Investigation of gamete recognition in the syncronous spawning coral Acropora

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K07414
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Developmental biology
• Research Institution: University of the Ryukyus
• Principal Investigator: Morita Masaya 琉球大学, 熱帯生物圏研究センター, 准教授 (80535302)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: ミドリイシ属サンゴ / 配偶子種認識 / 受精 / 生殖隔離 / 交雑

Outline of Final Research Achievements

The reef-building coral Acropora is species-rich and highly diversified in their morphology; species identification is often difficult because of its ambiguity. These features of the Acropora is supposed to be caused by hybridization and whole genome analyses support their hybridization. However, most of the species shows species-specific fertilization and their gamete species recognition is strict to accept the heterospecific gametes for fertilization. In this study, I investigated the relationship between reproductive isolation and gamete species recognition with the intercrossing species Acropora tenuis and Acropora donei. Those species could hybridize in vitro, but their gametes prefer to fertilize with conspecific gametes in the mix state of gametes from 2 species. Moreover, their population structure is distinctive and thus hyridization seems rarely occur within these species. Therefore, their gamete species recognition is enough for their reproductive isolation.

Free Research Field

生殖生物学

Academic Significance and Societal Importance of the Research Achievements

沖縄沿岸海域に分布するサンゴ礁の主たる構成者はミドリイシ属サンゴである。このサンゴ礁は様々な生物の棲家となるが、そのサンゴ礁はミドリイシ属サンゴの産卵時における受精が命の始まりになり、その後の維持に繋がる。したがって、本研究で明らかにしたミドリイシ属サンゴの同種で選択的に起こる受精選択のメカニズム（配偶子種認識）はサンゴ礁の維持に直結する重要な研究課題である。学術的にも、刺胞動物門に属するミドリイシ属サンゴの配偶子種認識を明らかにすることは、他の生物群にも同様に存在する配偶子種認識の祖先形質の理解にもつながり、さらには種を維持（生殖隔離）するメカニズムの理解に繋がることになる。