Comprehensive research on hemiclonal hybrids - Demonstration of persistence and genome deletion mechanism

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K05743
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 40030:Aquatic bioproduction science-related
• Research Institution: Hokkaido University
• Principal Investigator: Munehara Hiroyuki 北海道大学, 北方生物圏フィールド科学センター, 教授 (80212249)
• Co-Investigator(Kenkyū-buntansha): 藤本 貴史 北海道大学, 水産科学研究院, 准教授 (10400003)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 半クローン / 染色体不和合 / 交雑 / ゲノム削除 / ホストスイッチ / ヘテロクロマチン / アイナメ属

Outline of Final Research Achievements

By changing the host species, we demonstrated that the lifespan of the strain was extended through repetition of hemiclone and recombinant generations. Hemiclone was mated with a male white-spotted greenling, which is distributed even in the coldest regions, and the resulting offspring were incubated, and the offspring were allowed to mature to create a grandchild generation. The results showed that the half-clones were able to interbreed with white-spotted greenling, all of the offspring were female, and the eggs they produced contained only the hemiclone hybrid genome. Furthermore, we investigated the process by which the paternal genome is deleted during oogenesis. At the early stage of development, the paternal genome becomes heterochromatine (inactivated) in hemiclones, and its expression is suppressed and inactivated before meiosis.

Free Research Field

魚類生態学、遺伝生態学

Academic Significance and Societal Importance of the Research Achievements

半クローンやクローンは雌だけを産むため個体群増殖速度が速いが、遺伝的な多様性を作り出せない欠点から系統寿命は短いと考えられてきた。しかし、アイナメ属雑種は、一世代で父親ゲノムを「置換」できる半クローンの特性を使い、同種雄を含み交雑相手の種を変えることで、半クローンと組換え世代を繰り返す（ホストスイッチ仮説）ことを実証した。本研究の成果は、ホストスイッチ仮説がこれまで知られていなかった種でも可能であることを示し、アイナメ属が北太平洋でもっとも繁栄する属の一つである要因を実証したとともに、様々な種で見られる自然クローン集団の出現と、それが維持される仕組みの一端を解明した。