类动物进化中的数字损失以及选择和约束之间的相互作用
Merijn A G de Bakker1, Donald A Fowler, Kelly den Oude
1Department of Integrative Zoology, Institute of Biology, Leiden University, Sylvius Laboratory, Sylviusweg 72, 2333BE Leiden, the Netherlands.
Nature
|July 9, 2013
概括
鱼和鸟类的进化数字损失揭示了成年数字消失后长期存在的发育遗迹. 后肢数字V中保存的基因网络与翼数字I的快速丧失形成鲜明对比,突出了与选择压力的发展约束.
科学领域:
- 进化发育生物学 进化发育生物学
- 进行比较的基因组学.
- 四足动物四足四肢的进化
背景情况:
- 进化的数字损失受到自然选择和发育约束的影响.
- 现存的类动物 (鱼,鸟类) 由于选择性压力而表现出不同的数字数量.
- 丢失的数字可以作为胚胎遗迹持续数百万年.
研究的目的:
- 调查尼罗河鱼和五种鸟类中数字损失的发育基础.
- 了解基因表达和发育约束在肢体进化中的作用.
- 探索数字丢失期间胚胎和成年人表型之间的不匹配.
主要方法:
- 在选定的物种中,对三个连续阶段的数字发育标记进行了检查.
- 分析了基因表达模式,包括声波刺 (Shh),Hoxd11,Hoxd12,Gli3和Alx4.
- 在翅膀数字I和后肢数字V中比较了数字持久性和基因表达.
主要成果:
- 翅膀数字I及其发育标记在两个独立的血统中丢失.
- 在所有采样物种中,后肢数字V作为软骨和Sox9-表达性前软骨域存在.
- 保存后部基因网络 (Hoxd11,Hoxd12) 即使在数字数量减少的物种中也被观察到,而前部基因 (Gli3,Alx4) 显示出变异.
结论:
- 后肢数字V持久性可能是由于保留后部基因网络和发育约束 (极化活动区域相关网络).
- 翼数字I的快速损失可能源于ZPA独立规范和较弱的发展约束.
- 一个整合发育约束和选择压力的模型解释了各种四足动物的数字损失模式,并告知了成人选择如何影响发育.
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