胎児の進化におけるクローアカル位置の相対的なシフトは,外部生殖器の位置を変化させる
Patrick Tschopp1, Emma Sherratt2, Thomas J Sanger2
1Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA.
Nature
|November 11, 2014
まとめ
脊椎動物における外部生殖器の進化は,発達起源のシフトを示しています. いくつかの種では,四肢と生殖器は,共通の発達の出発点を共有しており,祖先の四肢のような起源を示唆しています.
科学分野:
- 発達生物学 発達生物学とは
- 進化生物学の進化生物学について
- 比較解剖学 比較解剖学とは
背景:
- 脊椎動物の地球化により,移動と繁殖の適応が必要になった.
- から四肢への移行はよく研究されているが,外部の生殖器の起源は不明である.
- 遺伝子発現の類似性は,四肢と生殖器の間の進化的リンクを暗示しているが,発達のメカニズムは不明である.
研究 の 目的:
- 外部生殖器の発達と進化の起源を調査する.
- 肢と生殖器が共通の発達経路を共有しているかどうかを判断する.
- 生殖器発達の多様化を促すメカニズムを解明する.
主な方法:
- 高解像度イメージングのためのマイクロコンピュータトモグラフィー (マイクロCT)
- 3つの胎児群 (ハゲワシ,ヘビ,マウス) での系統追跡.
- 転写プロファイリングのためのRNA-シーケンシング (RNA-seq).
主要な成果:
- 外部生殖器の発達は進化しており,一部の分類では,四肢と生殖器の間の共通の原始を示しています.
- 状動物では,後肢の芽から生殖器が発達し,マウスの場合は,腹部と尾の芽メセンキムから生じる.
- クロアカ (生殖器組織センター) の位置は,生殖器の成長のための細胞の採用に影響し,シグナル応答は保存されます.
結論:
- 外部生殖器の発達に対する祖先の条件は,おそらく,四肢のようなものである.
- 進化の過程でクロアカの位置が変化すると,哺乳類の生殖器の発達が変化した.
- 哺乳類の生殖器の発達は,共通の進化的起源のため,先祖の肢体分子回路を保持しています.
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