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蛇的无肢和轴向模式的发育基础
1Division of Zoology, School of Animal and Microbial Sciences, University of Reading, UK. M.J.Cohn@reading.ac.uk
Nature
|June 12, 1999
概括
蛇的进化涉及显著的体型变化,但它们的发育起源尚不清楚. Python 胚胎中的 Hox 基因扩张解释了肢体丧失和干部延长,揭示了关键的进化机制.
科学领域:
- 发育生物学是发展生物学.
- 进化生物学是进化的生物学.
- 比较解剖学的比较解剖学.
背景情况:
- 蛇的进化特点是脊椎动物主要的体型变化,包括肢体丧失和干部延长.
- 这些蛇的进化变化的发展基础在很大程度上是未知的.
- 肢体损失和干部延长的结合表明,跨种群的共同发育机制.
研究的目的:
- 为了研究胚胎中蛇特异性体型变化的发育基础.
- 确定霍克斯基因表达在前肢缺失和后肢减少的情况下所起的作用.
- 探索涉及到四肢发育和潜在的救援机制的信号通路.
主要方法:
- 在前后轴沿的python胚胎中分析Hox基因表达模式.
- 研究后肢芽的启动和关键肢体信号通路的激活 (峰脊,极化区域).
- 使用纤维细胞生长因子 (FGF) 和小顶脊再组合的实验操纵,以评估救援的四肢发育.
主要成果:
- 沿着python体轴观察到扩展的Hox基因表达域.
- 这种霍克斯基因扩张与前肢的缺失和增加的胸椎脊椎身份相关.
- 猎的后肢芽开始发育,但由于缺乏顶峰脊和极化区域信号而无法发育.
- 肢体芽的生长和Sonic刺在pythons中的信号可以通过FGF或小的顶峰脊来挽救.
结论:
- 在python胚胎发生过程中改变的Hox基因表达是前肢损失和轴骨延长的主要驱动因素.
- 在中,四肢发育的失败与关键四肢信号通路的失调有关.
- 这些发育变化,可能源于霍克斯基因调节的早期转变,为蛇体图的进化提供了洞察力.
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