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低変異率だが,短命のオポッサムの生殖系に高い雄性バイアスがある
Yadira Peña-Garcia1, Richard J Wang1, Muthuswamy Raveendran2,3
1Department of Biology, Indiana University Bloomington, Bloomington, Indiana 47405, USA.
Genetics
|September 1, 2025
まとめ
灰色の短い尾のオポッサムは 低生殖線変異率を示し,男性の生殖線変異バイアスは 青春期後の細胞分裂にのみ由来するという考えに異議を唱えます この発見は哺乳類の変異率に 新たな洞察をもたらします
科学分野:
- 進化生物学
- 遺伝学
- 哺乳類の繁殖
背景:
- 両親の年齢と性別は哺乳類の変異率に影響しますが,その背後にあるメカニズムは不明です.
- 早期の繁殖を持つ種を研究することは,変異パターンに関する競合する仮説を区別するのに役立ちます.
研究 の 目的:
- 早期の生殖成熟度のあるモデル生物である灰色の短尾オポッサム (Monodelphis domestica) の生殖線変異率とスペクトルを調査する.
- 早期生殖が変異パターンと男性変異バイアスに及ぼす影響を調査する.
主な方法:
- オポッサムトリオの全ゲノム解析
- CpGサイト変異を含む生殖線変異率とスペクトルの分析
- 他の哺乳類との変異パターンの比較
主要な成果:
- オポスムは,世代ごとに最も低い哺乳類の生殖系変異率 (塩基対あたり0.252 × 10-8) を表しています.
- CpG変異は人間と比較して少なく,オポッサムゲノムのCpG含有量が低いと相関しています.
- 変異の3分の2は男性に受け継がれていましたが 後に繁殖する種よりも 男性のバイアスが顕著ではありませんでした
結論:
- オポッサムの低変異率は 早期の生殖年齢と一致しています
- オポッサムにおける観察された雄性変異バイアスは,思春期後の精子細胞分裂が唯一の要因ではないことを示唆している.
- 発見は,男性と女性の生殖系変異率の違いについて,思春期後の細胞分裂を超えた代替メカニズムを支持する.
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