ウイルスとの共進化は,細菌の変異率の進化を促す
Csaba Pal1, María D Maciá, Antonio Oliver
1Department of Zoology, University of Oxford, Oxford OX1 3PS, UK. angus.buckling@zoo.ox.ac.uk
Nature
|December 7, 2007
まとめ
バクテリオファージ,またはファージは,バクテリアを進化させ,より高い突然変異率を発達させることができる. このバクテリアの適応は,ファグとの共進化によって引き起こされ,彼らの進化的軍拡競争に優位性を与える可能性があります.
科学分野:
- 進化生物学の進化生物学について
- 微生物の遺伝学
- バクテリオファージとバクテリアの相互作用
背景:
- 高変異率 (変異体) を有する細菌は,様々な環境や感染症で一般的です.
- 高い突然変異率は適応能力を高めますが,有害な突然変異を蓄積するリスクがあります.
- 寄生虫の共同進化のような,急速に変化する選択圧力は,高い変異率を維持する可能性があります.
研究 の 目的:
- ウイルス寄生虫 (ファージ) との共進化が細菌の変異率の進化を促すかどうかを調査する.
- 研究室の集団におけるバクテリア変異率に対するファグ-バクテリア共進化の影響を決定する.
主な方法:
- Pseudomonas fluorescensの集団を用いた実験室の進化実験.
- 制御された条件下でバクテリオファージ (ファージ) と共進化する.
- 変異率の測定と不一致修復遺伝子の変異の識別.
主要な成果:
- 菌素共進化集団の25%は,200世代以内に変異率が10倍から100倍増加した.
- ファグなしで進化する集団では,有意な突然変異率の変化は観察されなかった.
- 変異したバクテリアの集団は,ファグの集団を絶滅に追い込む可能性が高いことを示した.
結論:
- バクテリオファージとの共進化は,バクテリアの変異率を大幅に増加させることができます.
- 変異細菌は,共進化の軍拡競争でファグに対して優位性を発揮する.
- バクテリオファージは,細菌の突然変異率の進化を形作る上で重要な役割を果たしている可能性が高い.
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