Elucidation of molecular basis of sperm evolution in marine sculpin with different fertilization mode in the same genus.

2022 Fiscal Year Final Research Report

• Project/Area Number: 21K20676
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Multi-year Fund
• Review Section: 0703:Biology at organismal to population levels and anthropology, and related fields
• Research Institution: Osaka Metropolitan University (2022); Osaka City University (2021)
• Principal Investigator: Takeshi Ito 大阪公立大学, 大学院理学研究科, 特任助教 (10908429)
• Project Period (FY): 2021-08-30 – 2023-03-31
• Keywords: 精子 / 受精様式 / 精子競争 / RNA seqence / カジカ科魚類 / 体内受精 / 体外受精

Outline of Final Research Achievements

This study revealed that sperm heads elongate during the evolution of internal fertilization in marine sculpin of both North American and Japanese species groups, which differ in phylogeny. To clarify the adaptive role of the elongated head, we analyzed sperm motility in solutions with different viscosities and found no evidence of head elongation in response to viscosity. On the other hand, in closely related species, sperm motility differed greatly between external fertilization and internal fertilization, with amplitude motility in externally fertilizing species and rotational motility in internally fertilizing species. In addition, the RNA sequences of sperm of Artedius, a genus which contain both externally and internally fertilizing species, allowed us to select candidate genes whose expression levels differed depending on the type of fertilization mode

Free Research Field

進化生態学

Academic Significance and Societal Importance of the Research Achievements

これまで、精子の構成成分や受精そのものに関する研究は多くなされてきた。しかしながら、受精に至るまでの過程での精子の適応進化については見過ごされてきた。本研究は、進化生態学の観点から精子の適応進化を明らかにしただけでなく、精子形態の違いを機能面からも検証した研究である。そのため、複合的な視点から精子の適応機構を捉えることができた点で、学術的意義がある。加えて、RNA seqenceにより体外受精から体内受精種へ進化する際に発現量が変化した遺伝子の候補を選出することができた。これらの遺伝子を調べ体内受精に必要な要素を明らかにすることで、将来的に薬学への応用が期待できる。