Comparative genomics of metabolic strategies and speciation in genus Hydra.

2021 Fiscal Year Final Research Report

• Project/Area Number: 18K06364
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 45020:Evolutionary biology-related
• Research Institution: Okayama University
• Principal Investigator: Hamada Mayuko 岡山大学, 自然科学学域, 准教授 (40378584)
• Project Period (FY): 2018-04-01 – 2022-03-31
• Keywords: 共生 / 進化 / ゲノム / 刺胞動物 / ヒドラ / クロレラ

Outline of Final Research Achievements

To elucidate the mechanisms of adaptation and speciation in animal evolution, we performed comparative genome analyses among cnidarians and between closely related species using hydras, which have different nutritional acquisition strategies depending on the species. The genus Hydra includes green hydras, which established mutualistic relationship with the symbiotic Chlorella, and brown hydras, which are predatory and have relatively large body. Their genomes are thought to reflect different survival strategies. In this study, we show differences in the distribution of RNA transposons in the genome of green hydra compared to that of brown hydra, an increase in the number of genes and domain complexity of innate immunity genes, and a gradual loss of genes related to body plan such as homeobox genes, and clarify the phylogenetic evolution and speciation from a genomic perspective.

Free Research Field

進化生物学・ゲノム科学

Academic Significance and Societal Importance of the Research Achievements

ヒドラは飼育が簡単で、シンプルな体制や高い再生能力を持つことから発生・再生生物学の実験動物として使われているが、中でもグリーンヒドラは藻類を共生させ代謝産物を交換するユニークな性質を持つ。本研究で明らかにしたグリーンヒドラゲノムは、発生・再生生物学だけでなく、進化生物学や生体制御学などの有用な情報基盤となる。また、その動物―藻類共生系における知見はサンゴの白化現象のような環境問題への対策や、ミクロ閉鎖生態系における効率的な物質循環システムの絶好のモデルともなり得る。