New Stage of Development for Fish Breeding Business: Simple Mass Production Technology of Doubled Haploids

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K06242
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 40040:Aquatic life science-related
• Research Institution: Kindai University
• Principal Investigator: Kobayashi Toru 近畿大学, 農学部, 教授 (00298944)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 倍加半数体 / 染色体操作 / 雌性発生 / 卵割阻止 / 中心体 / 中心小体 / ホモ接合

Outline of Final Research Achievements

The objective of this research is to put clonal line breeding into practical use in fish aquaculture. In other words, this project aims to study the effect of "multiple heat shock treatments" on suppression of cleavage of gynogenetically developing eggs and to realize the mass production of doubled haploids (fully homozygous monogenetic diploids) as breeding material. In this study, we used honmoroko (willow gudgeon Gnathopogon caerulescens) as the main material. The appropriate conditions for the production of doubled haploids of this species are as follows. 1. UV irradiation of about 20 mJ / cm2 is effective for genetic inactivation of sperm. 2. The appropriate one-minute treatment temperature for suppression of egg cleavage is 40.5°C. 3. The first and second heat shock treatments were timed at 25 and 40 minutes after fertilization, respectively, at 20°C culture. 4. Two or three repetitions of heat shock for 1 minute are effective for Gynogenetic egg doubling.

Free Research Field

染色体操作を用いた育種技術開発

Academic Significance and Societal Importance of the Research Achievements

本課題で検討している「熱ショック反復処理を利用した卵割阻止によるゲノム倍加効率の向上」は、純系育種素材の作出頻度を向上し、遅滞している水産分野での純系育種事業に選抜操作や系統間交配を加えた展開をもたらすと期待される。また、凍結保存精子の遺伝子のみで発生させた雄性発生体を生存性のある二倍体にすることにも応用できることから、希少魚種の保存や復元にも貢献できると期待される。すなわち、高温刺激の反復処理によって卵割阻止効率が向上すれば、絶滅に瀕している魚種を、その凍結保存精子と他の近縁種の卵を使用して希少種を雄性発生二倍体として復活させることにも応用できる。