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カルシスポンジには,ParaHox遺伝子と分散したNKホメオボックス遺伝子のダイナミックな発現があります
Sofia A V Fortunato1, Marcin Adamski2, Olivia Mendivil Ramos3
11] Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgate 55, 5008 Bergen, Norway [2] Department of Biology, University of Bergen, Thormøhlensgate 55, 5008 Bergen, Norway.
Nature
|October 31, 2014
まとめ
動物の発達に不可欠なParaHox遺伝子は,スポンジが進化する前に存在し,以前の理論に挑戦しました. 石灰色のスポンジを分析すると,遺伝子進化の"幽霊の場所仮説"が確認される.
科学分野:
- 発達生物学 発達生物学について
- 進化の遺伝学 進化の遺伝学
- 動物学 動物学
背景:
- スポンジには,アンテナペディア (ANTP) クラスのホメオボックス遺伝子を含む多様な発達の転写因子があります.
- 双面的な動物は,ANTPクラス内のホックス,パラホックス,NK遺伝子を有する;デモスポンジゲノムにはホックス/パラホックスがないが,NK遺伝子のクラスタリングを示す.
- 以前の仮説では,ホックス/パラホックス遺伝子は,スポンジの分岐後にNK遺伝子から進化した,または,いくつかのスポンジで二次的に失われた,と示唆されていた.
研究 の 目的:
- 石灰色のスポンジにおけるANTPクラスのホメオボックス遺伝子の進化史を調査する.
- ホックスとパラホックス遺伝子の起源に関する"ゴーストロカス仮説"を検証する.
- 動物ゲノムと初期の動物進化の祖先の組成を理解する.
主な方法:
- 石灰色のスポンジ (Sycon ciliatum,Leucosolenia complicata) から得られたANTPクラスのホメオボックス遺伝子の系統遺伝分析.
- 比較ゲノミクスと合成分析.
- Sycon ciliatum.のANTPクラスの遺伝子の発達の表現プロファイリング.
主要な成果:
- 石灰色のスポンジは,二次的なNK遺伝子 (Hex, Hmx, Msx) と1つのParaHox遺伝子 (Cdx) のオートログを持っている.
- シコンでは,二国間の人々とは異なり,NK遺伝子クラスタリングの証拠は見つかりませんでした.
- Syconで分析されたすべてのANTPクラスの遺伝子は発達的に発現しており,細胞の特異化とパターニングの役割を示唆しています.
結論:
- パラホックス遺伝子はスポンジの起源より以前に存在し,二次損失の"幽霊場所仮説"を支持しています.
- 複数のスポンジ系統の研究は,祖先の動物のゲノムを再構築するために不可欠です.
- ANTPクラスの遺伝子は,動物の早期発育とボディプラン形成において,根本的な役割を果たします.
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