教 (50786358)
• Project Period (FY): 2019-04-01 – 2023-03-31
• Keywords: プラナリア / 生殖様式

Outline of Final Research Achievements

Some flatworms can reproduce both asexually and sexually, and switch their reproductive modes based on environmental changes, life cycle stages, or both. However, the mechanisms by which they switch between asexual and sexual reproductive modes are not well understood.
In the planarian Dugesia ryukyuensis, an experimental system has been established to convert asexually reproducing worms into sexual worms (sexualization), by feeding them sexually mature planarians. This feeding assay system enables us to study the factor that suppresses germ cell differentiation and keeps planarians in an asexual state. In the current study, I investigated the factors involved in the mechanism that maintains the asexual state, by using the feeding assay system, fluorescence in situ hybridization, and genomic analysis.

Free Research Field

動物学

Academic Significance and Societal Importance of the Research Achievements

ボルバキアのように、宿主のオスとメスの比を自分の都合良く操作する共生細菌の存在はすでに知られているが、無性・有性という宿主の生殖様式を変えられる共生細菌の存在はこれまでまだ報告がない。受精卵を経て次世代をのこす有性生殖にくらべ、分裂・再生によって数を増やすプラナリアの無性生殖は共生細菌の増殖にとっても有利となり、そのように自分の利益のために宿主の生殖様式を操作する共生細菌は興味深い報告となる。