蛇の歯の進化的起源と進化について
Freek J Vonk1, Jeroen F Admiraal, Kate Jackson
1Institute of Biology, Leiden University, Kaiserstraat 63, PO Box 9516, 2300 RA, Leiden, The Netherlands.
Nature
|August 1, 2008
まとめ
蛇の歯は,前と後ろのいずれにせよ,おそらく共通の進化的起源を共有しています. 発達的なシフトにより,後歯は独立して進化し,ヘビの多様性に寄与しました.
科学分野:
- 進化的発達生物学 進化的発達生物学
- 比較解剖学の比較解剖学について
- ヘルペトロジー ヘルペトロジー
背景:
- 先進的なヘビには,捕食と防御に不可欠な,毒腺と結びついた特殊な歯,歯が備わっています.
- 爪は前頭部 (コブラ,ヘビなど) や後頭部 (草蛇など) で上に配置されている.
- 蛇の進化における重要な議論は,前歯と後歯の共通の進化的および発達的起源に関するものです.
研究 の 目的:
- 蛇の前歯と後歯の進化と発達の起源を調査する.
- 前歯と後歯が同型構造であるかどうかを判断する.
- 発達に関する洞察に基づくヘビの牙の進化のための新しいモデルを提案する.
主な方法:
- 8種のヘビの96個の胚の上の歯形成性表皮を調べました.
- 発達マーカーとして音響ヘッジホッグ遺伝子を利用した.
- 3Dイメージング技術を用いて41個の胚の牙の発達を再構築した.
主要な成果:
- 前歯は上下の後部から発生し,後歯と発達的に類似しており,ホモロジーを示唆しています.
- 前歯のヘビでは,発達過程により,歯が後部から前部の成人位置に移動する.
- 後歯は,独立した後部歯膜から発達し,後部位置を保持します.
結論:
- 前歯と後歯はおそらく同型であり,共通の後部発達源から発生している.
- 歯が形成される後部領域の発達的な分離は,クジラの独立した進化と改変を容易にした.
- この発達上の革新が,進化したヘビの有意な放射線と多様性を引き起こしたのかもしれません.
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